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Importance of sleep affecting sports performance

Recently I uploaded a review of the Withings Aura. Why? might be a good question. Yes it’s a gadget and its vaguely related to health. But let’s be honest, as a review item, it was a little out of left field. The main reason being that sleep is important. I don’t just mean its nice. I mean bone healing, bike riding, muscle building, racing winning important. Sleep affecting sports performance is part of your training you might not have looked at…
In the modern world, we are VERY busy. We want to do more, be more productive, see more, have more. To quote from the H. Thoreau and the Dead Poets society, we want to “…Live deep and suck the marrow out of life…”

The problem with that, a little bit like burning the candle at both ends, is we run out at some point. How many people have your heard say they feel there are not enough hours in the day, or just feel they are spread too thinly?

Today we are sleeping less, on average, than our parents generation. The average American, sleeps 6.8 hours a night, rather than the 7.8 in the 1940’s, and this is mirrored across the Western World.

Two things are leading this tread. 1) the need to DO more, which is itself interesting, given that productivity in the UK is currently 30% less per hour than in other areas of Europe, but also 2) the environment we live in, which is now more of a genuine 24hr society than ever, especially with the internet.

Blue Light

As for doing more, I don’t think that is an easily modifiable factor, if changeable at all. However our environment, our use of LCD/TFT screen late at night, or in the bedroom is a big, and easily chanagble factor.

The normal white colour seen as the background to most of our electronic devices is actually contains a lot of blue light. Its one of the reasons why the screens sometimes look cold. A good example here is the older incandescent bulbs which give a warm yellow light, compared to the whiter, but colder and bluer light of energy saving bulbs.

The blue light from these bulbs and devices mimic the light coming from the sun, and stops the production of our sleep hormone, melatonin. For that reason its advised not to be using electronic devices within a hour of going to bed and certainly not in bed. Personally I can attest to this, if I do switch off an hour or so before going to bed, I fall asleep without issue. However if I’m checking emails etc in bed – daft I know – then I tend to be awake much longer, simply because my brain is wired to be awake with bright light.

Importance of sleep affecting sports performance

Banning devices from the bedroom is a great way to start if you have sleep problems

Does it matter though?

But before any change, is made. Why bother? Sure I wake up a little less rested some days, but otherwise, I’m fine – or so I think.

Be that is as may, it’s likely that some areas of my life could be better than just fine. Part of this is undoubted be related to sleep I manage to get.

One of the areas we are now seeing sleep being recognised as a powerful intervention is in the world of sports, particularly the effect of sleep on sports performance which is seen through several effects:

  • Mental energy
  • Restoration of muscle energy stores
  • Repair of muscle from training
  • Repair of injury – which from my perspective is something I was very interested in

That mental energy boost will be seen in day to day life, not just when in the saddle.

In addition to activities, sleeping is vital to recovery and that also means healing. Very early in my recovery from a fractured olecranon, I was advised to sleep long and sleep well, as this is when the body will be doing a lot of its repair functions, and rebuilding, especially the lay down of new bone. I do think having the time off work – as a doctor you can’t really work with just one hand – to recovery and recuperate really had a massive impact on my healing.

Mental energy

This is slightly harder to discuss, but we’ve all felt that fatigue. The “I can’t get out of bed”, or more annoying the “I’ve just got empty legs” when you have managed to push yourself out of bed for that early morning training session. This is something that can be seen easily in power meter readings. A tired cyclist, just won’t be able to spin the pedals at the same wattage when they are tired, as when they are rested and refreshed.
Ways to affecting positive change in your sleep health
  • Avoiding distractions around bed time
  • Trying to use warm lighting as you go to bed – personally I’m using Philips Hue bulbs that are set to dim in the bedroom across the evening, and at night if I do need to get up, they switch on to a red, submarine-esq glow, to try and maintain my sleepy demeanour.
  • Avoid using technology in bed and unnatural white lights – if possible leaving phones in a different room or switch of – personally thats going to be a hard one
  • Have a set routine and follow it – it takes about 3 months for the body to adapt to a new routine, so setting a bed time and rise time and sticking to it is going to real help
  • Try to even out sleep over the week rather than building up a sleep debt during the week and trying to sleep it off at the weekends. This is particularly important, as “sleep maths” doesn’t work like this. Even if you over sleep by 2-3 hours at the weekend, each night you are only able to pay back 1-2 hours of sleep debt, even if you sleep for longer than that.

Sleep cycles

Understanding sleep cycles is the key to a good nights sleep, effective waking, and maximising your sleep and thus performance. The phrase maximising your sleep might sound daft, but even though your brain is consciously switched off, your body is still very active. Rather like the changing shifts in an office block, just because the day workers are not there, doesn’t mean there isn’t plenty going on with regard to maintenance of the building

The first thing to learn about the sleep is it is not merely a singular block of sleep, but is actually an active process consisting of two phases, and sub divided into stages:

There are two main types of sleep:

  1. Non-Rapid Eye Movement (NREM) Sleep
  2. Rapid Eye Movement (REM) Sleep

Within NREM sleep that are three sub stages 1-3 which you need to pass through to get to the restorative REM sleep.

Moving away from the 8 hours of sleep concept, we now appreciate the the optimum level of sleep is between 5-6 sleep cycles. The average duration of a sleep cycle is about 90mins, which interesting puts us back towards the 7.5hrs of sleep. But its not just the duration of sleep, different processes are going on between each sleep stages, which is why unbroken sleep is the key.

