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Do you wear an Oura Ring, Whoop Band, FitBit, Apple Watch, or other fitness tracker, or ever thought about getting one?

Advances in technology and people’s desire to take their health and fitness into their own hands have made wearable fitness devices more popular than ever.

These tools claim to offer us unprecedented levels of insight into our health and well-being, but how accurate are these devices when it comes to tracking your heart rate, step count, total daily energy expenditure, sleep, stress, or recovery? Are these gadgets really that useful?

Paul Hough returns to the podcast to discuss the topic of wearable fitness technology and the “quantified self” movement.

In case you’re not familiar with Paul, he’s a Senior Lecturer in Sport and Exercise Science at Oxford Brookes University in the UK and has published several studies in academic journals. He’s also a fellow author, and his new textbook, Advanced Personal Training, which aims to turn science into applicable practice for personal trainers. And on the hands-on side, he’s worked with elite-level athletes in tennis and Formula One.

In this interview, Paul and I discuss . . .

  • The “quantified self” and what wearable tech can tell you about your health
  • The accuracy of these gadgets and how useful they really are 
  • What these devices are good at (and what they’re not good at)
  • How tracking can be counterproductive and the importance of considering why you’re monitoring
  • Heart Rate Variability (HRV): who should track it and why
  • And more . . .

So, if you’re interested in wearable fitness devices and want to learn whether you should buy one, listen to this podcast and let me know what you think! 


0:00 – Please leave a review of the show wherever you listen to podcasts and make sure to subscribe!

3:53 – Is it important to track our health with health & fitness trackers?

12:27 – What are your thoughts on health & fitness trackers?

43:30 – Legion VIP One-on-One Coaching:

46:18 – How well do health & fitness trackers measure recovery and stress?

52:54 – Who should we track HRV and why?

1:03:30 – Is there anything you would like to add?

1:06:04 – Where can we find you and your work?

Mentioned on the show: 

Legion VIP One-on-One Coaching:

Paul Hough’s website:

Paul’s textbook Advanced Personal Training:

Paul’s Instagram:

Paul’s Twitter:

What did you think of this episode? Have anything else to share? Let me know in the comments below!


Mike: Hello and welcome to Muscle for Life. I am Mike Matthews. Thank you for joining me today to learn about fitness, tech, fitness, wearables. What’s useful, what is not useful. And I wanted to record this episode because there are more of these devices out there than ever before. And a few of them, like Aura and Whoop and Fitbit, uh, apple Watch and others have big marketing budgets.

And so more and more people are hearing about these things and asking me about some of the claims that some of these companies make. In some cases, they would have you believe that their little device is going to give you, uh, unprecedented insights into your health, into your wellbeing, into your ability to recover from your training.

And deal with stress into the quality of your sleep, and so on and so on. And in this episode, you are going to learn the truth about those types of claims. You’re going to learn how useful these gadgets really are, and you are going to be hearing from Paul Huff, who has been on the show before. He is a senior lecturer in sport and exercise science at Oxford Brooks University in the uk.

Paul has published several studies in academic journals. He’s also a fellow author. He recently released a textbook called Advanced Personal Training, which contains a lot of practical evidence-based information for improving body composition, improving performance, improving health. The title makes it sound like something that is only for personal trainers.

But if you like the type of material that I produce, if you like this podcast, if you like my articles, if you like my books, you probably will also like Paul’s book, advanced Personal Training because it contains a lot of practical evidence-based information for people who want to improve their performance, health body composition.

And it is equally, the information in the book is equally applicable to individuals who just want to do that with themselves as it is to people who want to do that in others personal trainers. Hey Paul, thanks for taking time to, to come back on the podcast and talk with me this time about quantified self fitness, uh, health and fitness gadgets, wearables.

Paul: Hi Mike. Yeah, thanks for having me on again. Um, looking forward to, uh, the discussion. . 

Mike: Yeah. Yeah. So this is, um, this is a topic I’ve touched on here and there. I’ve talked about activity trackers and how they’re not great for estimating calorie expenditure. Cause people will ask about that. Can they just go off of their Apple watch or their, like Fitbit or something for estimating their total daily energy expenditure?

No, I wouldn’t recommend that. I, I think I’ve commented on tracking H R V, but I haven’t had an in-depth discussion about these devices and the different metrics. The, the people who sell them promote and how important and useful is this stuff really. And so that’s why I wanted to bring you back on the show to get into all the details.

Paul: Oh yeah. It’s something almost, uh, fairly regularly about as well because more and more people are kind of using fitness trackers and apps and things and uh, they’ve certainly become more popular. And the 

Mike: marketing is good on some of these devices. They do a good job selling them and making you think that maybe, maybe these devices are not entirely necessary, but maybe you could put them in the category of like, supplements not necessary, but certain supplements are going to materially improve your regimen, which then can improve your results.

And of course, the question that many people have is, how true is that with these devices? Like, does it really matter if we track our H R V or what about our recovery scores or stress levels or tracking our sleep quality and then trying to calibrate our training or, or physical stress levels to how we sleep and on and on and on.


Paul: it’s become a lot more popular since devices have become more accessible and affordable and the technology’s improved as well. So there’s this kind of movement known as the the quantified self whereby. People are taking more ownership of their own health and fitness by measuring various metrics on themselves.

So of course, the years ago you weren’t really able to do this. I mean, the best we had was like speedometers, which, you know, suffered bad accuracy problems. And then of course, since fitness trackers and smart lodges have, um, evolved, they measure more and more things. So people have become more interested in sort of cracking and it’s just become a lot easier beforehand if you, if you wanted to measure your physical activity, even if you had an objective measure, like a step counter, you know, it’s still just log it manually and you’d have to kind of note that down in your own diary and keep a record, which, you know, adherence to that was pretty poor.

So it’s kind of mainly used more so in research, but. These devices, they pretty much all sync up to an app, which automatically downloads your data, gives you your scores and information, which is, you don’t really have to think about it much, which is, so there’s a very low barrier to entry now on these things.

But as you touched upon, one of the things that’s um, important is accuracy and certain devices, I think there’s certain metrics like step counts now, which most devices, particularly of the established brands like Apple, Fitbit, and, uh, garment et cetera, being validated for step counts. So they provide a really good measure of your daily steps, like you mentioned.

When it comes to energy expenditure, this is, um, a lot more difficult, probably impossible to measure accurately, uh, using a risk one device. So it used to be that the devices would just use step count accelerometer in your device to work out movement, and then the play algorithms to that data to give you energy expenditure.

But, One of the big problems with it is that when we move, we move in different ways. So for example, running is different to to growing, uh, which is different from walking. So the algorithms have got more sophisticated. So they’ll work out kind of what you’re doing or you could tell your device what you’re doing, but ultimately then they’re measuring energy expenditure or estimating it through your movement.

When of course, most accurate way to measure energy expenditure is through using indirect color imagery or direct color imagery, which actually involves measuring your metabolism. So how much oxygen you’re using, basically, which of course, these devices can’t do a 

Mike: mask and going on a treadmill or whatever.


Paul: So anything above what we would call a, like a steady state. So that’s an exercise intensity that you would ma maintain for a long period of time. So for example, if you go out for a 45 minute run and you tell your tracker, your smartwatch, that that’s what you are doing. It’ll use an equation that’s appropriate for that and give you a reasonable estimate provided the data you’ve put into your device is accurate in terms of your age, body mass decks as well.

