Everything you need to know about sport and sleep

What is the purpose of sleep?

If we spend nearly a third of our lives sleeping, it’s because sleep is absolutely essential to our proper functioning. It may seem like a lot, but it’s indispensable. Even if we haven’t unlocked all of sleep’s secrets, we know it’s crucial for our health.

• It strengthens the immune system,  lack of sleep can make you four times more likely to catch a cold.
• It promotes short- and long-term memory consolidation.
• It’s also the ultimate time for rest and cellular regeneration. While we sleep, muscles replenish their glycogen stores, ensuring a steady energy supply during waking hours.
• During deep sleep, the body releases growth hormones (also called somatotropins), which stimulate cell growth and reproduction.

How does sleep work?

A good night’s sleep usually consists of 3 to 5 cycles of 90 minutes, depending on the person. During slow-wave sleep, metabolism slows down: muscles relax, body temperature drops, and both heart rate and blood pressure decrease. This stage goes from the transition phase (falling asleep) to light sleep, then to deeper sleep, until the paradoxical or REM phase.

During REM sleep, the body is completely relaxed, but brain activity is almost as high as when awake. It’s called REM (Rapid Eye Movement) sleep because of the quick eye movements, irregular heartbeat, and fluctuating body temperature. This is when dreaming occurs — and sometimes, you remember those dreams upon waking.

Sleep and physical activity: a virtuous circle for your health!

There’s a strong link between exercise and sleep quality.

People who are too sedentary face higher risks of cardiovascular disease, diabetes, cancer, and mental health disorders. In the short term, spending too long sitting or lying down without sleeping reduces alertness and causes headaches, muscle, and joint pain. Over time, sleep quality deteriorates, sometimes leading to insomnia.

Regular exercise improves sleep hygiene: you fall asleep faster, sleep deeper, longer, and more restfully. Your circadian rhythm stabilizes, and your internal clock works better. Even moderate physical activity increases the production of endorphins — the “feel-good” hormones that reduce stress and anxiety, helping you relax. But be careful: overtraining or exercising too intensely can have the opposite effect and cause insomnia.

If sport benefits sleep, the reverse is also true. A poor night’s sleep directly affects physical and cognitive abilities. Conversely, studies suggest that athletes can significantly improve performance by sleeping longer and better. Elite athletes need around 8 hours of sleep per night, but many get less than 7. Léon Marchand revealed he had slept 11 hours the night before winning his gold medal in the 200m medley. Usain Bolt also said that one of his secrets to speed was sleeping 10 hours a night.

Let’s bring back the nap!

With our busy schedules, getting a full night’s rest isn’t always possible. Yet, napping is an underrated toolto make up for sleep debt and recover quickly and effectively. Naps improve both cognitive and physical performance and help recovery from muscle damage or inflammation. A good nap lasts between 20 and 90 minutes, ideally between 1 p.m. and 4 p.m.