Importance of sleep when training

We spend approximately ⅓ of our lives asleep — but what actually happens during sleep, and why is it needed for exercise recovery?

From a young age, we’re told the importance of a good night’s rest. And while most of us typically get anywhere from 7 to 9 hours of sleep each night, many of us don’t know just how important sleep is.

It becomes even more important as an athlete.

Chances are, you’ve had your fair share of nights when you just couldn’t sleep. The next day, you feel the effects of sleep deprivation. You feel restless, struggle to concentrate, skip training, and are more likely to make poor nutritional choices.

Sleep and exercise recovery go hand in hand — if you don’t get enough sleep, you’ll likely see a decline in training and recovery performance.

Whether you’re into endurance sports such as cycling, running, or ultrarunning, or you just enjoy lifting weights a few times a week, you need plenty of quality sleep each night.

Why is sleep important?

According to the CDC, 1 in 3 adults do not get enough sleep.

However, sleep is important for virtually all bodily functions — if you get Insufficient sleep, you’ll soon experience the side effects.

To better explain how sleep works, we need to break down the 4 sleep stages:

Awake — time spent before falling asleep and time spent in bed.
Light sleep — your muscles relax, heart rate decreases, and body temperature drops.
Deep sleep — growth hormone is released, energy stores replenish, and memories are processed.
Rapid eye movement (REM) sleep, known for its vivid dreams, focuses on memory, learning, and problem-solving.

It takes approximately 90 minutes to complete a full sleep cycle, which includes stages 1 to 4. During the night, you’ll typically repeat the cycle 4 to 6 times.

Repeating these cycles is important for rest and recovery. Getting enough sleep and completing the sleep stages from start to finish helps process memories, repair muscle tissue, and improve cognitive function (as well as many other things).

The relationship between sleep and exercise recovery

All sleep stages play a crucial role in the body, but deep sleep is especially important for athletes.

During deep sleep, growth hormone is released — this repairs damaged muscle tissue. Also, the body replenishes energy stores and sends oxygen and nutrients to the muscles and body to regenerate cells.

If you don’t get enough sleep, you’re more likely to feel fatigued and sore the day after a workout.

Not getting enough sleep may also increase your risk of cognitive decline. That could mean lapses in concentration and memory, losing your train of thought, or finding it hard to make decisions.

This is one of many side effects of sleep deprivation that not only impacts your recovery from exercise but also day-to-day activities.

What happens if you don’t get enough sleep?

The big question: What happens if you don’t get adequate quality sleep? Research shows that a short-term lack of sleep can cause:

Stress
Pain
Depression and anxiety
Cognition and memory issues
Poor performance
Inadequate recovery between workouts
Worsened mental health

Long-term effects of sleep loss or disturbed sleep can cause more severe side effects, including a weakened immune system, various metabolic issues, such as weight gain, type 2 diabetes, high blood pressure, stroke, and heart disease.

For athletes, sleep deprivation impacts their ability to perform at their best. It increases injury risk because recovery suffers. Develop good sleep habits and treat sleep with the same attention you do to your training to improve athletic performance and recovery.

What are the best ways to improve sleep quality?

If you’re putting in plenty of miles on the bike and a few strength training sessions a week, you’ll know just how important sleep is.

Firstly, you may find yourself wanting to sleep more, perhaps feeling more lethargic than usual. Oh, and you’ve probably indulged in 1 or 2 midday naps — they’re great, right?

But to get the most out of your training, whether running, cycling, weight lifting, or any other workout, you need to get on top of your sleep — that means getting enough quality sleep as often as you can.

There is no set number of hours to aim for — some people like 7 hours of sleep while others get 9 or 10.

To help you get better quality sleep, focus on improving your sleep hygiene — this is habits and behaviours surrounding sleep.

Here's how to get started:

Wake up and go to bed at the same time every day
Increase light exposure in the early part of the day (and limit exposure in the evening)
Avoid drinking caffeine too late in the day
Set a bedtime routine
Do not use your smartphone in the bedroom
Sleep in a cool environment (open windows, use a fan or AC)
Have a hot bath or shower 1-2 hours before bed

FAQs

Can taking sports supplements or other products help me sleep better?

This is a tricky topic — there are sleep supplements, but it’s always recommended to improve your sleep hygiene before experimenting with supplements. If you do want to try sleep supplements, we recommend consulting with a doctor beforehand.

Does sleep help recover from exercise?

Yes! Growth hormone is released during sleep, which repairs the muscles and cells. Blood is also sent to the muscles, packed full of oxygen and essential nutrients to support recovery.

How does sleep relate to fitness?

Sleep allows the muscles and energy stores to replenish. This stimulates muscle and cell growth and allows you to improve your fitness.

Does sleeping a lot help with muscle recovery?

Getting more sleep can help with muscle recovery. This is because the body produces growth hormone, which repairs muscle cells. Try to get consistent, quality sleep every night for the best results.

How does sleep affect exercise recovery?

Sleep supports muscle repair, hormone balance, and energy restoration — all essential for recovery and overall health. Deep sleep promotes growth hormone release, which aids muscle healing and recovery. Poor sleep can slow recovery and impact performance. Aim for 7–9 hours per night (as a rough guide).

Sleep and exercise recovery: What you need to know