But as soon as you start doing activities which are non-sustainable, like high intensity interval training, weight training, that type of thing, it’s really a best guess estimate and it’s not very accurate measuring those things just because what we call like a non oxidative contribution energy. In other words, it’s anaerobic and.

Even using indirect color imagery, we can’t measure that accurately. So if we can’t measure it accurately using lab grade methods, then these devices Yeah, they, they just can’t do that. They don’t have the capacity to do that. 

Mike: Yeah. And, and the added work of even, okay, let’s pull up the app. I’m about to start a weightlifting workout.

Okay. I just finished my workout in, in the case of trying to just estimate energy expenditures, it’s just not worth it. When there are some simple mathematical methods, this is what I tell people, that that will get you close enough as well. And then ultimately you are going to have to adjust based on how your body responds or not, or what is spit out of the, the mathematical method just works fine.

Okay? You wanna, you wanna lose some fat and you want to be somewhere between, let’s say 300 and 500 calories below your total energy expenditure each day. and you use a, a calculator, like I have a couple calculators over at Lesions website that we built just based on validated mathematical methods. You punch in your numbers, it says eat 2200 calories per day or whatever.

And of course that’s a range. So you try to, you you’re, you’re between twenty one hundred and twenty one three or 2300 per day, and you just do that and it works and you go, all right, cool. I guess I don’t need anything else. And so that’s where I always recommend people start. Don’t, don’t go to the tech and.

More onerous than it needs to be. Yeah, for 

Paul: sure. And one thing I’ll always come back to with, with clients and also with, when we look at this type of, um, equipment and technology with students is that you’ve gotta remember whenever we’re using a device, there’s a, um, amount of error associated with it, sometimes known as noise.

And that means that it’s usually your true value lies somewhere between sort of a higher limit and lower limit of, of error associated with the noise. So to give you an example on unlike a, a sleep tracker or which might be in a smartwatch or it might be a bespokes device, there’ll be a degree of error with that for sleep duration.

So it might be that your device has an half an a 30 minute error, so that means what your sleep duration report. It could be 30 minutes more than that, it could be 30 minutes less. So in order to detect if you had a true change in your sleep duration, it has to be above or greater than the error of the device.

So in other words, if you measure your sleep one week and it’s, uh, your average is seven and a half hours, and then next week it’s seven hours, you don’t know for sure that that’s a real change because it’s within the era of a device. So most devices will publish what the error of the measurement is, or better than it will.

They should be quite transparent with that, and that allows you to make more informed decisions. And it’s known in sports sciences, kind of the smallest worth world change. So we want technology, particularly in sports or testing athletes and looking at, for very small changes, we want devices which have a, a good signal, strong signal, and a relatively low noise so that we can detect the change and any device which has got a large amount of noise.

So in other words, If you were to say, measure yourself, let’s, um, use, uh, body composition scales as an example. If we were to measure yourself throughout the day, in theory, where your body composition could be changing, if your device has given you a large difference between measurements, then that’s a, what we call a noisy measurement, and that means that long term, you’re not gonna be able to detect a flu change.

So the, the equipment’s effectively useless. So whenever you are, you can kind of pilot, um, or test the equipment that you use and things like that. And if you are doing repeated measurements and you shouldn’t expect to change it, it’s giving you a change, then that device has got a large amount of noise and it’s probably not gonna be very useful.


Mike: that makes sense. And for people wondering about measuring body composition in particular, we don’t have to go into that in this interview because I wanna talk about some of these other things like, like sleep in particular and H R V and stress recovery. But I did do an interview a couple of months ago, probably three months ago, four months ago, with Dr.

Grant Tinsley all about measuring. Body composition and talking about different types of devices, scales, handheld devices and so forth. So anybody listening, if you are curious about that in particular, Paul and I are not gonna get into that here, but if you go and find the episode I did with Grant Tinsley, T I N S L E Y, it is specifically about that just to let people know in case they’re like, oh yeah, body comp, when, when are you gonna talk about body comp?

But let’s talk about, so I get asked, I dunno about you, but I get asked a lot about sleep tracking, recovery, stress, H R V, all those things kind of go together. I get asked about the aura ring in particular, the whoop band. There are a few of these, and that’s a big part of their. Value proposition, so to speak, of, you know, why, why they’re saying, this is why you should buy our device.

What are, what are your thoughts on those types of measurements and, and even those devices in particular, if you have anything to say about those devices. 

Paul: Yeah, this is something, an area I’ve been involved with recently because, um, I’ve been doing some research with colleagues, uh, where we have been looking into different tests and technologies, uh, that can be used to, to measure fatigue.

So we’ve been doing that in sort of a military context where it’s important to understand an individual’s level of fatigue so it can decide if they’re fit to be deployed in, in certain scenarios, particularly sort of like high risk scenarios. And there’s no real kind of one device or, uh, test that can do that.

You have to kinda use a battery of tests, but nevertheless, um, these types of devices, uh, are being explored. And going back to my previous point about sort of like using different technology, one of the. The tips I give people when they’re thinking of buying a device such as an aura ring or whip strap or whatever, and if they want to know it’s accurate, is to have a look quick search either on Bugal, scholar, PopMed, put that device in, and most of the time see if anybody’s researched.

Yeah, exactly. They’ll be what we call a sort of a validation study. It’s independent, so the manufacturers might have commissioned someone to do the study, or some researchers might have just selected those devices and basically they measure it against the the best or the gold standard. So for example, an ordering and whoop strap would be measured against psg, which is basically in the most accurate way of measuring sleep.

Usually you done in a lab because you’re connected to loads of sensors as like sensors on the e eeg, vicious brain waves, the um, EMG muscular activity and various metrics that are recorded to determine if you’re asleep or not. 


Mike: like it’s not very conducive to good sleep. , ironically, . 

Paul: Yeah, that’s one of, I actually, one of the problems with it is, uh, if you put someone in a sleep lab, it does, can affect their sleep.

So, um, that’s why there’s a lot of those devices been made sort of at home devices so that you can measure someone a, a few nights. But nevertheless, it’s, it is a lot of tech and there’s still a lot of analysis that needs to be done. So those, anyway, the whip strap and aura rings have, um, there is some validation studies against PSG to show that they’re, um, offer pretty good or reasonable accuracy in measur.

Sleep duration, onset of sleep, and, and also when you wake up as well, what the don’t or can’t do reliably and accurately at the moment is measures, sleep stages. So this is sometimes known as sleep architecture. So we, when we 

Mike: sleep, and that’s one of the things people seem to obsess about that I’ve seen is, is, oh, well how much deep sleep did I get versus r e m versus light?


Paul: actually, okay. I did a, um, so I. Q and a’s, uh, university, one of which you kindly participated in, um, a few months ago. And I had a, I was chatting with an expert on recovery, she halen and also, um, a woman sleep expert, Dr. Neil Stanley. And this question came up a couple of times because they both have researched sleep extensively, kneel in the military and with general population and China with athletes in particular, and questions that came up there were about sleep stages and people worrying that they’re not getting enough deep sleep based on what their devices fitting out.

But at the moment, those devices cannot accurately measure when you transition from sleep stages. There is some papers which show that they tend to be better at identifying r e m sleep, and that’s probably because they, that’s associated with changes in your heart rate variability. But in terms of transitioning from one stage to the other, you really have to take that information with a pinched, so it’s not not being consistently shown to be, uh, accurate against P S G.

