Exercise and sleep quality – what matters?

Sleep plays a vital role in our daily lives. It is whilst we rest that our bodies regenerate, rebuild cells, strengthen the immune system and enable us to function at full capacity. However, we are increasingly struggling with sleep problems – insomnia, waking up frequently during the night or feeling tired despite spending a long time in bed. Among the many methods for improving sleep quality, one of the most effective is regular physical activity. But exactly how does exercise affect our sleep? Is simply getting active enough to help us sleep better?

1. The effects of exercise on our bodies
2. Types of exercise and sleep quality
3. Exercise and the regulation of the circadian rhythm
4. Exercise and stress and anxiety
5. Exercise and deep sleep
6. Relaxation exercises and yoga

The effects of exercise on our bodies

Physical activity isn’t just a way to lose weight or improve fitness. It’s also a powerful tool for supporting mental and physical health. During exercise, the body produces endorphins, which act as natural painkillers and boost your mood. In addition, exercise helps regulate cortisol levels – the stress hormone, an excess of which can disrupt the sleep cycle. Regular exercise also improves cardiovascular function, increases stamina and helps maintain a healthy weight.

But that’s not all. During physical activity, body temperature rises, and after it ends, it gradually drops. It is precisely this drop in body temperature that signals to our nervous system that it is time for sleep. That is why exercise, especially when done during the day, can help us fall asleep faster and sleep more deeply.

Types of exercise and sleep quality

Not all forms of exercise have the same effect on sleep. Much depends on the type, intensity and timing of the activity. For example, moderate aerobic activity, such as a brisk walk, cycling or swimming, offers significant benefits. On the other hand, intense strength training or cardio sessions carried out just before bedtime can have the opposite effect and make it difficult to fall asleep.

"Unfortunately, sleep is ignored by most people who train as a factor influencing training results. Perhaps for a man aged 20–25 it isn’t that important yet, but with every passing year hormonal conditions change and rest begins to be a priority!" – Tomasz Maciołek – Physiotherapist and Trainer

The best time to exercise is in the morning or early afternoon. This gives the body time to cool down and prepare for rest. However, many people prefer (or only have the option of) afternoon and evening workouts. And this doesn’t have to be a problem, provided you ensure that your workout takes place around two hours before your planned bedtime. Otherwise, elevated levels of adrenaline and endorphins may make it difficult to fall asleep and reduce the quality of your sleep.

Exercise and the regulation of the circadian rhythm

Our bodies function according to circadian rhythms, or a biological clock, which regulates, amongst other things, sleep and wake cycles. Regular physical activity helps to synchronise this clock, which translates into better sleep quality. People who exercise regularly are less likely to have trouble falling asleep or waking up during the night, and feel more refreshed upon waking.

Interestingly, even short workouts, lasting around 10–15 minutes, can have a beneficial effect on our circadian rhythm. For example, a brisk walk in the fresh air after work or morning yoga can work wonders for our sleep rhythm.

Exercise and stress and anxiety

Stress and anxiety are among the main causes of sleep problems. High levels of stress trigger the release of hormones such as cortisol, which make it harder to fall asleep and exacerbate problems with deep sleep. Regular physical activity acts as a natural way to reduce stress levels. During exercise, endorphins are released, which improve mood and help you relax.

Furthermore, exercise can improve sleep quality by reducing symptoms of anxiety and depression. People who exercise regularly are less likely to experience psychological insomnia. Therefore, if you’re having trouble sleeping due to stress, it’s worth incorporating even a short session of relaxation exercises or yoga into your day.

Exercise and deep sleep

Deep sleep (the NREM – Non-Rapid Eye Movement – phase) is crucial for the body’s full recovery. It is during this phase that tissue repair, immune system strengthening and memory consolidation take place. Regular exercise, particularly moderate-intensity exercise, helps to extend the time spent in the deep sleep phase.

Scientific research confirms that physically active people tend to sleep more deeply and effectively. As a result, they feel rested and full of energy in the morning. Importantly, this does not necessarily mean long training sessions – even 30 minutes of moderate activity three times a week can bring noticeable benefits.

"Sleep is also linked to the rhythm of testosterone secretion, which plays a role in maintaining muscle strength and mass. If sleep is too short or interrupted, these processes become less effective and the body does not fully utilise the potential of training." Łukasz Domeracki – Nutritionist and Personal Trainer

Relaxation exercises and yoga

In addition to traditional forms of exercise, relaxation exercises and yoga are becoming increasingly popular. Their main aim is not only to improve flexibility and strength, but also to calm the mind and prepare the body for sleep. Yoga, particularly its gentler forms such as Hatha or Yin, helps to reduce tension, lower cortisol levels and calm the nervous system.

In summary, regular physical exercise has a number of beneficial effects on the quality of our sleep. It helps us fall asleep faster, sleep more deeply and wake up less often during the night. It aids in regulating the circadian rhythm, reduces stress and anxiety levels, and promotes deep sleep phases. The key is to choose the right type and time of exercise so that it does not disrupt the rest process. It is therefore worth incorporating physical activity into your daily routine, as it is an investment in your health, well-being and – most importantly – the quality of your sleep. Remember that sleep and exercise are the two pillars of a healthy life, which should be treated as inseparable elements of everyday life.

Sources:

• https://pmc.ncbi.nlm.nih.gov/articles/PMC10503965/ 
• https://www.nature.com/articles/s44323-024-00018-w