Sleep is an essential component for good health and well-being. The National Sleep Foundation suggest that adults need around 7 to 9 hours sleep per night. Teenagers and active individuals (such as athletes) require a little bit more, around 8 to 10 hours.
Stages of Sleep
There are four stages of sleep that can be divided into REM (rapid eye movement) and the three stages of non-REM sleep.
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Stage 1 - This stage is considered the lightest as it’s fairly easy to be disrupted and awoken during this stage. As you close your eyes and prepare to drift off, your body will start to relax and your brain wave activity will slow. This stage normally doesn’t last very long (e.g. as little as 7 minutes) as you transition from being awake to sleep.
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Stage 2 - Your heart rate slows and your body temperature will drop slightly in preparation for the next stage - deep sleep. It is more difficult to be woken from this stage. Your brain waves continue to slow but there are spikes of activity known as sleep spindles and K complexes.
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Stage 3 - During this deep sleep stage, your brain activity reduces, breathing slows and muscles relax. The release of the human growth hormone during this phase is believed to play an important role in the revitalisation of the body as it repairs and rebuilds. It is believed to be the most restorative sleep stage, and it's difficult for a person to be awaken during this stage.
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REM Sleep - During this stage your eyes move in all directions and it is when dreaming typically occurs. Your brain activity is similar to when you are awake, your heart rate increases, but the body is inactive (in contrast to stage 3). This stage is believed to be important in the revitalisation of the mind.
Sportspeople go to great lengths to improve their performance, spending considerable time, effort, and money on a number of technical, physical, and psychological strategies. However, strategies aimed at improving something as basic as sleep is often overlooked.
As a junior golf academy coach, I often scratched my head watching students practise hard throughout the day (some up to 6 hours), but then consistently chose to stay up late. All that effort and endeavour to improve, but the benefit of getting a good nights sleep was ignored.
Sleep is arguably one of the most underrated performance factors in sport, and as such its importance is often neglected. A review of 37 sleep conducted by Gupta, Morgan, and Gilchrist (2017) found the majority of athletes fall well short of the recommended daily amount and quality of sleep.
The lack of adequate sleep could be due to a blase attitude of its importance, but to be fair to athletes, sport participation does come with its own problems. For example, athletes:
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may be required to be compete very early in the day (e.g. the first tee-off time in the British Open in 2019 was 06.35am local time) or very late in the day (e.g. in round 3 of the 2019 ATP Washington Open Andy Murray started a match just before midnight and it didn't finish until 3am local time), which will interrupt normal sleeping patterns.
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can become fatigued from the intensity of training and competing, which can effect sleep.
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are often required to travel away from home throughout the season. Travelling can be stressful and sleeping in foreign environments can be problematic.
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may experience stress, excitement, and/or anxiety leading up to a competition, which can be a barrier to a good nights sleep.
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may have to travel across different time zones, where the jet lag and adjustment to a different time zone is needed.
These challenges highlight the need for athletes to manage their sleep. Especially when you consider the that sleep has been found to influence important performance factors such as reaction time, accuracy, memory, fatigue, and the likelihood of illness or injury can all be affected by sleep.
Many sporting organisations have taken note, with some of the world's leading sport teams adding sleep experts to their coaching staff. Teams from the Premier League, NBA, British Cycling, and Super Rugby have employed sleep experts to improve the sleeping habits of their athletes.
Top athletes such as Roger Federer, Michelle Wie, and LeBron James are known to sleep around 12 hours per day (which includes daily naps). This is not just before a competition, but for every day.
It has been suggested that sleep deprivation is one of the primary reasons for human error, and has even been associated with catastrophic events such as Chernobyl and the Challenger explosion. Thankfully in the world of sport, errors from sleep deprivation will not lead to such catastrophic events but it may be the difference between winning and losing. When athletes realise how important sleep is, I have little doubt that they will then pay more attention to it, and add sleep management to their training programme.
IMPORTANT TERMS
Sleep Quality
Sleep quality generally refers to how well you slept. Characteristics of good sleep quality include:
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Sleeping for at least 85% of the total time you are in bed
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Waking up no more than once during the night
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Being awake for less than 20 minutes or less after you have fallen asleep
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Proper staging of sleep (i.e. cycling through non-REM and REM sleep)
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Wake up feeling rested
In contrast, poor quality sleep would be characterised by trouble falling asleep, sleep interruptions, restlessness, and waking up early.
Sleep Debt
Sleep debt refers to a deficit in sleep, in regards to a single nights sleep and/or from multiple nights. For example, if your optimal sleep is 8 hours per night, and you have only slept 6 hours on each of the previous two nights, you would have a sleep debt of 4 hours over the previous 48 hours.
Sleep Deprivation
Sleep deprivation is when sleep is restricted or limited to less than six hours per night. Total Sleep Deprivation generally refers to being awake for a period of 24 hours or greater.
Sleep Cycle
Throughout the night you will cycle between the different stages. You will progress through the non-REM stages of 1, 2 and 3. Then after stage 3, stage 2 is repeated and you move on to the REM stage of sleep. A person will typically cycle through these stages 4 to 5 times a night, but the time spent in each stage will vary.
Sleep Duration
Sleep duration essentially refers to the total amount of sleep obtained over a specific period of time. For example, if a person slept from 10pm to 7am, their sleep duration would be 9 hours within that 24 hour period (assuming no additional sleep or naps were taken).