Whereas the other metrics of like sleep duration, awakenings, they have been validated and they show reasonable accuracy from that. And the, 

Mike: do you remember approximately the margin for error? Just based on what you were saying? Cuz people might be wondering, cuz you had mentioned like, okay, it says that you went from seven and a half to seven, but that’s within the, the amount of error that is allowed.

So in reality it’s possible that nothing. 

Paul: Yeah, different studies have, um, reported different what we call sort of, um, levels of agreement between PSG and, and those devices. But in general, yeah, it’s tend in sort of our using real world terms, but it’s around that half an hour, the error on, on 

Mike: those devices.

No, that, uh, if you’re looking at bigger changes then, uh, hour, hour, large changes that that’s maybe more reliable than, than a 15 minute difference. Yeah. And the other thing 

Paul: that does affect it, and this is what isn’t always captured when you look at just group averages, is actually the. Quality of your sleep.

So if, if you’ve got someone that’s um, got fragmented sleep, meaning that they wake a lot, but then get back to sleep, then their date is gonna be less accurate than someone that’s got sort of sleep straight through. Um, because ultimately what the devices are doing is using movement as one of the, uh, sort of proxies for sleep alongside some other variables.

So you can get individuals that kind of asleep, but maybe move more within their sleep and it might be identified as an awakening. So even, even though it’s objective, there’s still kind of some individual variability in, in the amount of error you get from those devices. 

Mike: I’ve experienced that. So Whoop sent me, they’ve sent me two actually, which is, which is nice of them.

And I’ve used them mostly just for sleep tracking, just cause I was curious how the data would correlate with my subjective assessment of my sleep. And then, you know, just how I felt, uh, throughout the day. And if I’m gonna have a bad night’s sleep, it’s gonna be wakings, I’ll be able to fall back asleep.

But I’m gonna wake up several times. So usually I’ll fall asleep for a couple of hours and I’ll wake up. Sometimes I have to pee. and then I’ll fall asleep for another stretch of, maybe it’s two hours in the first and then I have to pee and then maybe four hours and I have to pee again. And then the final little bit of sleep.

That’s probably a normal night. On some nights it doesn’t happen all that often, but sometimes I’ll wake up every hour to two. And so to your point where at the end of a night like that, it says that I got a certain amount of sleep, but it does not feel , like I got eight hours or seven and a half or whatever.

And it takes more time in bed just to get there, of course. And with, um, the whoop. Band. They also, they, they give the disturbances. Now that was definitely correlated with actual wakings, even if it is just for five or 10 minutes and falling back asleep. And so on nights where I had under 10 disturbances, I felt pretty rested, felt pretty good nights.

Um, 10 to 15 were like, meh. Okay. And then 15 to 20 was a bad night. Like, I’m not, probably not feeling so good the next day. Yeah. And, 

Paul: and I’m the same. I’m, I’m, I’m a pretty bad sleeper. Um, it’s rare that I would ever sleep straight through. So not to mild get sort of like, uh, four hours e even with, you know, if both children don’t wake up.

But like you’ve just said that a lot of the time you. Know this intuitively. If you’ve had a bad night’s sleep and you don’t really, the device isn’t telling you anything that you dunno. 

Mike: And that’s why I stopped using it. I mean, we’ll get into the H R V and recovery itself, but it was kind of interesting, I guess just to see and the different, uh, stages, uh, of sleep.

I, I didn’t even look into the, to the accuracy or inaccuracy of those things. And so, Put much stalk in in that, but I was just more curious, total sleep and then disturbances and how that would correlate with how I feel. But to your point, I was like, well, um, I pretty much know within five minutes of waking up in the morning if I’m gonna have a good day or not.

So , that’s about it. 

Paul: Right? Yeah. There’s a lot to be said for intuition and that’s one of the things we’re sort of like this, the quantified self movement, is that you don’t really wanna outsource all of your sort of perceptions of your fatigue, sleepiness, and just general health and how you feel to a, to a device.

It’s important to, to keep in mind that yeah, that how you perceive sleep’s an important measure as well. Uh, there’s actually been some recent research on that that have shown that I think we was study in military cadets where the group that actually perceived they slept better and had a better immunity response were less likely to get ill than the the cadets that slept poorly.

So, There is some, some research out there. 

Mike: Even, even though objectively they were sleeping about the same, it 

Paul: was pretty similar. Yeah, exactly. So, so, so 

Mike: devices could even contribute to, and I’m sure this is kind of on your list of things you’re, you’re gonna wanna talk about. It could contribute to misperception or even anxieties about, let’s say sleep or some element of health that aren’t warranted, that are actually driven by the device leading somebody to believe that things are worse than they are.

Yeah, exactly. That’s, 

Paul: that’s a great point. Uh, 

Mike: like disturbances for example, I, I, I look online people, a lot of people are confused about that. Disturbances are not wakings, but, okay, 10 disturbances. That sounds pretty bad for, let’s say being in bed for eight hours. But I, I can say personally, I don’t know about you, but 10 disturbances, I’ll feel totally fine now.

15 to 20, I’m not gonna feel fine, but anywhere from five to 10. I’ll be like, yeah, yeah, it was not bad. I probably woke up in the middle of the night. But you know, I spend the time that I need to spend in bed and I get enough rests and I feel good, but I could also interpret 10 disturbances. It’s like if I’m only in bed, you know, between eight and nine hours, more than one disturbance per hour.

Wow. I’m a bad sleeper. 

Paul: Yeah, I mean that’s kind of one of the reasons I stopped. Um, I’ve used a diff of different devices cuz if we’re getting use something in reco, I’ll always try it on myself as well. I did one for about a year actually, and I think the most useful thing it gave me was, uh, pattern of.

What time I was going to bed and time I was waking up. Cause that’s, if you’re not a good sleeper, that’s one of the, the recommendations that’ll be made is to eat those better time and un wait time as consistent as possible throughout the week. So not trying to catch up here and there and, and, uh, not lying in et cetera.

So I I found that quite useful. Avoiding naps. Yeah, exactly. And that has been, I know, useful for a couple of clients I’ve worked with just as sort of a marker of, of when they’re going to bed and when they’re waiting. But yeah, like to your point, when you look at an actigraphy trace, which is kind of what, uh, you’ll see on most, uh, sleep reports where it kind of got a little graph and it will show a spike when you’ve woken up and, and weren’t asleep.

That can be quite alarming if you’ve got loads of awakening. I remember I compared my trace to my colleagues and his was just like a nice block. So sleep, wake, mine was just like an up and down graph or nine. Mine, not terrible, but I didn’t read too much. It’s hard. I can see why people would get concerned, you know, particularly if you kind of fixated on, uh, using the device to improve your sleep.

And to your point, that’s actually been shown in a, in a couple of studies that some devices or tracking can be counter product. So there was, uh, a study which, um, gave sham advice. So basically the device, the researchers set it to say you’ve had a really bad night’s sleep, and then in the other group they said you’ve had a good night’s sleep, or they, they manipulated the metrics, so it looked like one was really bad, one was really good.

Anyway, the, the group that was told they had really bad sleep reported feeling more fatigue, and the group that were told they had good sleep reported the opposite. So the objective data was falsified. It wasn’t true, but it, it changed their perception and also how they felt throughout the day as well.

So there’s not a lot of students that looked at it, but there’s definitely. Something in there which could potentially be counterproductive. And a few years ago, some research has actually coined the term or somnia, which is basically a preoccupation with this sort of desire to achieve really good or perfect sleep.

