How Sleep Can Affect Athletic Performance

Professional athletes follow a strenuous routine that pushes their body to the absolute limit, and for this reason, this makes sleep an incredibly important part of their life. 

Sleep is just as crucial for survival as air, water and food, while also being vital for athletic recovery and development. The sleep your body demands will vary from person to person depending on behavioural, psychological, social and environmental factors, but for athletes, this will vary further according to their personal physical and psychological attributes.

This has led to considerable interest in the relationship between sleep and athletic performance. An athlete’s day is scheduled out by the minute including diet, travel and training; however, rest is less often addressed by coaches despite them knowing how key it is for athletes.

This is mainly because there is a lack of extensive studies because most of them are based on a low number of participants with minimal standardisation. We’ve collated all this data to show you how important sleep is for achieving optimal athletic performance.

Sleep and its Effect On Athletic Performance

Sleep is crucial for athletes because the quality and duration achieved impacts multiple athletic attributes that they rely on for performance including, speed, reaction times, concentration, recovery.

The body repairs itself throughout sleep, so it’s vital for recovery post training. When your body's well rested, this means that you won’t need to use extra energy to focus and stay away which means you can give your full focus towards your athletic performance.

Reaction times

Milliseconds at an elite level is often the difference between winning and losing. Sleep deprivation can have a significant effect on reaction times with one study exploring its consequences. One study in 2000 with Williamson A, Feyer A. as a researcher set out to discover the relative impact on the performance of sleep deprivation and alcohol.

The study involved 39 subjects and was over 28 hours of sleep deprivation. The results showed that after 17-19 hours with no sleep, performance on reaction time tests was worse than having a blood alcohol level of 0.05%. Some response times were as high as 50% slower on some assessments.

This shows how important sleep is especially if you’re in a sport where reaction times have a significant bearing on the overall result such as Sprinting.
Recovery Time & Longer Playing Careers

Long term sleep deprivation can also play a significant role in the longevity of their peak athletic career. This was highlighted in a study which found a relationship between the sleepiness of 80 MLB players and the overall length of service they gave to the league. 

As players gave higher baseline self-reported scores of sleepiness on the Epworth Sleepiness Scale, the chances that the player would still be active in the league three seasons later, decreased proportionally.

It shows that sleep deprivation can not only have a short-term impact of causing athletic decline but also long term if you continually fail to get adequate sleep.

For example, 72% of surveyed players reported a baseline Epworth Sleepiness Scale score of 5 was still in the league three seasons later, compared to just 39% of players who reported a score of 10.

Injury Prevention 

Hugely linked to having longevity in your athletic career is your ability to avoid injuries and stay healthy, so it’s no surprise that there’s a link between sleep and injury prevention.


The way this works is a lack of sleep results in higher fatigue levels and less joint/muscle recovery. This tiredness can affect your decision making and reaction time which can make you less safe from avoiding injury and dangerous situations such as evading tacklers Rugby.

Fatigue can also affect a person’s immune system making you more prone to contracting illness which leads to more time out of your sport.
A study  at the University of California studied this relationship by surveying 112 adolescents on their sleep habits and injury records.

The analysis of these results revealed that the athletes who slept for less than eight hours per night were 1.7 times more likely to experience injury compared to athletes who got more than eight hours per night.

Another study took place which analysed injury rates of 360 pupils at a high school and discovered that the number of hours was the most significant predictor of getting injured. Pupils who slept for under 6 hours were more likely to get injured compared to those who slept for more than 7 hours per night.

Greater Mental Concentration

Lack of sleep doesn’t just affect you physically but also psychologically which can lead to worse decision making. Studies have revealed that focus and memory can also be altered with lower levels of sleep. It's due to the brain struggling to process new information and stimuli which then takes you longer to make a decision.

This was investigated in a study of 30 MLB players which showed that a players plate discipline got worse as the season progressed. Plate decision is characterised as the frequency that a player swings at a ball that is outside of the strike zone.

Ordinarily, you would expect plate discipline to improve throughout the season as the player bats more often. However, the opposite occurred which can be partly attributed to mental fatigue and concentration. With greater fatigue management this is one-way teams can gain a competitive edge.

Less sleep = lower energy levels

As you’d expect, as an athlete the less sleep you get at night, the less your energy levels will replenish. Throughout sleep, Melatonin is secreted which triggers the activation of other enzymes which help to reduce inflammation, repair muscle and joints.

If your body is deprived of sleep, this can slow down the creation of vital energy sources such as carbohydrates and Glycogen which are the primary energy source during high-intensity activity. If these reserves are exhausted, then you will have less energy to use, so this can lead to worse performance.

So it’s common sense that unless you want to rely on energy supplements, then you need to ensure that you’re getting enough hours of sleep every night.
How does directly affects performance?

There are many investigations into the actual athletic performance improvement once sleep has been managed effectively which prove that it’s worthwhile to take your sleep more seriously.

Stanford University’s Center for Sleep Sciences and Medicine has been at the forefront of examining the relationship between sleep and performance, and researchers have executed many studies featuring students across a range of sports with a sample of the results displayed below:


A study took place with five members of the women’s and men’s swimming team at Stanford which involved increasing their sleep to 10 hours per night. This resulted in improvements for a range of stats including reaction time (-0.10 seconds), turn time (-0.10 seconds), speed (-0.51 seconds) and the number of kick strokes (5 kicks).

