The Sleep-Recovery Connection: Why Gains Happen When You Rest

You have heard since you were a kid that sleep is important, but have you ever stopped
to consider the science behind it? Why do experts constantly push the importance of getting 8
hours of sleep? And most importantly- how on earth does sleep relate to gains? Here are 4
ways proper sleep contributes to muscle growth and improvement in performance:
1. Triggers cellular repair
According to a review published in the International Journal of Endocrinology, the body is
least metabolically active during N3 (deep sleep).
1 Non-REM sleep, such as the N3 period is
associated with lower metabolic rate and brain temperature. During normal sleep, the metabolic
rate reduces by around 15%, with the lowest rate occurring in the morning. Why is this a good
thing? This is the period in which the body recovers from the stresses of being awake and being
in REM sleep. It is imperative for the body to reach this stage of sleep in adequate amounts in
order to allow the body to repair damage. This stage is the time for regrowing tissue, building
bone and muscle, and strengthening the immune system.
2 Without sufficient deep sleep, the
body’s ability to recover, grow, and adapt is compromised- ultimately limiting physical
performance.
2. Promotes protein synthesis
Skeletal muscle is a primary regulator of metabolism. Sleep restriction, even for periods
of less than a week, significantly affects muscle health and impairs muscle function. One study
in 2021 found that a single night of total sleep deprivation was sufficient to induce anabolic
resistance and a procatabolic environment.
3
In other words, just one night without sleep can
make it harder for your body to build muscle, and easier for it to break it down. This impairment
in muscle protein metabolism may be explained by the changes in the hormonal environment.
3. Activates growth hormone
While growth hormone (GH) is more commonly known for its importance in growth
during childhood, it plays crucial roles in adulthood as well, including energy and fat metabolism,
body composition, and physical function. GH stimulates resting energy expenditure, allowing the
body to burn more calories at rest.
4
It also plays an important role in muscle growth and repair.
What does this have to do with sleep? Deep sleep triggers the release of growth hormone. With
a proper amount of deep sleep, your body will more efficiently burn fat, build muscle, and stay
energized due to a boost of growth hormone levels.
4. Affects overall mood, energy, and wellbeing
Sleep and moods are closely connected. Many studies have linked sleep deprivation to
negative moods including irritability, frustration, and anger. Poor sleep has been found to
increase negative emotional responses to stressors.
5 Along with these emotional responses,
loss of sleep can result in less energy for exercise and physical activity. While feeling grumpy or
exhausted, you may find it more challenging to push yourself during a workout, or maybe even
have a hard time getting to the gym. The good news is that sufficient sleep has been associated
with improvements in strength, power, and endurance. A consistent routine of a good night's
sleep can improve your energy levels, mood, workout consistency, and performance!
The bottom line: sleep is crucial. Chronic sleep deprivation is negatively affecting not
only your health, but your fitness gains as well. Without proper rest, your body can’t repair,
recover, or grow efficiently- no matter how much time and effort you are spending in the gym.
Prioritizing quality sleep is a factor that often goes overlooked, but is just as important as your
workout routine and nutrition when it comes to reaching your fitness goals.