So similar to, you know, um, sorry, I 

Mike: missed the word. I haven’t heard this term. What is it again? Or insomnia? Like a U t H. Somnia. 

Paul: Oh, uh, t h. Okay. Okay. Yeah. So it’s, uh, similar to, you know, with people that track their 

Mike: nutrition. Yeah. Got it. Like orth. Yeah. It’s just the accent. That’s why I misheard 

Paul: it. . No worries.

Um, similar to that, which is why they, the researchers coined that term. Yeah. 

Mike: Like orthorexia, but orth. Yeah, exactly. 

Paul: Yeah. So preoccupation, we. Achieve perfect sleep, which is kind of a futile thing. Cause there’s no thing. Yeah. 

Mike: And I’ve heard from people where again, they, they’re, they’re maybe a little bit too simplistic about it and so they assume, for example, alright, fewer disturbances is better period.

So, and let’s say objectively, there’re actually sleeping quite well. There, there aren’t that many disturbances and they’re, but they’re concerned because it’s like five or six or seven and they’re trying to get it down to one. And so they’re taking every supplement that anyone anywhere recommends. And they have like a 45 minute bed routine that, you know, requires four different glasses and stretches and meditation and on 

Paul: and on and on.

I’ve spoken to a couple of different sleep experts and, and they say that, yeah, that compulsion around it actually can make your, it can create a problem that wasn’t there. So, for example, if you were. A fairly decent think of it, and then you’ve monitored it and then your device is telling you that you’re having not much deep sleep and then you start trying to kind of hack your sleep with these techniques and you create anxiety around it, then actually it’s counterproductive and and makes things worse.

So yeah, there is an element and certain personalities are more susceptible to. When you start monitoring something, you know, like maybe more type a’s that are kind of striving for the best. If you don’t consider that those devices have got that error and you are kind of taking what they spit out as as a hundred percent fact, then trying to improve those scores can become a bit futile because it might just be the error that’s being captured in your results and you’re trying to improve it when in actual part there’s nothing to improve, you’re, you’re sleeping perfectly well.

So yeah, there, there’s an element of caution with, um, over tracking and over surveillance of, of certain things and, and sleep’s. Um, it’s a passive process, so it’s not like, you know, if you want to get fitter, You have to do a training program relevant to your fitness goals. If you wanna sleep better, you can’t really hack that.

It’s, it’s something that happens to you. You can 

Mike: only like prepare the ground, right? You can only create the conditions in your life. And I think as one. Shaky sleeper to another like . You know what I’m saying? Right. I mean, you can, and there are physical conditions, emotional conditions, mental conditions, you could say spiritual conditions for people who even want to include that.

And all you can do is try to set yourself up with a lifestyle that’s conducive to good sleep. Least. That’s been my experience for sure. 

Paul: And, and also accepting that it’s gonna be variable and sometimes there’s no wrong or reason why you don’t sleep very well, but good sleepers don’t really dwell on those things and they just have a better sleep the next time.

And I, I 

Mike: don’t know about you, but you know, when I was, so 10 years ago, I was a great sleeper. I mean, I had a run of like five or six years. I remember talking about it on the podcast. I remember saying like, this probably won’t last forever, but I’m gonna enjoy it while I have it. Where, you know, I. Working every day after dinner, I do my dinner, do cardio.

So let’s say 7:00 PM I’m doing cardio with caffeine and yo, him being, if I were cutting right, didn’t, oh, whatever, who cares, stimulants, doesn’t matter. And then work for another couple of hours, maybe that’s 1130 now. Get off the computer, get ready for bed, quickly go to bed. No wind down time, nothing. Fall asleep within five minutes.

Blackout, unconscious for probably six and a half max, seven hours. Wake up for my alarm and just feel totally fine and do that every day for five or six years straight. And that was life then. And then one day I, I can remember the day vividly when I realized that. Wait a minute that this is like two nights of really bad sleep in row.

Like, what, what is this? What, what, what’s going on? And ever since then, , it has never been like that. And I don’t know if it ever will be again. 

Paul: Yeah. I think, um, yeah, I can vouch for that. I think, uh, there’s sometimes there’s no rhyme or reason. I think with me, I was studying for a master’s at the same time as, um, as working as well.

So sort of cramming, um, a lot of reading and stuff into the e evening and of course then your mind switched on and stuff. So, um, yeah, in, in those cases, going back to the tracking it, you kind of know that you’ve not slept well. You don’t really need a, a device to, to do that. So that’s why I don’t really track too much unless I’m trying out a new product for, that we might be using in a study or something.

Mike: Yeah. And, and I’ll also just say, and you can let me know if you disagree or have anything to add to it, but if somebody is sleeping well, if they, and, and we all know what that feels like, they’re probably also getting an appropriate amount of r e m and deep sleep that there’s probably not any major dysfunction.

If they are generally just sleeping well and they wake up feeling rested and they don’t particularly get tired throughout the day. There’s not that like afternoon where they’re just slump, where they’re like falling asleep. So there’s no reason, even if you could accurately track your different sleep stages, there’s not gonna be a problem there.

I mean, if there is a problem, you would know it. Yeah. And you 

Paul: can’t, you can’t shift yourself into different sleep stages anyway. So it’s, um, with, when it comes to fitness and health, te. If someone’s asked me about, I’ll say, well, what’s kind of the purpose of you measuring that? What, what outcomes do you want to achieve from it?

Um, it might just be out of curiosity and interest, which, which is fine. Um, but if, if people are using it to kind of try and improve, for example, sleep stakes, I would advise against that because one, it’s not measuring those. Within a accuracy to do that. And two, um, to my knowledge, there’s no way of actually kind of shifting yourself into a different stage of sleep.

It’s kind of a very passive process. And the research and a lot of sleep studies have shown us, if you, if you deprive people, they, they tend to go into deep sleep a lot quicker and skip through the, the stages. So the sort of the real restorative phase of sleep, when you look at sleep deprivation studies and the participants tend to go straight into that.

And, you know, I’ve experienced that using these devices where I’ve had four hours, but it’s been like knocked out for four hours and then I’m working up. Okay. And not saying that’s a healthy way to, to do it, but, you know, it’s just anecdotal. 

Mike: I know what you’re saying. Where you’re like, I feel strangely Okay.

For four hours 

Paul: of sleep. Precisely. Yeah. I’ve spoken to, you know, people with, um, like occupations like shift work and working in the military. Um, They’ve had, they had that very concentrated bowel of of sleep and, um, long-term effects, it’s, it’s not gonna do any favors. But in the short term, it, um, it seems to allow some people to preserve their sleep and Yeah, 

Mike: which makes sense.

Of course. I mean, the body is, is resilient and so it’s, it’s essentially, uh, figuring out a way to still stay functional despite non optimum circumstances. 

Paul: Yeah, exactly. It’s you, you, we’ve got these kind of short term ways of dealing with fatigue and lack of sleep. But by no means you wanna make that a long term habit.

But that’s why I think that’s where I see the utility in, in tracking is that, you know, if you think you’ve got problem and then you realize that you’re going to bed, you know, 10 o’clock one night, one o’clock the next morning, and then it’s all over the place, then you’ve identified an issue. So it’s been useful.

You can do that with a pen and paper diary, but it’s just more convenient to wear a cracker and most of them will give you that information quite accurately. Sort of like when you’ve gone to bed and when you’ve woke up. 