Similar to the Swimming study, five tennis players on the University of Stanford tennis women’s team were instructed to increase their nightly sleep to 10 hours for a duration of five to six weeks.

The extended rest was reflected in there performance with there recorded sprint times dropping on average from 19.12 seconds to 17.56 seconds which represents an 8% fall. Also, the number of valid serves delivered increased from 12.6 to 15.61 (24% rise).

A study featuring 11 members of the Stanford University basketball team prolonged their nightly sleep to 10 hours. After five to seven weeks of this, the players were tested, and the results from in-game statistics showed that shooting accuracy improved with three-point shooting improving by 9.2% and free throw percentage success increasing by 9%.


American football:
Seven players on the Stanford football team slept for 10 hours over 7-8 weeks, and the results followed a similar trend to the other sports studied by the university.

Their times in the 20-yard shuttle and the 40 yards dashed both decreased by an average of 0.1 seconds. Results weren’t just physiological as players also reported improvements in their overall mood and wellbeing.

Sleep doesn’t just improve performance when you get 10+ hours, but if you get too little, then this can have the opposite effect which can lead to a decline in athletic output.

Unsurprisingly, lack of sleep will also decrease ability within athletes below their perceived baseline levels both short term and long term. One study involved eight male subjects aged 18-24 who were then limited to 3 hours of sleep for three nights in a row.

They then took part in weightlifting tests which showed a significant decrease in performance in comparison to their previous baseline levels obtained on the first day of the study.

In an alternative study, and investigation to place into the effects of sleep deprivation on essential football skills including dribbling, ball control and sprints or pre-determined distances. Nineteen junior football players took part with one part of the testing taking place to fit in with their natural sleeping hour, and the other half after 24 hours of no sleep.

The results revealed that when sleep deprived the players had to repeat the exercise more times until they executed it correctly and there was an adverse effect on sleep deprivation and continuous kicking test. This shows that sleep deprivation can affect you both physically and psychologically.

Sleep and HGH

Human Growth Hormone is a vital hormone which works to repair and restore the cells and tissues within your body. It is estimated that up to 75% of growth hormone is released throughout sleep.

What’s more important is that higher levels of the hormone are released during deeper slower wave sleep. This means that if you’re continually getting low quality or disruptive sleep, then this can affect how your body recovers from athletic performance. Too little rest and your body can struggle to repair itself leaving you more prone to fatigue.

This is one of the main reasons that professional athletes often report to sleeping upwards of 10 hours per night because this maximises the releases of human growth hormone.

Sleep and Testosterone

Testosterone is one of the primary sex hormones that are vital for physical development and recovery in both men and women. Testosterone also strengthens muscles, joints and bones while also decreasing body fat to encourage lean body mass.

One study featuring ten healthy men from the University of Chicago campus revealed that after one week of nightly sleep of just 5 hours decreased testosterone levels by 10-15% compared to when they slept for 10 hours per night. The subjects also reported a fall in their mood and well-being as their testosterone levels fell.

Sleep and Overtraining

Does sleep affect overtraining?

The critical physical processes take place during sleep stages and this recovery during the different sleep stages is vital to allow the athlete to perform at their peak ability the following day. Overtraining is an issue that is a result of long-term training fatigue that will limit your athletic output.

Athletes will be able to train longer and more intensely if they then get sufficient sleep to repair their musculoskeletal & endocrine system. The sleep needs will vary from person to person and quality is just as important as the duration. Sleep quality will fall if you continually experience disruptions throughout the night.
Most symptoms of overtraining can largely be avoided if adequate sleep is obtained consistently.

Top 3 sleep tips for athletes

Have a well-suited mattress & pillow

It’s no good if you get the recommended amount of sleep each night but your sleeping on a pillow and mattress that isn’t suited to your requirements.

It’s essential to ensure that both your pillow and mattress match your sleeping style and position, so your body is well supported throughout the night especially your back, neck, shoulders and head.

If you don’t then this can lead to aches and strains developing that will negatively affect your athletic performance and leave you less well rested and with lower energy levels.

Consistent routine

Most people look forward to the weekend because it means that they can relax and sleep in, but all this does is disrupt your natural body clock which you then have to fix just a couple of days later when Monday rolls around.

This is because the delayed wake-up time means you’re exposed to lower levels of daylight which then delays your next sleep. This can lead to physical and psychological fatigue issues.

Consistency also continues into your routine to wind down for bed. If you consistently follow the same pattern of actions, then your body will recognise these triggers and begin to relax. These actions could be as simple as dimming the lights or having a pre-bed snack but, it makes it easier for you to asleep.

Get 8 -10 hours of sleep

If you’re serious about improving your athletic ability, then you need to ensure that you get a minimum of 8-10 hours of sleep per night. As you can see from the Stanford studies that have been cited earlier in the article, getting a few extra hours of sleep per night can make a big difference in your overall ability.

This is even more critical if your sport is high intensity and you frequently play which means that your body needs sleep time to recover and replenish its energy reserves.

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