Among the many topics in the health and fitness sphere, those of sleep and rest are the less exciting ones.
Indeed, we often look for what sounds exciting: a new and promising supplement, a diet, a training program that promises the world, or something similar.
But when someone suggests that we place more attention on our sleep and rest habits, we discard the advice and look for another, more exciting solution.
But, the truth is, sleep and recovery are integral for our fitness and, to a large extent, our health. Today, we’ll go over why that is.
DOES SLEEP MATTER FOR MUSCLE GAIN?
Sleep deprivation directly undermines our muscle-building efforts, and the effect primarily seems to come from the adverse impact on our hormones. More specifically, the lack of sleep decreases levels of circulating testosterone and insulin-like growth factor 1 (IGF-1).
Research has firmly established that testosterone is among the most important hormones for muscle growth, development, and general anabolism. One of testosterone’s primary functions, as it relates to hypertrophy, is that it binds to androgen receptors, enters the nucleus of our cells, and increases protein synthesis rates.
Testosterone also inhibits the effects of specific proteins that inhibit the mTOR pathway (the fundamental energy pathway that affects muscle growth).
IGF-1 also works through the mTOR pathway and elevates muscle protein synthesis. The growth factor also plays a vital role in satellite cell recruitment and proliferation. Without it, we wouldn’t be able to accumulate myonuclei within our muscle cells as effectively.
So, sleep deprivation directly hinders two vital processes that result in muscle growth. But what’s even more interesting is that it doesn’t stop there.
Oh, yes. Next up, we have catabolism – the body’s neat way of breaking things (including muscle) down into their building blocks, so it can oxidize them for energy or use them in other processes.
For one, because sleep deprivation lowers testosterone, we allow myostatin (a protein that inhibits and regulates muscle growth) to stop the works of IGF-1 freely
Thanks to sleep deprivation, we often see an increase in cortisol levels. The hormone plays vital roles within the body, but having it chronically-elevated can lead to:
- Muscle protein breakdown
- Fat gain (particularly in the mid-section)
- Water retention
- High blood pressure
SLEEP AND FAT LOSS – IS THERE A LINK?
Sleep’s effects on our fat loss efforts are also incredibly nuanced. For one, because sleep deprivation lowers our testosterone, it can also negatively impact our basal metabolic rate (BMR). Research also suggests that higher testosterone makes it easier for the body to metabolize fat and harder for it to form new fat cells.
But things don’t stop there. One notable crossover design study from 2010 set out to determine the real-life effects of sleep deprivation on folks looking to lose weight.
In that study, ten middle-aged and overweight (but otherwise healthy) individuals were put through two conditions:
- They were put on a very low-calorie diet for two weeks and were allowed to stay in bed for 8.5 hours per night.
- They were put on the same diet for the same time but were only allowed to spend 5.5 hours in bed.
The two conditions were spaced at least three months apart. In the 8.5-hour state, the subjects slept for about 7 hours and 25 minutes. In the 5.5-hour condition, they slept, on average, 5 hours and 14 minutes.
In both cases, the subjects lost about 6.6 pounds of scale weight. In the 8.5-hour condition, they lost fat and lean tissue at about 50/50. In the 5.5-hour state, however, they lost fat and lean mass at about 20/80. Meaning, only a fifth of the total weight loss came from fat, and the remaining was lean tissue.
With everything else being the same, when subjects slept a couple of hours more, they lost more than twice the amount of fat.
CAN WE SLEEP OUR WAY TO BETTER ATHLETIC PERFORMANCE?
You’ve probably heard that elite athletes tend to sleep… a lot. In fact, some reportedly sleep for ten, eleven hours per night. That’s no coincidence.
The truth is, sleep seems to be vital for our physical abilities. If we want to maintain our performance, have productive workouts, and stimulate better results, we need to get enough sleep.
In studies, sleep deprivation has been shown to reduce:
- Reaction times
- Cognitive function
- Sprint performance
- Strength and power output
- Muscle recovery
Adequate sleep, on the other hand:
- Improves our endurance and prolongs time to exhaustion
- Post-training recovery, competitiveness, and success
- Strength and power
As a whole, sleep is vital four our health, physical performance, cognition, mood, and muscle-building and fat-losing abilities.
We often sacrifice it for other, seemingly more important things, such as catching another episode on Netflix, staying out with friends, working, or studying.
But, the truth is, if we want to elevate our health, fitness, and productivity, the best thing we can do is get more sleep. How much sleep, exactly?
Well, research is yet to give us a clear answer, and we all need different amounts. But, it seems that, for the average person, somewhere between seven and nine hours per night seem to be the sweet spot.