Mike: Yeah. Yeah, that makes sense. And one other thing I’ll share just for people, anyone who has sort of sleep issues, again, I particularly, I guess the, the term would be No, no.

There’s, there’s a, the type of insomnia where you just wake up a lot there. There’s a, there’s a, a technical term for it. Maybe you know what it is. I don’t remember. But, so that’s, that’s the problem I’ll run into if I have any problem, is again, the, the continued wakings. And then occasionally there was, there were even times where I would have trouble falling back asleep.

I’d get out of bed for 30 minutes and just read until I was sleepy and then go back to bed and fall asleep. But two things that have helped me, uh, in particular, uh, one is taking some time, and this sounds kind of stupid, but, um, this is something I just didn’t do for a long time. Making sure that I’m having some fun in my life somewhere, some.

And, and it sounds silly, but I, I think as you understand, as so, you know, with two kids and with a couple of businesses that I have to be involved in and a lot of stuff going on there, no, for a long time, I, I basically had no hobbies, no social life, and I would just work seven days a week. I would work full days, Saturdays, half days, Sundays when I got into this writing books and doing podcasts and creating educational material.

And that’s what I enjoy to do. And so then since then I’ve become an entrepreneur. And this is not a complaint, but it’s just a, I’ve learned that a lot of what goes into building a business is not very fun to me. Some of it is, but a a lot of it is not. And of course you gotta do things that are not quote unquote fun and that you don’t particularly enjoy to achieve certain levels of success and things.

But for me, I, I think I, I pushed. Myself for years and years and years to just do the next thing, whether I wanted to do it or not. And if I look at it in terms of like diagnosis, kind of pushed myself even maybe into what could be, what could qualify as mild depression. And I always thought of depression as, oh, I’m so sad I can’t get out of bed, and that’s not me.

So I just never even thought about it. But a couple of months ago, I, some came across something and some of those symptoms of mild depression, like irritability, not really enjoying things, not really looking forward to things. And some of the, some of the others, I was like, oh yeah, like that’s me. That’s, that’s a hundred percent.

But because it was something that I was actively creating, it wasn’t for no good reason, then I was able to, and, and I guess there’s even a technical. Term behavioral activation therapy, I think, which is basically like, okay, start doing things that you like to do, like make sure that you have some joy, some joyful experiences like scheduled in your life and do those things.

That immediately made a difference in my demeanor and this, this was. Maybe low grade. Oh. In, in any sort of insomnia, by the way, is is like one of the first things that if you were to see a professional that they would, that they would ask about. And apparently any type of depression often won’t even be diagnosed if there are no sleep troubles.

Um, at least that’s my understanding. Sure. They’re, 

Paul: they’re highly correlated with each other. 

Mike: Exactly. That’s like apparently one of the most highly correlated. And so simply realizing that and then taking some actions to even, even, okay, let me look at all the work that I’m doing. Some of these things I don’t have to do.

So maybe I take the, I don’t like doing ’em at all. Let’s take some of those things out and let’s just like put some things in. So I started coaching my son’s flag football team, right? Something I would not have done a couple of years ago because I was so work focused and just want to get to the next work thing.

Just little stupid things like that. Like, okay, let’s, let’s, let’s put some fun things in my calendar that I look forward to and let that counterbalance the, the maybe a little bit of the. Um, irritation that comes with doing a lot of other things that maybe I don’t really want to do, and my sleep immediately got better immediately.

Paul: That feeds into, I mean, I’m not, um, a behavioral psychologist, but, uh, there is quite a bit of research on, on sort of the field of, of play for adults and just that just means basically doing activities where there’s no kind of necessary producing something tangible or learning something. You’re actually just doing it for the sake of it, or for just for purely enjoyment.

And that kind of goes back to my point of our personality types and developing, uh, certain conditions like insomnia, preoccupation with sleep and uh, obsession over diet, that type of thing. You know, when you start getting into these habits, then it can actually be counterproductive for your health. And, uh, you know, I’ve, I’ve seen that with, there’s certain athletes, like some endurance athletes that, um, I’ve worked with.

They tend to. Be very interested in data and, and logging things and tracking things. And it can cause issues like if you quantify everything in your life and everything has a purpose and there’s gotta be a reason for it. And like you’ve just mentioned there that I’m not quite sure where to research sort of the, the, the mechanism for it is, but I think it’s probably since been kind of just having some downtime from.

Thinking about work or producing things 

Mike: or just, just trying to use every minute productively. And I was able to do that for a long time without necessarily, I guess you could say, having to pay the price. But I had commented on this in a recent q and a that. That allowed me to get a lot of work, but eventually it caught up with me and I would think that it would have the same effects in anybody.

So I was just telling people, I was like, this is what I did. I forget the question, but it was, I think it was kind of like a work-life balance question, like how do you have the time to work out and do the work and all this stuff? And then that was my answer was like, well I basically for a long time, just like did basically nothing that is really just fun for its own sake.

Like no hobbies, no, no social life, even like that, not not having regular interactions with people that you like outside of a work context that’s not good for your mental health. Like I would not recommend what I did for a long time. It. , I don’t think impact me maybe as much as some people would think that it would, given the circumstances and for whatever reason that is what it is.

But eventually, I mean, I think that’s really what I’ve been dealing with mostly over the last several years without realizing it. And I’m just a kind of a stubborn, goal-oriented person, so I can just keep going. But it, it was, again, I, I think I was causing the problem myself that, that then I was trying to find other ways to deal with as opposed to understanding that, uh, it appears with me.

A big part of it was again, like making sure that I’m not spending all of my time doing things that maybe make sense, like they can be rationalized and they contribute toward some goal that makes sense, but it’s not particularly enjoyable. It just need it, you just need to do it to get to the goal, you know?

Paul: Yeah. I mean, yeah, do things. I’ve recently spoke with someone that was really on the, uh, kind quantified set for two weeks, green levels. He was talking about how he goes to bed at, um, oh, sorry. He has dinner at like five o’clock every night and he’s in bed by 10 because, you know, that falls inside of his.

Optimal circadian rhythm and he’s kind of like living his, I mean, you know, each to their own. But, um, I feel that there’s gotta be some flexibility with your schedule if you’re kind of just trying to live to what’s optimal. Uh, it might not be the most fun way of living. 

Mike: Yeah. Yeah, exactly. And one other thing that seems to, to help and there’s some research to support it, is getting, getting sunlight early in the day.

It’s something that I just didn’t consistently do really. I guess I didn’t really ever make it a thing, but I have noticed that I’ve been doing it consistently now just to make sure to get out in the morning, wake up, go for, just go for a walk. I’m in Florida, so it’s sunny a lot. That also helps. But, um, consistently getting, let’s say anywhere between 20 and 30 minutes of sun in the morning time also seems to help.

And there’s some research to support that. Oh yeah. 

Paul: That’s, that’s one of the strongest drivers of our, um, regulators of our circadian rhythm is, is natural. But yeah, natural daylight is, is one of the, uh, the, the best setters of our, uh, circadian rhythm and, uh, biological clock. So, but even then, you know, people are trying to hack that with sort of, um, lumen lights and things, which, um, can help.

But most of ’em are anywhere near power. Powerful enough, or don’t give the same looks that are natural, natural daylight would. Yeah. 

