12 Apr The Importance of Sleep
Whether you are an elite athlete, weekend warrior or someone who does almost no exercise (naughty!) – a good night’s sleep should be held as a high priority for maintaining quality performance and/or good health.
The following article will briefly discuss the physiology and benefits of sleep, as well as list some effective strategies for falling into a deep slumber.
The physiology of sleep
There are two types of sleep:
- Non-rapid eye movement (NREM)
- Rapid eye movement (REM)
NREM sleep begins as light sleep and gradually deepens. Each sleep cycle is closed out with a period of REM sleep, where activity is high, and dreaming is said to occur. Each cycle lasts about 90 minutes.
The optimal amount of sleep for an adult is a source of debate. The old rule of thumb has been eight hours per night, however another common theory suggests that quantifying sleep by its number of cycles, with the aim being to wake up at the end of a cycle (where you should be able to awaken with less fatigue and disorientation), is more appropriate. Under this guideline, it is recommended to set your alarm to wake up at the end of a sleep cycle. For example, if you go to bed at 10.00pm, setting your alarm to 5.30am or 7.00am the following morning should mean that, with an uninterrupted sleep, you wake up at the end of your fifth or sixth cycle, thus feeling fresher for the day ahead.
While this sounds good in theory, the reality is that sleeping throughout the night without awakening is not always the case for many people. Therefore, I generally recommend to my clients and athletes that they aim for eight hours of sleep per night, which accommodates for some of the research that will be discussed below.
Why is sleep so important?
Sleep is important for regulating the central nervous system and cognitive function. Sleep also affects the immune system – for example, those who sleep less than five hours are 4.5 times more likely to have a cold than those who sleep for seven hours per night (Prather et al., 2015).
For athletes, sleep is the time where the concentration of growth hormone (which contributes to muscle growth and repair) in the body is at its highest. Furthermore, a lack of sleep can affect strength and power, energy stores, and increase the risk of injury (Milewski et al., 2014).
Tips for improving sleep
- Avoid stimulants, such as coffee, after lunch. Caffeine has a half-life of around six hours, so an afternoon hit can certain carry over into your regular sleep schedule if not spaced properly.
- Avoid drinking too many fluids in the hours before bed, to avoid waking up with the need to urinate.
- Set a relaxing routine in the hours before bed. Whether this is reading a book or having a hot bath, activities that allow you to wind down and relax will encourage your body to sleep.
- Avoid using electronic devices 60-90 minutes before going to bed. The blue light can suppress sleep hormones, making it harder to fall asleep when you try to. If using your mobile phone or a tablet close to your bed time is an absolute necessity, some devices have a ‘blue light filter’, or you can download an app. It is prudent to note that the effectiveness of these filters is still unclear, so the best strategy is to avoid these devices altogether.
- Try and maintain a consistent set of times that you go to bed and wake up (yes, especially on weekends). Avoid sleeping in.
- Make sure your bedroom is as dark as possible.
- Keep your bedroom at a cool temperature (think of how difficult it is to sleep without an air conditioning on a 25-degree evening).
- If you are struggling to fall asleep, try a breathing strategy called ‘parasympathetic breathing’, which is aimed at restoring your body to a state of calm. Lying on your back and relaxing your muscles, take a deep breath in, hold, and breathe out, all for several seconds each, repeating this process several times. Another option is to download one of the many mindfulness apps to listen to. These apps draw your attention back to the present moment and to focusing on your senses, and may give you that little extra sense of calm you need to peacefully drift off to sleep.
- If you have had a poor sleep overnight, a 20-minute nap during the day can assist with restoring physical and cognitive function, as well as alleviate stress. Try not to nap too late in the afternoon, as napping close to the time you would normally go to bed may impact your sleep for that night.
Milewski et al., (2014). Chronic lack of sleep is associated with increased sports injuries in adolescent athletes. Journal of Pediatric Orthopaedics. (34).2.
Prather et al., (2015). Behaviourally assessed sleep and susceptibility to the common cold. Sleep (38).9.