How does sleep affect your performance?

Sleep. It’s something we all do, it’s something we all need. For most of us, it’s something we need to do more! But why exactly do we need to spend so much of our time in the land of nod; and in what ways does a lack of sleep affect our exercise and athletic performance?


There are 3 basic stages of sleep/wake cycle, which are linked to what is known as your circadian rhythm. Your circadian rhythm refers to the changes which occur to some of the chemicals in your body, and your body temperature, over a 24 hour period. This is usually regulated by times of light and dark.

The 3 basic stages of the sleep/wake cycle (two occurring during sleep) are:

  • Awake
  • Non Rapid Eye Movement (Non-REM) sleep
  • Rapid Eye Movement (REM) sleep

Non-REM sleep can then be divided into 4 more sub-stages of sleep, where the depth of sleep gradually increases.

Over the course of the night, the body cycles through the different stages of sleep. Non-REM sleep usually takes up about 80% of your time in bed, while the remaining 20% is REM sleep. Typically, REM sleep occurs throughout the night, at intervals roughly 90 minutes apart.

When you go to bed, your body gradually works through the 4 stages of Non-REM sleep. Stage 1 is fairly light sleep, with stage 2 being slightly deeper; but people can be easily awoken during each of these stages. Stage 3 and 4 are deeper still, and are often referred to as “slow wave” or “delta” sleep. Breathing and heart rate both gradually decrease over the course of the 4 stages, as does muscle tone.

REM sleep is quite different. This is where dreams occur; and the body experiences irregular, rapid changes in both heart rate and breathing. Muscle tone during REM sleep is very low….it is thought this may be to stop people moving their limbs and injuring themselves (or others) while they are dreaming!


Although the role of sleep is not fully understood, the 2 basic stages of sleep seem to serve different purposes.

Non-REM sleep is believed to help restore the body. During deep, slow wave sleep, there is a fall in metabolic rate, and temperature. But there is also an increase in growth hormone and protein synthesis during deep sleep; which is why we believe Slow Wave Sleep is important for muscle growth and tissue repair. Obviously, this is an important part of recovery for an athlete!

REM sleep is thought to help with memory; sorting through short term memory stores, getting rid of useless information and establishing a basis for long term memory.


So, does sleep actually affect our performance while out exercising, or playing sport? Well….the answer is a little bit complicated. Sleep disturbance is known to affect cognitive functioning, but it may not actually reduce physical function. Conflicting evidence in research shows that performance can be affected by disturbed sleep, but the explanation as to why remains unclear.

Studies into athletic performance and sleep deprivation show that endurance performance is often affected by periods of inadequate sleep; while the effects on anaerobic power are less clear. Glycogen muscle stores have been shown to decrease as a result of poor sleep, which may have an effect on endurance type sports.

However, data also suggests that the changes in athletic performance may not be due to a reduction in physical function, but rather an increase in the Rate of Perceived Exertion (RPE)….especially for shorter, anaerobic efforts of exercise.

We do know that for skill based sports, the reduction in cognitive functioning definitely has an effect on performance. Essential skills such as hand/eye co-ordination, quick decision making, accuracy and fast reaction times are reduced as a result of poor sleep. Obviously, this can have a negative impact on your abilities when training and playing sport. Reduced cognitive function can also lead to an increased rate of injury, due to a simple lack of concentration and awareness….obviously, this can happen during all types of sport and exercise!

Poor sleep can also have a negative effect on mental health, which can, in turn, have some negative results on exercise and sports performance.


There are many reasons why people have trouble sleeping. Stress, anxiety and boredom, as well as things like diet, alcohol and caffeine intake, amongst other things, can all negatively affect your sleep. But there are many strategies which may help to improve your sleep patterns.

Sedatives, both prescription and non-prescription are often used as a sleep aid. But they are not the best option. While they may help you get a full night of sleep, many people end up being quite drowsy the following day; due to the fact that these types of tablets basically knock you out and affect your sleep pattern. You may sleep, but it probably won’t be restful, restorative sleep.

Melatonin, which is usually produced by your body as part of the sleep cycle, can be of benefit to some people. Being a prescription medication, this is something you will need to talk to your doctor about though.

Natural, herbal remedies such as chamomile and valerian are a preferred option by many. However, research shows that there is little evidence to support the fact that these alternatives actually assist with sleep.

The best option for a good night sleep is to incorporate a healthy, regular routine which promotes a good sleep/wake cycle:

  • Get up at the same time each morning, and go to bed at the same time each night
  • Utilise morning light to help you wake up properly
  • Eat meals at around the same time each day
  • Exercise daily, ideally at the same time each day….but not immediately before trying to go to bed
  • Find time to unwind for at least an hour before bed
  • Dim the lights and ditch the devices before bed
  • Only attempt to go to bed when you are actually sleepy

Utilising these strategies, as well as keeping your mind active during the day and socialising with friends and family on a regular basis, can assist in getting a good night sleep; and letting your body perform at it’s best!

Of course, if you have ongoing sleep issues, it’s always worth speaking to your health care professional, to ensure there is no underlying medical reason for your problems getting a good night of rest.

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