Mike: Uh, my understanding is that probably better than nothing if you’re in a. Where there is no sunlight. But even then, and this is, this is basically my limited understanding, I’m just reading up, driven by sleep, right?

Just understanding things that even, even if there’s a cloud cover, you’re still gonna benefit from, from getting out there and exposing your, your eyes and, and your body to, to that natural light. Yeah. 

Paul: Even with cloud coverage, it’s that frequency of light is still significantly, uh, more powerful than, than a, a lamp would be.

I bet you’re right. You know, if you live in a, a country where it’s dark a lot time or, or 

Mike: you’re in Alaska and you’re in the darkness phase, . Yeah. 

Paul: I mean, I, I just anecdotally I train in a gym, which is in the basement. I really don’t like it. Uh, just go the, out of going in from daylight, intimate, dark area.

I know some people like that kind of dungeon start gym. I, I just like, uh, windows and, and daylight and, um, yeah, I think, yeah, there’s doing some, some, some research on that actually. Like people tend to do better in the daylight than if you put them into a dark kaist gym. Interesting. 

Mike: I’ve worked with tens of thousands of people over the years, and the biggest thing I see with the people I have helped the most is they’re often missing just one crucial piece of the puzzle.

And if you are having trouble reaching your fitness goals as quickly as you’d like, I’m gonna guess it is the same thing with you. You are probably doing a lot of things right, but dollars to donuts, there’s something you’re not doing right, and that is what is giving you most of the grief. Maybe it’s your calories, maybe it’s your macros.

Maybe it’s your exercise selection. Maybe it’s food choices. Maybe you are not progressively overloading your muscles and whatever it is. Here’s what’s important, once you identify that one. Once you figure it out, that’s when everything finally clicks. That’s when you start making serious progress. It’s kind of like typing in your password to log into your computer.

You can have all the letters, numbers, and symbols write except just one. And what happens, you can’t log in, right? But as soon as you get that last remaining character, right, voila. You’re in business. And I bet the same can be said about the body you really want, you are probably just one major shift, one important insight, one powerful new behavior away from Easy Street.

And that’s why I offer v i p one-on-one coaching where my team and I can help you do exactly that. This is high level coaching where we look at everything you’re doing and we help you figure out that one thing that is missing for you. And it can be a couple of things too, that’s fine. There’s no extra charge for that.

But once we figure it out, that’s when you start making real progress. That’s when you start looking better and feeling. So if you’re ready to make more progress in the next three months than maybe it did in the last three years, and yes, that has happened for many of our clients. Head on over to Muscle for Life Show slash vip.

That’s Muscle, F O r, life Show slash vip, and schedule your free consultation call, which by the way is not a high pressure sales call. It’s just a friendly chat where we get to learn about you and your goals and your lifestyle, and then determine whether our program is right for you. Because sometimes we do speak with people who just aren’t a good fit for our service, but we almost always have other experts and other resources to refer those people to.

So if you are still listening to me and you are even slightly interested, go schedule your free consultation. Call now at Muscle for Life Show slash vip. So, so anyways, let’s, let’s segue back to, um, the devices and, and can you talk to us about H R V Recovery, stress, these measurements, cuz that little cluster of topics and sleep, those are the two things at least that I get asked the most about.

Heart rate usually goes into it as well, obviously, but yeah, 

Paul: I mean, heart rate variability is, um, it’s been used useful quite a long time within sports science, but it’s been commercialized more recently in, in terms of, it’s available now in smartwatches and fitness trackers and it’s, uh, it’s a measurement of.

Variation in time between your heartbeat, so your heart doesn’t beat like a metronome or it shouldn’t, uh, there’s a small variability between those heartbeats. And by measuring that over a period of time, we can actually, uh, detect, or we use it as a proxy for measuring how the autonomic nervous system is functioning.

So the autonomic sys nervous system basically runs in a, it’s like our background operating system. So when you are stressed, for example, if you’ve got a deadline or you’re late for something, there’s a branch of the nervous system called the sympathetic nervous system, which kind of primes your body for activity that often known as the fight or flight response.

So you get enough regulation of, of hormones, Papo, like the adrenaline cortisol, which prime you to do something. So cortisol peaks in the morning, which is why, largely why we wake up. So what the, uh, heart rate variability to do is give us a measurement of balance between that sympathetic nervous system and the opposite branch of our nervous system, which is the parasympathetic nervous system.

And this branch of the nervous system opposes the sympathetic system, so it’s associated with rest and relaxation. So when we, for example, before we fall asleep, we’ve got an increase in parasympathetic tone, which is causing downregulation of our bodily processes and hopefully sending this to a restful sleepful stay.

So by measuring heart rate variability, it gives. An indication of the balance of that. So whether the body’s recovering or experiencing stress or it’s in a mortal, parasympathetic state of recovery. Now, what devices do is that they measure your heart rate variability, and then a lot of them will give you a score, like a some, sometimes it’s known as a readiness score or a fatigue score, where the, and this is where it gets tricky because each manufacturer will have a different algorithm to calculate that.

Some will call it a stress score and some will call it like charge. So they can’t be used interchangeably. You can’t use, um, a whoop strap and an AING score because they’ve calculated your stress differently. They’ve used heart rate variability, but the algorithms that applied are different. Uh, but in any case, they’ll give you a, a score, which gives us, gives you a global sort of idea of your level of stress.

Now when, when heart rate variability is being used in sort of sports science with athletes, most of the time we’ll just look at the actual da, the heart rate variability data, so it’s not plugged into a a readiness equation because one of the problems with those is they’ve not been validated. So going back to fitness tech and looking at validation studies, they measure heart rate variability.

Most devices with good accuracy. So Aura Room has been validated. I believe we strap has as well, but the recovery score has not been validated. So we don’t know for sure if that’s sensitive enough to be able to say you are recovered or not. So it’s a problem if you are using those and, 

Mike: and my experience with the whoop strap is, I mean, I, I quickly started to ignore the recovery score because I, I remember clearly nights where I slept totally fine.

I felt great, had had a good workout that day. My workouts were not like preceding that or just my normal training. Like I wasn’t training, I wasn’t in an overreaching period or anything. And, but according to the whoop strap and the whoop app that morning, it was like a, a red recovery, like a 20 out of 100.

And then I had experienced it the other way around, have a really bad night’s sleep, and of course not feeling good and you don’t have a great workout. You just kind of grind through it. According to the whoop strap, you know, it was like a nineties recovery and you should be ready to push hard. So I quickly started to ignore the recovery score, but I, I would pay attention to the H R V trend just out of curiosity.

Exactly. And that, 

Paul: that’s what I would advise people looking at that is look at the, the H R V itself, not the, the recovery or readiness score, similar to sleep stages on the watches. Um, and the bands maybe don’t read into those as much, but, and that’s the key thing with high A variability, is you have to have, use it for a long period to get a true indication of your baseline or what’s normal, because everyone’s H R V will be different, and the way your HIV responds to a stressor will be different.

So it’s important that you, you have period. What the device is doing is establishing your baseline, so then it can try and detect where there’s been, going back to my previous point, what’s the smallest worthwhile change? So trying to distinguish between what’s just general variability, day-to-day variability and actual, uh, significant change.

And confuses measurements, which is why they can’t be used interchangeably between devices is when they measure. So I believe, I think it’s the, the weak strap, which measures across the night and then averages other devices. Like there’s an, a validated app where you put it on your phone and you. Use the camera.

