Fix This If You Want to Double Fat Loss (Not Muscle)

Most people think that sleep is just about feeling rested. If you can function on 5-6 hours, if you can still get your workouts in, if the scale is going down, then you assume that you're fine. But when I dug into the human research, I kept seeing something quite disturbing. Short sleep doesn't just make you tired. It changes what your body does with muscle, fat, testosterone, and your blood sugar. You're going to be shocked by some of the findings about what 4-5 hours of sleep does to young healthy individuals. The most shocking finding comes from this 2010 study. They had overweight individuals on a weight loss diet for 2 weeks, and during that time, they slept either 5.5 hours or 8.5 hours. Everyone lost around 3 kg of weight, but what they lost was dramatically different. Sleeping 5.5 hours resulted in 0.6 kg of fat loss and 2.4 kg of muscle loss. It means they lost 80% of those 3 kg as muscle and only 20% as fat. Sleeping 8.5 hours resulted in 1.4 kg of fat loss and 1.5 kg of muscle loss. They lost pretty much 50-50 muscle and fat, which is quite normal for regular weight loss without exercise. It means that if you're putting a lot of effort into your workouts, but you're not sleeping enough, you might end up losing more muscle than fat. Losing too much muscle will make it harder for you to maintain your metabolic health, not to mention the risk of frailty later in life. Not only do you lose more muscle with sleep restriction, but it's also harder for you to build muscle. In this 2020 study on healthy young men, 5 nights of severe sleep restriction, 4 hours a night, reduced myofibrillar protein synthesis by 19%. Performing 3 sessions of high-intensity interval exercise during sleep restriction completely prevented this reduction. The anabolic stimulus from this exercise was strong enough to maintain integrated protein synthesis over 5 days, despite severe sleep restriction. Now, the takeaway isn't that you should exercise whenever you're sleep-restricted. The takeaway is to not sleep 4 hours in the first place, because exercise after proper nights of sleep would raise protein synthesis above baseline, whereas in this study, exercise after sleep restriction just restored the protein synthesis to the baseline. For muscle growth and fat loss, you also benefit from testosterone, and sleep loss reduces testosterone. Sleeping 9 hours vs 5 hours for 1 week reduced testosterone by 10-15%. In young men, that's still within the normal range. Interestingly, their cortisol levels didn't change during sleep restriction, which means that the reason their testosterone dropped wasn't because of cortisol, but something else. I hope you're starting to see that sleep restriction wrecks your gains. It makes it harder to build muscle, and you're more likely to lose muscle. Reviews on sleep deprivation on strength parameters have shown that muscle strength on 1 rep max tests doesn't decrease significantly after a single night of short sleep, but it does after several nights. So if you're chronically sleep deprived, you're weaker than if you were to be when getting adequate sleep. Power output and maximal voluntary contraction do decrease significantly even after a single night of sleep loss. That's driven mostly by central nervous system fatigue, which appears to be more affected than pure muscle contractile capacity. Indeed, 1 night of 50% sleep loss reduced sprint performance by 2-4% in elite athletes. Now, 2-4% isn't that significant for the general population, but it's quite significant for athletes, because for them, every single percentage matters. So a single night of bad sleep doesn't affect your performance that much, at least if you're in a general population and you're not an athlete. But if you're chronically sleep deprived, then you're certainly going to be weaker and slower. I want to take a quick break to tell you about the Bonchard Infrared Sonar Blankets, my go-to way of getting 20-minute sonar sessions on the go without needing to spend an hour to warm up a regular sonar. Taking the sonar is, in my opinion, one of the best things for your overall health and heart function. Studies show that taking the sonar regularly is associated with 63% lower risk of sudden cardiac death, 63% reduced heart disease mortality, 46% lower risk of hypertension, and 40% reduced all-cause mortality. This is mediated by an increase in body temperature and increased heart rate that mimic a cardiovascular workout, while at the same time improving arterial stiffness, endothelial function, blood flow, immune system function, blood pressure, and metabolic health. It doesn't matter if it's a traditional wooden sonar, an infrared sonar, an infrared sonar blanket, or anything else that elevates your body temperature above what's normal. It warms up in two minutes to the optimal temperature of 70 degrees Celsius and it's low in EMF. You can get a 15% discount by heading over to www.bonchard.com forward slash seamlunt and use the code SEAM for a 15% discount. All right, back to the video. We also have to talk about the effects of sleep deprivation on your metabolic health and insulin sensitivity, because insulin sensitivity makes it easier for you to build muscle because insulin is an anabolic hormone. Insulin is one of the hormones that helps with muscle glycogen storage and it also directly stimulates protein synthesis and mTOR activation. It's no surprise that sleep restriction reduces insulin sensitivity. One week of sleep restriction, five hours a night, reduced insulin sensitivity by 11 to 20% in healthy young men. And reducing sleep by 1.3 to 1.5 hours per night for six weeks, so cutting it down to 6.2 hours per night on average, impaired insulin sensitivity by about 15 to 20% in healthy women. Restricting sleep to 4 hours a night for just 6 nights has been seen to reduce glucose tolerance by 40% in healthy 20 year olds. These are healthy young people, who see their blood sugar and insulin sensitivity markers brought down to pre-diabetic levels, even after a single night of short sleep. Imagine if you're sleeping 4 to 5 hours every night. Over the course of years, you can slowly become pre-diabetic. The tricky part is that not only does your insulin sensitivity decrease, your desire to eat more junk food increases. Two days of sleeping 4 hours has been seen to alter appetite hormones in a way that promotes hunger and potentially weight gain. An important part is that in this study, calorie intake was controlled, so these changes were not driven by overeating itself. They saw an 18% reduction in leptin, the satiety hormone, a 28% increase in ghrelin, the hunger hormone, a 23% increase in appetite, and 33 to 45% increase in cravings for junk food. It's a vicious cycle. You sleep short, you get more cravings, you want to eat more, you eat more junk food, you have worse insulin sensitivity, which makes it more likely that you store the food as fat, not muscle, and you'll end up losing more muscle because of the sleep restriction. So it's a vicious cycle. The message of this video is simple but often misheard. Sleep restriction is not only bad for your longevity, but also bad for your body composition. Now, I'm not going to go into the details of how to improve your sleep in this video, but you should know that sleep at least 7 hours. If you want to know how I got my sleep scores to 100 with basic sleep optimization, then check out this video next.