Listen on Apple Podcasts | Listen on Spotify | Listen on YouTube


Could disrupting your sleep cycle on weekends sabotage your weight loss efforts? 

Does fish oil supplementation play a significant role in muscle strength gains? 

Can cooling your palms between sets actually boost your reps?

In this episode, we’ll explore the latest research studies that explore these intriguing questions.

This podcast is another installment in my Research Review series of episodes, where I give you concise and practical takeaways from studies that I think are interesting and that can help us gain muscle and strength faster, lose fat faster, perform better athletically, feel better, live longer, or get and stay healthier. 

There is a ton of scientific research that gets published every year, and even if you narrow your focus to fitness research, it would still take several lifetimes to unravel the hairball of studies on nutrition, training, supplementation, and related fields. 

That’s why my team and I put a lot of time into reviewing, dissecting, and describing scientific studies in articles, podcasts, and books. 

Oh and if you like this type of episode, let me know. Send me an email ([email protected]) or direct message me on Instagram (@muscleforlifefitness). And if you don’t like it, let me know that too or how you think it could be better.


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

1:19 – Can staying up on weekends affect weight loss?

5:46 – Can taking fish oil help with strength gains?

13:27 – My free quiz to answer all your diet questions.

14:57 – Can cooling your palms in-between reps improve reps?

Mentioned on the Show:

Take this free quiz to get science-based answers to all of your diet questions.


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


Hello and welcome to Muscle for Life. I’m Mike Matthews. Thank you for joining me today for another installment in my intermittent series of research review episodes where I take three topics that I’ve been reading research about and that I think are interesting or topical, or that I think you, my lovely listener, may find interesting.

Usually something that I haven’t already beaten to death a million times before, which after doing about a thousand episodes, over a thousand episodes of this podcast, now it takes a little bit of doing to find something that I haven’t already written or spoken about extensively. And so in these research review episodes, three topics, and I’m going to be discussing some research on each.

And in today’s episode, the first topic I am going to address is, Staying up late on the weekends, and particularly if that can affect your weight loss. That’s a question that I get now. And then, does staying up late on the weekends get in the way of weight loss in one way or another? Then I’m gonna talk about fish oil and muscle growth and strength gain.

Can taking fish oil help you gain muscle and strength faster? And finally, I’m gonna talk about palm cooling. Can you boost your performance in the gym by cooling your palms? Okay, so let’s start with staying up late on the weekends. Can that hinder weight loss? So this takes us into the field of chrono nutrition, which is the exploration of how changes in sleep can influence diet and how changes in diet can impact sleep.

And there are many. Theories about meal timing as it relates to chrono nutrition and other things. You’ve probably heard that eating breakfast soon after you wake up, kind of kickstarts your metabolism, tells your metabolism that it’s, it’s time to get going. You might’ve heard that eating before. Bed can increase fat gain, especially if you eat carbs before bed.

And those ideas and many other ideas like those are false, but there is some interplay between our sleep and our eating patterns. Research shows that there is a link between nutrition and circadian biology that we can influence our body’s circadian rhythms with our. Eating habits and our body’s circadian rhythms can also impact our eating habits.

So it’s a two-way street here. And our circadian rhythms impact many other things too. They impact our digestion, our nutrient metabolism, our appetite regulation, hormone secretion, and others. Things. And that is why scientists continue to study chrono nutrition. They continue to look into how changes in sleep can influence the diet, and then how changes in our diet can influence our sleep.

And one area of particular interest in this field is the connection between eating behavior and what is referred to as social jet lag, and that refers to the lethargic feeling you have come Monday after. The weekend when social events upset your usual sleep and wake times. And this is of particular interest to scientists because studies show that social jet lag can significantly affect your eating habits and your metabolic health.

So for example, in a 2022 review conducted by scientists at uu haha, university of Medicine and Pharmacy researchers found that people who don’t have a consistent bedtime weather because of social jet lag or just day-to-day inconsistency when compared. Are to people who go to bed at the same time every night or more or less, the same time.