Uh, basically the flash from the camera can measure, um, and detect your heart rate variability. That has to be done in the morning at a consistent time. The morning approach is probably best because if you use a device which averages across the night, it is susceptible to what you’ve done in the evening.

So, for example, if you had a, a later evening, mild than usual or drank alcohol, that tends to be one of the things that affects HIV v the most. It will affect your HR V score, so it’ll give you an indication of what’s happened the night before. Whereas the a morning reading, if you do it consistently, uh, tends to give you a more reliable reading of your readiness for the day, if you like.

Yeah, yeah, that makes sense. 

Mike: And who should even bother track? H r b and why, and why? It 


Paul: from sports on athletes tracking it, and the, the reason why it’s done in sport, uh, particularly in elite sport is to understand how athletes are responding to training. Because professional athletes, although the training is, um, obviously, um, higher intensity and their load is greater than sort of your average person, their training is, is more predictable and it’s their full-time job.

So it’s training, it’s more likely to have an effect on H R V. Um, so, so if you go for a heavy training block, your H R V, um, score should decreases. It should a higher level of stress. So it’s been used historically in sport to identify when athletes maybe are not recovering well or maybe need more recovery going into a competition.

For example, if you’re using it outside of, uh, sport, it can give you an indication of sort of maybe certain activities which affect your stress levels. So I mentioned one actually. If you, if you, um, were. Heart rate variability, monitor on or use an app or something for a period of time. You can identify patterns.

So for example, if you start to get ill, illness tends to be picked out, uh, quite well with heart rate variability tends to a drop in H I V just before and particularly when you are ill. And 

Mike: when you say just before you, you mean now it’s basically an increased susceptibility to illness or is this like when an illness is, it’s incubating in you and you just don’t know it yet 

Paul: e exactly that.

Yeah. So there, and that’s provided you’ve got a good baseline data. It, you know, if you get using H R V monitor for a couple of days, then all you’re doing is just measuring. Daily variability and noise, you need a, a baseline period. And then 

Mike: in that baseline period, how long is that normally? Uh, 

Paul: I would say at least, uh, a couple of weeks where your schedule’s relatively consistent so you’re not expecting any significant stresses.

So you’re not, for example, you don’t start training for a marathon, or you’re not starting to really aggressive diet or going for a stressful period at work or home to try and establish, um, a couple of weeks which are relatively normal. And then the algorithm of the monitor will be able to then compare that baseline against your subsequent variability and be able to identify sort of when there are, when there’s a, a meaningful change.

So h i v can be in a non-athletic context to help people identify kind of what periods where their body might be under more stress, in which case maybe they should back off certain elements of their life, for example. If their HIV is dropped for a couple of days and their stress score are increasing, then maybe it’s not a good idea to do a really hard training session 

Mike: and dropped by.

How much though? Well, it it 

Paul: depends on, on your, um, that’s what you need to do baseline period, because this, but, but maybe is there a 

Mike: percentage 

Paul: like not really. Cuz it, it, it’s, um, there are no cutoffs for it. You’ll get, you’ll get 10 athletes who are doing the same program, who are largely exposed to the same stressors and their HIV responses are different.

So that’s where the individualize, you can really compare h hiv scores cuz Yeah, it’s, it’s an inherently quite a noisy measure. So you have to have yeah. A good baseline period of collection before you. Using that information to kind of say, okay. And also picking upon what we mentioned previously about intuition, sometimes it kind of just supports what you already know.

So for example, if you’ve slept badly for three or four nights, then you’ve done a couple of heavy craving sessions, your HR V might get a lot worse or decrease, and it come into supports that you, you’ve just put your body into a lot more stress. So it’s an objective measure off that basically it’s, it’s taking the perception away and, and providing a 

Mike: number to it.

Yeah. And, and that, that’s also why I eventually stop tracking H R V as well, because the, a simple heuristic of, okay, it’s, it’s like life periodization works for training too. When you’re feeling. Push. And when you’re not feeling so good, back off and try, try to do at least enough to not move backward.

Like if, if things are really not, let’s say with training, right? You’re feeling great, everything’s good, and you’re doing three, four, or five intense workouts per week. Okay, good for you. All right, now you’re not feeling so good. So let’s back that off to no more than three and maybe those workouts are not as intense.

And if you’re sick, you’re gonna take a little bit of rest. And if things are really not good, then maybe just get in one or two strength training, good moderate intensity workouts per week just just to maintain what you’ve got until you feel better. 

Paul: Yeah. That, and that’s the utility of using H R V is that it can help sort of what I would say to, um, my clients and athletes that I work with is use it to kind of inform what you do, but not dictate it.

So for example, if, if you, um, have. Just don’t feel generally good and you’ve not slept well, for example. And then maybe look, um, back off your training because what, how you’re feeling and kind of your history leading into that is suggesting that you are maybe not gonna recover as well. And HIV usually trapped pretty well with that.

So sometimes it can be used as, um, called an educational talk where athletes have gone, we’ve looked at it and gone, it’s really sort of trending down here and you still did that planned session and then you got ill on the Saturday on in some cases, you know, like injury. It’s not to say that that cause that, but there’s, you know, it’s an association there.

So it can be used as like a, a way of kind of, Educating yourself on, on, um, sort of load management with training and um, yeah. Manipulating your training. Yeah, that makes 

Mike: sense. Kinda like a reality check. Yeah, exactly. Yeah. And, and a lot of people who, who take their fitness seriously, they’re more likely it’s harder to take a rest day or to take a, you know, take a deload week, give 

Paul: them some justification as well.

It’s almost like a doctor’s note, you know? It’s like, I really don’t feel great and my, but then the h i v is, is suggesting that I’m 

Mike: not recovered as well. It’s not just in my head. I’m not just making up an excuse to skip today’s workout . 

Paul: Yeah. So it’s supportive of that. But then I always say to people, you don’t have dictate train.

So if you feel really good and your agent, particularly if you are using those metrics of readiness, I wouldn’t let those dictate training at all because they could be giving you a sp sort of measurement and you’re going, okay, I’ll back off when in actual fat. You feel really good and good to go and your H r V is is kind of within its normal, uh, day-to-day variability, but it’s a useful measure.

But it’s, it’s like with the sleep stuff, it’s uh, not to become fixated on it and use as, as kind of a guide rather than something that dictates what you 

Mike: do. Yeah, yeah. And when I was paying attention to H R V, I was looking at trend in particular, cuz similar to the recovery, it wasn’t as stark, but there would be days when H R V was significantly lower than average, but I felt totally fine.

I slept fine. It seemed almost anomalous. And then a couple days later it’s just back to normal. And, and I didn’t change anything on those days, so not say it’s not a useful measurement, but at least in my experience personally, and, and I don’t think it was user error, I was using a Garmin device, like a, you know, you strap it on and same, same spot, same thing every day.

And there would just be some days that were. Better than usual for no apparent reason. And some days that were worse than usual for no apparent reason. But I did notice that if things were worse than usual consistently, yeah, that did seem to correlate with worse sleep or just a higher amount of stress than usual, including, so you have training stress and everything else, but individual readings, I was like, you know, I I’m not gonna change anything because my H R V came in 10% low today.

Yeah, exactly. Exactly. 

Paul: That you, you base, um, your decision how to use it on trends. Um, so either an awkward trend or a downward trend. If, if stress is getting greater rather than you can’t just take a one off reading and, and kind of let that dictate what you do or you shouldn’t do anyway, cuz um, yeah, it’s, there is inherent variability with the measurement from day to day and also just to, to finish up.

