Sleep and Athletic Performance

Sleep is essential for general health and wellbeing. 

The more we learn, the more we realise that increased sleep duration and quality is associated with better performance in sport and life. The National Sleep Foundation recommends adults get between 7-9 hours of sleep each day for optimal health (1). But it's not clear exactly how much sleep athletes need. It's been suggested athletes require more - closer to 9-10 hours (2). But duration is not the only factor - sleep quality is also important. Getting the right amount of good quality sleep has some incredible benefits for athletic performance. Let's take a deeper look... 

Recovery

Image source: Getty images

Image source: Getty images

For an athlete, sleep is the ultimate form of recovery. It's like a big sponge that soaks up fatigue overnight. This sponge assists with the recovery process so we can adapt from and absorb hard training. The bigger the sponge (sleep duration), the more water (fatigue) it can soak up. 

It's in the deep sleep phases (Stage 3 and 4 NREM) during the first half of the night that we do most of our physical recovery and repair.

The light sleep stages which make up approximately 50% of a total nights sleep (Stage 1 and 2) are also key to both physical and neural recharge overnight. If we don't spend enough time in these phases, we wake up feeling foggy.

Sleep is a WEAPON
— Jason Bourne

Reaction time, coordination and accuracy

It's in Stage 5 (REM) sleep where our brains recovery, learning and development occurs. We create new nerve pathways to consolidate and repair memories, skills and process information. Side note - it's also where we release testosterone (in both men and women). Research suggests that sleep deprivation delays the signals which travel along these pathways, decreasing our coordination and accuracy (2). So much so that inadequate sleep has been likened to being drunk! Williamson and Feyer (2000) demonstrated the longer the duration without sleep (up to 23 hours), performance in cognitive tasks, motor skills, speed and accuracy decreased to levels equivalent to a blood alcohol content of 0.1%. Twice the legal driving limit in Australia!

The duration of REM sleep increases as the night progresses, with the longest duration occurring just before waking. So get to bed early to ensure you get the beneficial effects on mental performance more REM sleep brings.

Injury & illness

Decreased sleep has been associated with an increased risk of injury and illness. Inadequate sleep is immunosuppressive, increasing our risk of upper respiratory tract infections. In a study of 164 adults administered nasal drops containing rhinovirus, those who slept for less than 5hrs were 4.5 times more likely to develop an illness than those that slept for greater than 7hrs (4).

Being sick or injured reduces training availability and is obviously something we want to avoid. The underlying mechanism for increased injury with sleep loss is unclear but is likely due to cognitive impairment and decreased reaction time, along with higher levels of fatigue. All of which can increase an athletes risk of injury.

Mental stamina and mood

Striving to be fitter, faster and stronger doesn’t just require physical effort, it also requires mental stamina. Feeling mentally drained will impact your mood and we all know that missing out on a good nights rest can alter how we think and feel. People who sleep for less than five hours are often sadder, angrier and more stressed (2) which is linked with low motivation and decreased sports performance (5).

Endurance performance

Not a lot is known about sleep deprivation and its effect on short, sharp, anaerobic power type exercise, but a number of studies have shown decreased endurance performance (6, 7, 8, 9).  Sleep loss clearly resulted in increasing 3km time trial duration in cyclists (7), decreased time to exhaustion in volleyball players (6) and decreased treadmill run distance covered in a 30 minutes self-paced test (9). This appears to be due to an increase in our perception of effort (how hard you feel you're working) (8). It may also be due to an alteration in substrate availability as pre-exercise muscle glycogen (our carbohydrate fuel tank) has been found to be decreased after sleep deprivation (10). 

Improve sleep efficiency

Multiple studies show the significant implications sleep deprivation has on performance. From impaired accuracy, coordination and reaction time, fatigue, inadequate recovery, to increased risk of injury and illness. So what can we do to improve our sleep efficiency - both duration and quality?

  • Get to bed earlier, aiming to get 7-9 hours of sleep every night.
  • Stop using your phone in bed. The blue light it emits affects our normal sleep hormone production (melatonin)
  • Ensure all of your devises are set up with night mode so they switch to a more warm, orange hue after sunset.
  • Make your sleep environment comfortable, dark, cool and quiet
  • Establish a regular sleep routine
  • Eat foods that assist with promoting sleep - more on this next time!

Next up - we take a look at food to boost sleep performance. Stay tuned!

 

References

 1. Hirshkowitz et al., (2015). National Sleep Foundation's updated sleep duration recommendations: final report. Sleep Health: The Journal of the National Sleep Foundation. 1(4), 233-243

2. Bird, S, P. (2013). Sleep, recovery, and athletic performance: a brief review and recommendations. Journal of Strength and Conditioning. 35:43-47.

3. Williamson, A., Feyer, A. (2001). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and Environmental Medicine, 57: 649-655.

4. Prather, A., Janicki-Deverts, D., Hall, M. and Cohen, S. (2015). Behaviuorally assessed sleep and susceptibility to the common cold. Sleep. 38: 1353-1359.

5. Totterdell, P., Reynolds, S., Parkinson, B., & Briner, R. (1994). Associations of Sleep with Everyday Mood, Minor Symptoms and Social Interaction Experience. Sleep, 17(5), 466-475.

6. Azboy, O, Kaygisiz Z. (2009). Effects of sleep deprivation on cardiorespiratory functions of the runners and volleyball players during rest and exercise. Acta Physiologica Hungarica. 96, 29-36.

7. Chase et al. (2017). One night of sleep restriction following heavy exercise impairs 3-km cycling time-trial performance in the morning. Applied physiology, nutrition, and metabolism. 1-7

8. Fullagar, H, H, Skorski S, Duffield R, et al. (2015). Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports Med. 45, 161-86.