The ones who have an inconsistent schedule tend to eat a less healthy diet, so they eat fewer fruits, fewer vegetables, fewer whole grains, fewer legumes, more sugar, more soda, and unlike people with a regular bedtime, those with social jet lag also usually experience more hunger. And more cravings for calorie dense foods even after they’ve eaten.

The researchers also found that in studies of obese people, those with social jet lag typically ate more calories, carbs and fat than people without social jet lag. Now, we have to keep in mind that this was observational research, so it can’t be used to establish causation. It can’t be used to say that social jet lag.

Causes those things, it may, and the observational research has indicated that there is an association, there is a relationship there. Those, those things are correlated, but we can’t say for sure if social jet lag is causing those things. That said, the weight of the overall evidence on the matter does seem to indicate that going to bed around the same time every night probably will.

Or at least may help you make better food choices. Eat fewer calories, better control your appetite, and that’s likely why several studies have shown that people who have a regular bedtime are less likely to be overweight or obese than people who go to bed at different times every night. Now, the terms social jet lag is aptt because socializing especially.

Nighttime socializing is anathema to keeping a consistent sleep schedule, so you have to find the balance that works for you. It is okay to occasionally break your routine on the weekends, but just know that the more often you do that, the more difficult it can become to control your hunger, to control your appetite, to make good food choices.

So the key takeaway here is try to go to bed at the same time on most nights, including the weekends. Try to make that the rule rather than the exception, and allow yourself the occasional exception. It’s okay if you wanna stay up later now and then, but the more often you do that, the harder it may become to achieve and maintain your health and fitness goals.

Okay, let’s move on now to fish oil and muscle and strength gain. Can taking fish oil help you gain muscle and strength faster? And if you know anything about fish oil, if you take fish oil, it’s probably because you know of research that indicates that it can improve your heart health, it can improve your brain health, it can improve your joint health.

And the weight of the evidence is that fish oil is indeed effective on those fronts. Of course, it still is supplementary, but it is an effective way to get omega three fatty acids. And over the last few years, evidence has been emerging that fish oil may enhance muscle and strength gain. And this is because the E P A and D H A in fish oil, so the omega three fatty acids, the two really important ones that we’re going for e p A and D H A, they appear to boost muscle protein.

Teen synthesis, which is the synthesis, the creation of new muscle proteins, which then would create a more anabolic environment in your body. That doesn’t mean that you can take fish oil and get bigger and stronger, but the more muscle protein synthesis that occurs after you train. The better for the purposes of muscle hypertrophy, and this isn’t actually a new claim.

There is research going back to the seventies showing that fish oil supplementation may be able to increase muscle protein synthesis. There are other studies that suggest that fish oil can impact muscle fiber type can impact neuromuscular recruitment, muscle protein breakdown rates. Insulin signaling, uh, different mechanisms that could further enhance muscle and strength gains.

And while arguments like those and proposed mechanisms like those and research suggesting that those are real effects occurring when you take fish oil are interesting. If we look at results from studies on fish oil’s, actual impact on muscle growth and strength gain. It tends to be inconsistent. Some studies show positive benefits.

Other studies show no benefits whatsoever. But most of the studies conducted so far have some pretty major methodological flaws, and that means that we just don’t really know whether the inconsistency are a reflection of some deficiency in fish oil or it’s a deficiency. In the research and if we had more better research, we would see consistency, whether it is positive or negative.

And that ambiguity is what prompted researchers at Baylor University to undertake their own research on the matter. Their goal was to investigate whether. Fish oil improves body composition and strength in a well conducted trial. And so what the researchers did is they split 21 men and women into two groups.

One group took four and a half grams of fish oil every day, which provided about 2.3 grams of E P A and 1.6 grams of d h a. And the other group took a placebo. And they did those things for 10 weeks, both groups, and that is a good amount of fish oil that is about two to three times more than the generally recommended dose for just maintaining health, which would probably be one to two grams per day of E p A and D H a combined.