That’s why timing is critical. You can’t, um, if you’re gonna use. R v in your device study throughout the night, then just make sure that obviously you use the same device and if you’re doing it, I, I believe some devices like the Garmin where you put a belt on and you dictate when you don’t make sure you do it in the morning at the same time, um, so that you’re not adding extra variables, which you gonna, because pretty much everything affects H, HIV V, which is why it’s such a noisy 

Mike: measurement.

That makes sense. Yeah. Yeah. Um, in my case it was, you know, like an example for people, if I were to do it before I did my morning cardio session or after , that’s totally different. Before I had caffeine or after. Totally different. 

Paul: Yeah. Yeah. So can, whenever you using a bit of fitness tech, if you can standardize conditions and make it as much of a kind of like a lab test as you can.

Even with things like, I mean, you’ve talked about this on, um, your podcast before, like body mats and taking your weight. How about taking it the same time, the same if you’ve been to the bathroom before? And in tracking a weekly average and not taking kind of a snapshot, um, which is a big often mistake people make with, uh, when they’re tracking their body masses.

They only measure it once or twice a week, but you really should look at kind of a rolling average. Um, so they four, five day average from week to week to, to look at the trend, how variability is the same as that. Most physiological measurements have got al daily variability. So looking at them across the week at the same time of day and then averaging it is, is a way of kind of trying to reduce that 

Mike: era.

Yeah, that makes sense. Um, well, we’re coming, we’re just over an hour now and those are the major things that I wanted to discuss. We had a couple other things in our, uh, outline that maybe we could say for another discussion. Massage guns, compression things, IV drips, ice, ice baths, cryo also things I get asked about.

Um, but I think this is a good point to, to wrap up this discussion. Is there anything else regarding what we discussed that you wanted to, that’s still kind of bounce around your head? Anything that, uh, I should have asked? 

Paul: I suppose just from, from a consumer and, and what I often get asked in terms of is this any good?

My checklist would be, Claire, how long has it existed for? Has there been any validation studies done on it? And anyone can find that out. You using Google Scholar or PopMed? Look to see if there’s been a published study on it, which Creb is independent cuz a lot of companies will do their own kind of in-house white paper studies where surprised, surprised, you know, it’s really shows great accuracy 

Mike: or they’ll, they’ll work with just research groups that are unethical and or

Yeah. It’s in their financial interest to produce, uh, what the company wants and that, that. 

Paul: Yeah, and I mean, I’ve worked with them, actually done a validation study and the company, you know, was really great because they, you sign a contract at the start where you say, look, whatever we find from this device, we’re gonna publish it.

And they sign that off as well. So it’s independent. So there’s no, and they don’t see the data un until it’s ready for publication. So studies that have done like that, they’ll go through like an ethical approval process. So there’s a data sharing agreement, et cetera. And it just means that that research is of, of a good quality and it’s not, it’s less prone to, to bias from, in terms of publication bias of any publishing results, which show the device is really good.

So that will be my, um, the first thing to do. Have a look, uh, see what the litera is on our device, and then also, Before you start measuring something on a consistent basis to think yourself, what are the, what are the main purposes? Why am I measuring this? What, what do I hope to get outta it? You know, as I mentioned earlier, sometimes it could just be out of general interest, but if, for example, using, I don’t know, biological impedances and analyzer to track your body fat, having a good understanding that that has got an a amount of error associated with it, you’re not gonna get two weeks down the line and really annoyed because it’s not changing because.

You understand that the analyzer isn’t sensitive enough to pick that change up. So understanding some about the technology, um, can be really useful as well. Yeah, 

Mike: yeah. Great advice. Um, well, if there isn’t anything else, I think, uh, I think this is where we wrap this one up. Why don’t we finish with where people can find you and find your work and, uh, your book that you recently published, and anything else you want them to know about.


Paul: Thanks Mike. Uh, so I’ve, I’ve published, um, a couple of books. Um, the latest one is, uh, I. Mainly for personal trainers and people working in the fitness industry or, or interested in, in training and some of the topics we’ve discussed that covered in the book. And that’s, uh, advanced, uh, personal training summit to practice, uh, that there’s a second edition available, which, uh, you kind of contributed to Mike.

So thanks for that. I’m one of the chapters. 

Mike: Yeah, and I’ll say for, for people listening who are not trainers, but who enjoy these types of discussions, there’s a lot of just great evidence-based, very practical information in that book. So, um, , even though it is marketed toward trainers. I would say that if somebody is looking for evidence-based advice on how to improve their regimen, how to improve their strength training, how to improve their, their endurance training, how to combine those things effectively, how to improve their body composition, they’ll get some good practical advice from that book.

It, it’s not a book, I wouldn’t say. It’s just like, here’s how to be a good trainer. It’s, here’s how to improve all of these different things that a lot of people want to improve. 

Paul: Yeah. And in hindsight, I kind of, um, wish that they, marketing was more on the kind of, Consumer fitness enthusiasts, not necessarily a practitioner, because I’ve had quite a lot of feedback, um, on, you know, on social media, people messaging me saying, I don’t, I don’t actually work in the industry, but I’m really keen on, you know, training.

I’m enthusiastic and like the tracks that I, the topic we just talked about, about, um, tracking and monitoring, they found that really useful and, and applicable to their training. So that’s, yeah, it was really good to see. In terms of my other work, I, I do a regular sort of q and a. It’s, it is geared towards, uh, students that are studying sport and exercise site, but it’s open to the general public and, and.

You, you climb one of those on, um, working as a fitness entrepreneur and there’s various topics which have got quite broad applicability. So I usually advertise those on my social media channels, which, um, is, uh, I’ll probably best if I just include, it’s quite difficult way my handles work. Um, so I’ll maybe just include those in your show notes.


Mike: yeah, I’ll, there’ll be links and stuff. Uh, people can also just search your name, I’m assuming, to find you, right? 

Paul: Yeah, if, if you google my name sports scientist, you probably will come up with, um, my website and, and write this and the Rose links as well.

Mike: Cool. And and last name is h o u g h for, for people assign.

Paul: Yeah, it’s Hoff, spelled h o u g h. Um, and I’m not to be confused with, um, there’s a film director of the same name. Occasionally I’ll get a message. Ben did, did you direct this film as well? 

Mike: You know, , but yeah, we’re different people. , a Renaissance man. 

Paul: Yeah, I do. I do that in . That’s my side hustle. , yeah. Yeah. Into directing horror films as well. . All right. 

Mike: Well, uh, thanks again Paul. This is a great discussion and I look forward to the next one.

Paul:  Cool. Thanks and I really enjoyed the discussion. 

Mike: Well, I hope you liked this episode. I hope you found it helpful, and if you did subscribe to the show because it makes sure that you don’t miss new episodes.

And it also helps me because it increases the rankings of the show a little bit, which of course then makes it a little bit more easily found by other people who may like it just as much as you. And if you didn’t like something about this episode or about the show in general, or if you have, uh, ideas or suggestions or just feedback to share, shoot me an email, mike muscle for, muscle f o r, and let me know what I could do better or just, uh, what your thoughts are about maybe what you’d like to see me do in the future.

I read everything myself. I’m always looking for new ideas and constructive feedback. So thanks again for listening to this episode, and I hope to hear from you soon.

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