This is Part 2 of a 3-part series. Read Part 1 here.
It’s 7:18 A.M. and you’re greeted by the familiar sound of your alarm (for the third time this morning, because you hit snooze over and over). You begrudgingly get out of bed and instantly think about napping later. You barely slept again and the nights of poor rest are adding up: you’re fatigued and cranky, and your eyes are starting to resemble those of a raccoon. But, you trudge along and get ready anyway. When you look in the mirror, you not only see bags under your eyes, but you also see a body that makes you go “meh.” You’re not unhappy with your progress or how you look, but lately it’s been hard to push yourself in the gym and you’re looking less defined than you remember.
If you aren’t getting enough sleep each night, it is going to affect your performance and your appearance. Surely you care about at least one of those, so it is going to behoove you to get enough rest. We are all going to have nights where we can’t fall asleep or days where we just don’t have enough time, but many of us can cut out some crap and make enough time to sleep most nights. While I’m not here to talk to you how about blue light or watching TV before bed, I am going to tell you why sleep is so important in reaching your fitness goals.
While sufficient sleep is important for both gaining muscle and losing fat, my intention is to discuss its role in muscle building (hence the series title of "Why Can't I Grow"). However, most of the info I'm about to share will be helpful for anyone trying to stay healthy, so keep reading!
Before digging into all of the side effects that come with sleep deprivation, I’ll start with something direct: sleep deprivation results in increases in the secretion of catabolic hormones such as cortisol, and leads to changes in the secretion of anabolic hormones such as testosterone and insulin-like growth factor 1 (IGF-1) [1,2]. On top of that, these hormonal changes may reduce protein synthesis and impair muscle recovery . So, when you don’t get enough sleep, you’ll produce more catabolic (muscle degrading) hormones and your body won’t be producing the anabolic (muscle building) hormones in an ideal manner. That is bad news for anyone trying to pack on muscle. Or, if you’re a powerlifter who doesn’t necessarily care about aesthetics, you should know that even partial sleep deprivation can have a significant effect on your bench press and deadlift numbers .
If you still think you can overcome bad sleep after reading that... I would urge you to read on. While you can still progress in sub-optimal conditions, there is more to worry about than just “fewer gainz.” Not getting enough sleep can increase feelings of depression, confusion, fatigue, and anger . So along with suffering in the gym, you could end up suffering mentally, too. If you’re in school or starting a new job, you need sleep to not only prepare your brain for the next day, but also to help improve your ability to remember what you already learned that day . For athletes in team sports, this translates to being able to remember and recall plays or specific instances from film study.
On top of all that, it was found that sleep improves immune responses and that sleep deprivation can cause disruptions in the endocrine (hormone-related) rhythms in your body . One example of a hormone-related response to insufficient sleep is an imbalance in ghrelin and leptin, the two hunger-related hormones. Ghrelin makes you hungry, while leptin does the opposite… so of course, a lack of sleep increases ghrelin and decreases leptin . While maybe not a huge problem for those bulking up (and this isn’t how you should try to increase your appetite), this would be a nightmare for anyone trying to lose fat (such as all of the bodybuilders when the weather warms up). Also, as mentioned earlier, your body needs sleep to properly balance catabolic and anabolic hormone secretion. Or, if you’re into the much-harder-to-pronounce terms, the HPA (hypothalamic-pituitary-adrenal) and HPG (hypothalamic-pituitary-gonadal) axes need to be working together properly . Again, this is necessary for proper secretion of cortisol (the stress-hormone), testosterone, and IGF-1. Oh and before I forget, I also wanted to share that several studies support a potential link between chronic partial sleep loss and an increased risk of obesity and diabetes, which could be due to changes in glucose regulation (due to insulin resistance) or the results aforementioned appetite changes .
Okay, so you’ve made it this far, and you may be thinking “great, I definitely know why sleep is important now, but what can I do to act on all of this information?” Well, the first step is actually making time to sleep. Plenty of us aren’t even in bed for as long as we need to be asleep, so it makes sense to start there. You want at minimum 7 hours of sleep, but 7-9 hours is a much more ideal/normal amount (while anything over 9 hours is considered a “long” duration) .
Diet and meal composition has been widely investigated in regards to how they affect sleep, but there are some mixed findings. However, most have found that diets and meals higher in carbs tend to reduce the time it takes to fall asleep, although most allowed 1-4 hours between the the carb-rich meal and bedtime . Given some of the contradiction between studies, I would recommend testing this on your own to see what works.
There are also some supplements that can be used to enhance sleep, but again, effectiveness will vary between users. Also, my personal take is that it’s best to not rely on sleep aids every night (as tolerances and dependencies can be built up), but instead to just use them sparingly as needed. Since melatonin is the most popular one, I’ll start there. While it has been reported to reduce sleep-onset latency (the time it takes to fall asleep), that’s about the extent of the benefits. It is safe for short term use, but there isn’t any evidence that it is effective for most primary sleep disorders . It can also have side effects, such as headaches or daytime sleepiness (which I have personally experienced when taking melatonin). Aside from melatonin, tryptophan (yes, the stuff in turkey) has been shown improve sleep latency and subjective sleep quality at doses as low a 1 gram . Tryptophan is a precursor to 5-HT, which itself is a precursor to melatonin. However, supplementing with tryptophan will feel different than supplementing with melatonin. A third option is valerian, another somewhat popular sleep aid. It binds to GABA receptors and can promote calmness; however, most of the analysis shows a subjective (or self-reported, in this case) improvement in sleep quality, as opposed to having quantitative data . GABA itself is also sold as a sleep aid, but both can influence GH (growth hormone secretion), so tested athletes should be careful with their use of these two.
While most of us are aware that “sleep is good” for us, we tend to brush over the “why” aspect. With this article, my goal was to fill in that gap and show why adequate sleep is important. A quick Google search will tell you that the average American adult gets way less than 8 hours, and I’m sure your alarm clock makes you well aware of that most mornings, too. While all of this information is helpful to anyone trying to improve their health and well-being, it seems like the fitness world tends to ignore one of the most crucial aspects of muscle building (and fat loss). Every website or bodybuilder will tell you to eat right and work out hard, most forget to mention that you also need to sleep hard.
P.S. The source that I primarily reference in this article also has a tidbit about the benefits of naps, so I recommend taking a look at it yourself! The URL to it is in the reference.
 Halson, S.L. Sports Med (2014) 44(Suppl 1): 13. https://doi.org/10.1007/s40279-014-0147-0
 Dáttilo, M., Antunes, H.K., Medeiros, A., Neto, M.M., Souza, H.D., Tufik, S.B., & Mello, M.T. (2011). Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis. Medical hypotheses, 77 2, 220-2.