But we know from research on joint health and fish oil, for example, that if you want. To help your joints out, you’re gonna have to take a bit more than just the bare minimum that’s needed to maintain health. And so I was happy to see that the researchers used a larger dose for this study because if fish oil can indeed enhance body composition, it probably will require a larger dose.

And so anyway, the participants in this study, they didn’t just take fish oil, they also did strength training. They did three full body workouts, basically three to four sets of a number of exercises ranging from a squat or a leg press, or a leg extension, or a leg curl to a bench press, shoulder press, seated cable, row, lap pull down, and the results of the study showed.

That the fish oil group experienced larger increases in their bench. Press one rep max, so the fish oil group gained about 24 pounds on their bench press on average versus about 14 pounds in the placebo group on average and squat one RMMs were a bit better. The increases in the fish oil group about 53 pounds on average versus about 41 pounds on average in the placebo group.

And the fish oil group also tended to lose slightly more fat and gain a little. Little bit more lean body mass, which is a proxy for muscle, but it doesn’t necessarily mean lean contractile muscle tissue. It can also be intramuscular fluid, for example. That would register as lean mass. But the body composition changes in this study where, Pretty small.

And so those findings might not sound all that exciting. Might not make you want to rush out and buy my fish oil supplement Triton, but they do suggest that fish oil is a win-win for. Weightlifters. We know that getting enough omega threes is important for health and therefore fish oil can improve health.

We know from other research that supplementing with fish oil is likely to improve performance, and this study does represent some evidence that it can help you build muscle and maybe even lose fat. Faster. Now, we do have to keep in mind of course, that this is just one study. It was a well conducted study, but it is just one study, so it’s not enough evidence to draw firm conclusions about how fish oil can affect strength, gain, muscle growth, and fat loss.

And so I think it is fair to say that fish oil shows potential in this regard, but it should be considered speculative. Oh, and one other point that’s worth mentioning, just given the dose in this study, which again was about 4.5 grams of fish oil per day, which provided about 2.3 grams of V P A and 1.6 grams of d h a, some experts would be concerned about that dose, especially if it were a regular.

Thing because of some research that suggests that taking a lot of fish oil, taking a high daily dose of omega threes may increase your risk of developing cardiovascular issues. But on the other hand, many experts are skeptical that that is something that we need to worry about because scientists are still trying to puzzle out the connection between high daily doses of fish oil and the potential risk of cardiovascular problems.

It’s certainly not clear that fish oil is causing those problems or that a high daily dose of Omega three fatty acids is causing those problems. And so anyway, if you want to play it maximally safe with your fish oil supplementation, most research suggests. That a combined intake of about 1.8 grams of E P A and D H A per day is, or that’s about three grams of fish oil, depending on what product you’re using, is more than enough for general health.

It also should reduce muscle soreness, and it should reduce inflammation in your joints. At that level, you should notice those effects, whereas with a combined E P A and D H a intake of say, 500 milligrams per day is probably not enough to reduce muscle soreness or improve joint health or. Function. And lastly, I did mention I have a fish oil supplement that I take every day myself.

It’s called Tritton, and if you want to learn more about it, you can find it [email protected], B U Y L E G I O How many calories should you eat to reach your fitness goals faster? What about your macros? What types of food should you eat, and how many meals should you eat every day? Well, I created a free 62nd diet quiz that’ll answer those questions for you and others, including how much alcohol you should drink, whether you should eat more fatty fish to get enough omega three fatty acids.

What supplements are worth taking and why? And more to take the quiz and get your free personalized diet plan. Go to Muscle for Life Show slash diet quiz, muscle fo life show slash diet quiz now answer the questions and learn what you need to do in the kitchen to lose fat, build muscle, and get healthy.

Okay. The last topic I want to discuss in today’s episode is a biohacking technique du jour, and that is palm cooling hot topic these days because according to several sports teams like the San Francisco 49 ERs, the Oakland Raiders, the Manchester United FC Soccer Team, as well as well-known people in the evidence-based fitness community like Dr.

Andrew. Huberman cooling your palms or the soles of your feet while you rest in between sets of weightlifting is going to boost your performance. Now, how the hell is that supposed to work? Well, the purported mechanism is it lowers the temperature of your blood and it. Blocks, pain signals to your brain, and those things allow you to do more reps in the subsequent sets than you otherwise could.