Sleep Stages

Importance of sleep affecting sports performance

Sleep cycles become shallower with duration, hence easier to wake in the morning

Stage 1

The first and lightest stage of sleep, when you are actually moving between wakefulness and sleep, hence could be considered an active stage as sleep. This is the easiest part of sleep for simple activity trackers to monitor, and is how Garmin determines when you are awake asleep. Stage 1 is a relatively brief period lasting 5-10minutes, and is likely for the reason the phrase “dropping off” exists, as you can be roused from Stage 1 very easily. This is where sleep monitoring comes in with regard to alarms, as the alarm will try and trigger when it detects an increased movement from the sleeper, indicating a movement into the lighter stages of sleep.

Stage 2

The second stage of sleep lasts for approximately 20 minutes, and is more of a transition phase. Here the body prepares for sleep, slowing activity, lowering heart rate and decreasing body temperature

Stage 3

Here the brain activity slows, you become much more difficult to rouse as you pass into the deeper stages of sleep. If you are woken during this stage of sleep, you are normally disoriented and groggy initially.

REM Sleep

Rapid eye movement sleep is where dreaming occurs. This is the restorative part of sleep, with dreams postulated to work a little like defragmenting a hard drive. Whilst the brain is becoming more active at this time the muscles become completely relaxed, helping the process of healing and muscular recovery.

You cannot cheat sleep. If you are not sleeping enough there is no way to compensate for this. Even if you are not getting the ideal about of sleep, you can still to and modulate when you go to sleep, with regard to the 90min cycles of sleep to try and avoid waking up in Stage 3, in the middle of deep sleep – which I’ll discuss a little further down

Knowing your sleep

There are now many products out there able to monitor your sleep and give you a good idea of what your sleep performance is like. Withings Aura is an expensive way of doing that, but it looks at a much more active way of helping you sleep. The Sleep Cycle app similarly looks to monitor you sleep to help you wake less groggily with your alarm. Plus most of the Garmin devices containing activity trackers have recently been updated via firmware with rudimentary sleep tracking based upon your movements in bed.

Importance of sleep affecting sports performance

Garmin rudimentary sleep tracking

Sleep planning

By knowing that sleep occurs in 90 minute cycle lengths you can plan when you need to be going to sleep, in order to avoid your alarm going off when you are in the middle of deep sleep.

If for example you need to get up at 7:30am, and assuming you fall straight to sleep, you would need to be asleep by 10:30pm in order to get 6 full cycles of sleep, but also to be naturally passing into lighter stages of sleep as your alarm goes off at 7;30 am, hopefully resulting in you waking fresh, not groggy.

We now appreciate that sleep has a much greater impact on exercise than just not being active. Based on that, an actively training athlete, who is sleeping for <6hrs a night can considered to be severely sleep deprived

Most athletes tend to be able to fall to sleep easily, but anyone who is awake for >15mins when trying to get to sleep tends to suggest an issue with their sleep hygiene. This is most frequently related to the sleep environment, using artificial lights and screens within the hour before going to bed, and impacting on melatonin, the sleep inducing hormone. As a result some people use medications, and supplements to help them get to sleep. Whilst this does knock you out, it is likely that the effect on the sleep quality is going to be significant.

Zopiclone, an often prescribed sleep aid, from the group of medications referred to as hypnotics, does help a person to sleep, but it also halves the quality of the sleep. Meaning that if a person is managing 6 hours a night with Zopiclone, the effect could be that they are only getting the equivalent of 3 hours of restorative sleep.

It is thought up to 23% of athletes use some form of medication to encourage sleep, but this might actually be causing them more harm than good. Sleep is quite literally an example of quality being as important as quantity. As a result I now personally try to avoid sleep medication if at all possible, and when prescribing it, highlight it should only be used for the shortest time possible.

The Importance of sleep affecting sports performance

Its very nice to know that carefully monitoring sleep is likely to help you wake more easily. But does it really have any effect on exercises or sports? Crucially if I sleep more, is it going to help me get that triple jersey on Zwift?

Based on that question, I found the following paper Mah et al. (2011), where they investigated the effect of sleep on athletes sprinting times. They were timed before the start of the experiment sprinting nearly 100m, before being encouraged to sleep as much as possible over following 5-7 weeks, whilst not increasing their training and keeping nutrition the same. Their sprints were then were re-timed over 100m after the sleep period. Their results showed on average approximately a 1 second reduction in sprint times compared to previous times.

Whilst this on its own might not appear to be a massive time saving, it should be noted the the short distance of the sprint. In addition, the paper also reported measurable improvements in reaction time, daytime sleepiness, and mood after the sleep extension period.

Based on this initial finding finding, the same research group applied the same approach to looking at sleep duration on a group of swimmers. Here the subjects where asked to target  10 hours of sleep per night for over 6-7 weeks. After the study, the swimmers again showed distinct improvements over 15 meter sprint distance, reaction time, turn time and mood.

Based upon research such as this, Team Sky and various Cycling teams support their riders in getting sufficient sleep, but also encourage the use of naps throughout the day in order to help reach these sleep goals, and the maximise recovery from training, given the muscle relaxing effect of REM sleep.

Conclusion

Lastella et al 2015 also showed that most athletes dont achieve the advised 8 hours of sleep a night. This is thought to be based upon other factors around the sport, such a family, social and work commitments. However the evidence does suggest, if you have a competitive event that you are training hard for, it might also be worth while making sure that your sleep is not being neglected as part of your training.

If not training then looking at your sleep patterns is at least going to enable you to climb out of bed with more ease, than if you alarm hits you randomly in REM sleep!

Plus if you are recovering from injury, sleep is another crucial part of your rehabilitation, that should take minimal effort to maximise

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