man wearing blue shirt sleeping in bed

Do you ever feel like you’re not making the progress you should be? You’re training hard, programming intelligently, and eating well, but results often come slowly.

What could the problem be? Why do some people seem to make such good progress where you fight for every kilo on the bench press?

It all relates to one thing…

How Sleep Impacts Our Performance And Training Results
Sleep impacts us on three big fronts. Let’s take a look at each.

1. Sleep and Muscle Growth
Sleep hinders muscle growth and athletic abilities in two ways. First, sleep deprivation lowers two essential hormones: insulin-like growth factor 1 (IGF-1) and testosterone

IGF-1 has important functions inside the body, one of which is recruiting and increasing the number of satellite cells. The hormone works through the mTOR pathway to elevate muscle protein synthesis and improve our muscles’ potential for growth.

As you’re probably familiar with, testosterone is also essential for muscle growth and development. The powerful androgenic hormone is responsible for muscle protein synthesis and can hinder proteins that inhibit mTOR function. Testosterone is so powerful that injecting supraphysiological amounts can result in muscle growth even without training.

Second, not getting enough sleep raises levels of cortisol - the stress hormone. Spikes and drops in cortisol are normal and beneficial. But not sleeping enough leads to chronic elevation, which can lead to:

  • Quicker muscle protein breakdown
  • Drop in protein synthesis rates
  • Water retention
2. Sleep and Fat Loss

A study from 2010 did a beautiful job of illustrating how sleep deprivation impacts fat loss. In that study, ten overweight but otherwise healthy individuals had to go through two conditions:

  1. Spend 8.5 hours in bed per night and diet for two weeks
  2. Spend 5.5 hours in bed per night and diet for two weeks

The two conditions were spread at least three months apart, and everything was the same aside from sleep duration.

When subjects got to sleep for 8.5 hours per night, they usually slept for 7 hours and 25 minutes. When they could only spend 5.5 hours in bed per night, they slept an average of 5 hours and 14 minutes.

Both conditions lost 3 kilograms in two weeks. When they got to sleep for over seven hours, subjects lost fat and muscle at a 50/50 ratio. But when they only got to sleep 5.5 hours per night, they lost fat and muscle at a 20/80 ratio. With everything else the same, subjects saw considerable differences in fat and muscle loss.

3. Sleep and Athletic Performance
The relationship between sleep and athletic performance is nuanced, and we have to look at many different angles. For one, we have the direct effects of sleep deprivation on fat loss and muscle gain. Both of these can impact our performance, motivation, and overall training fulfilment.

Second, while we don’t have much data to work with, sleep appears to hinder power output, motivation, and cognitive function, all of which play a role in athletic performance.

Third, sleep deprivation makes us less alert, more impulsive, and more irritable. As a result, we might be more likely to skip a workout or make poor nutritional choices.

Together, the many adverse effects of sleep deprivation can hinder your athletic performance, productivity, motivation, and cognitive function.

September 17, 2021 — Daniel Felstein

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