And if that were true, that would be significant because the more reps you do, the more muscle you stand to gain and the better you will perform. Basically any athletic endeavor, at least over time. Not everyone is sold on this though. According to some scientists, much of the evidence supporting palm cooling fails the good old smell test.

For example, in two influential studies that were conducted at the University of New Mexico, neither the authors nor the participants were blind to the studies protocols, which makes it likely that bias colored the results somehow in some way. When the researchers know. Who is getting the treatment and who is getting the control.

And when the participants know if they are getting the treatment or they are getting the control, that can lead to biased results. Additionally, the researchers in these studies used imprecise methods to collect muscle activation data, so that makes their interpretation of the figures questionable. Then there is another study that is often used as scientific evidence of how great palm cooling is.

In this case, it was conducted by scientists at Stanford University, and the researchers claimed that Palm Cooling allowed one participant to do 466 pull-ups across 10 sets. So like 47 ish pull-ups per set, suspiciously high. I wonder how strict those reps were. Are we talking about pull-ups or CrossFit kipping and then of course there are some unreviewed and unpublished.

Studies that were conducted by a cooling MIT manufacturer, uh, conflict of interest to anyone. And in these cases, athletes allegedly increased their DIP performance by 200%. Their bench press performance by 31%, pull up performance by 516% after just two to six weeks of palm cooling between sets. Will that be cash or credit?

Now before you rush off and buy some cooling mitts, let’s talk about research on the other side of the coin. Let’s talk about research that has failed to show benefits. So there’s a study that was conducted by scientists at Galoshes University, in this case, squatters who chilled their feet. In between sets did the same number of reps across three sets as those who simply rested.

And then there was a study published in the International Journal of Exercise Science, and in this case, weightlifters did the same number of biceps curls, whether they cooled their palms, neck, biceps, or face between sets. Not. And there was another trial that was spurred by all of this confusion, and this was conducted by scientists at Ulster University.

And what these researchers wanted to do was mimic previous research on palm cooling using more rigorous. Methods. That way they’d be able to discern whether flawed methodologies and poor data handling had over egged the results. Uh, maybe a little bit of some of this prior research or whether palm cooling actually has merit.

And so in this case, the scientists had 11 experienced weightlifters do three workouts, uh, four days apart. And in each workout, the weightlifters did four sets of bench press with 80% of their one rep max to failure. And then they rested three minutes in between sets and during the rest periods. The weightlifters spent one minute with their hands in a cooling device and in one workout the device cooled their palms to 50 degrees Fahrenheit in another to about 60 degrees Fahrenheit.

And in another, it kept them at the 82 degree Fahrenheit Control. Condition and the results showed that palm cooling at 50 or 60 degrees Fahrenheit did not affect bench press performance. It did not increase the number of reps the weightlifters could do set on set. It did not improve power output. It did not change how active the pecs, Dels, or triceps were performing the bench press it.

Basically did nothing. And so while this one study does not put all the nails in the coffin of palm cooling, it does deliver a blow to its credibility. It is a reason to not waste your money or your time with mitt cooling devices or anything else that cools your hands or cools your feet in between sets.

Now, if you just want to do it yourself, maybe because you saw one of the Stanford University researchers claim that Palm cooling is. Equal to or substantially better than steroids, and that’s me quoting equal to or substantially better than steroids. Okay? And if that’s encouraging to you and you think, well, shit, if it’s 10% as effective as steroids, I want to see for myself, then go for it.

It’s not going to harm you. It’s not going to decrease performance. There’s no evidence of that. But it is not a slam dunk like creatine is. Yeah, some people don’t respond to creatine, but most people do, and most people experience significant performance benefits by just taking three to five grams of creatine monohydrate every day.

And so if you’re not doing that yet, just start there. Spend the money that you might spend on a cooling mitt or some other type of device and, and just buy some creatine monohydrate. 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, [email protected], 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.

View Complete Transcript