9. Oliver, S, Costa, R, Laing, S, et al. (2009). One night of sleep deprivation decreases treadmill endurance performance. European Journal of Applied Physiology. 107, 155-61.

10. Skein, M, Duffield, R, Edge, J., et al. (2011). Intermittent-sprint performance and muscle glycogen after 30 h of sleep deprivation. Medicine and Science in Sports & Exercise; 43: 1301-11.

11. Watson, A. (2017). Sleep and Athletic Performance. Current Sports Medicine Reports, 16(6), 413-418.

The Different Stages of Sleep

Many of us think of sleep as a time when the mind and body shut down, but in fact what happens when our head hits the pillow is quite the opposite. Sleep is a dynamic process – our brain changes its state many times as we pass through the five stages of sleep in approximately 90-minute cycles. The first four stages of sleep make up our non-rapid eye movement (NREM) sleep and the fifth stage is when rapid eye-movement (REM) sleep occurs.

Across NREM sleep we move from very light sleep during Stage 1 to very deep sleep in Stage 4. It’s very difficult to wake a person who is in Stage 4 sleep. Typically, our eyes do not move during NREM and we have low muscle activity, although all of our muscles are still able to function.

                Stage 1 – Very Light sleep: We drift in and out of sleep and can be awakened easily.

                Stage 2 – Light sleep: Where eye movement ceases.

                Stage 3 & 4 – Deep sleep: We’re difficult to wake and have no eye movement or muscle activity.

                Stage 5 – REM sleep

During Stage 5 or REM sleep our brain waves are as active as when we are awake and breathing becomes more rapid. The limb muscles are temporarily paralysed, our body does not move, eyes can dart rapidly in all directions and we dream vividly.

A typical night under the covers isn’t simply four to six of these 90-minute sleep cycles pieced together. In the first two to three cycles of shut-eye we spend most of our time in deep Stage 3 and Stage 4 (NREM) sleep. During the final two to three cycles we enter more REM sleep which is accompanied by some lighter NREM sleep. 

Cycling through the sleep stages is important for preventing tiredness and irritability the next day and maximising the benefits of sleep. Next up, we’re taking a look at how sleep can boost performance. Stay tuned!

Stay well this winter - Top 5 Tips to Surviving the Cold and Flu Season

With the cooler weather setting in, the cold and flu season is upon us. There’s nothing worse than getting sick, especially right before a key event! Here are our top five tips for looking after your immune system and staying well this winter.

Staywellthiswinter

1. Get your 2 fruit and 5 veggie serves in each day

Vitamins and minerals are important for a huge range of reactions within the body such as growth and repair, muscle function, energy metabolism and protection from free radical damage. If we don’t get enough of certain nutrients, our health and performance suffers. It also increases your risk of getting sick. That doesn’t mean you need to start sucking back the multivitamins. Focus on getting a variety of nutrients each day from fresh fruits and vegetables. The more colours, the better to ensure you’re getting a wide range of important, sickness busting vitamins and minerals.

Keep up your daily dose of 2 serves of fruit and 5 serves of vegetables during the comfort food season with these ideas:

  • Go for warm salads with plenty of roasted vegetables like zucchini, eggplant and capsicum, red onion.  
  • Try vegetable soups loaded up with all of the leftovers in the fridge at the end of the week. These will keep you warm from the inside and provides loads of nourishment. Be sure to include a protein source though if this is your main meal.
  • Baked fruits like apples, pears and stone fruit make perfect snacks with a little Greek yoghurt on top.

 

2. Get enough sleep

Despite what some people think, most adults need between 7-9 hours of sleep each night. If you’re sleep deprived and run down you increase your risk of getting sick. Sleep is your ultimate form of recovery, so if you’re not getting enough, you may actually be blunting the effect of training and increasing your risk of picking up the next bug.

Turn your screens off early as the blue light emitted from phone and computer screens affects your natural sleep hormone, melatonin. Set night shift on your phone to start from 6pm which shifts the colour of your screen to the warmer end of the colour spectrum. This may help you sleep better. Get out of the habit of scrolling through Instagram before bed. Read a book instead to relax and wind down.
 

3. Stress less

High stress levels are well documented as being immunosuppressive.  Stress hormones such as cortisol, adrenaline, noradrenaline and prolactin are influenced by negative events and negative emotions, inducing adverse immunological changes.

The longer you’re stressed for (1 month or more) and the more often you’re stressed appears to be directly related to increased incidence of developing cold and flu symptoms.

Life is sometimes stressful – we get it. If you feel your stress levels getting out of hand, find ways to manage this that works for you. Do some exercise, yoga, meditation, go for a walk, read a book, call a friend, take a holiday!

 

4. Look after your gut micro-biome

Your gut plays a huge role in maintaining your immune function. Look after it to prevent picking up colds and flu’s this winter.

Promote balance of good bacteria by eating lots of fresh fruits, vegetables, wholegrains, legumes, yoghurt with live cultures and fermented foods such as tempeh, miso, kimchi and sauerkraut. Take antibiotics only when they are necessary. Remember, antibiotics won’t help you if you have a virus such as a cold or the flu.

Probiotic supplements also have proven benefit in maintaining gastrointestinal function and positively affecting immunity. If you travel a lot or have a key event coming up, talk to a sports dietitian about whether it’s worth taking a probiotic supplement to support your immune function.

 

5. Be hygienic

This shouldn’t be news by any means, but good health habits like covering your cough and washing your hands frequently can help stop the spread of germs and prevent getting sick. Germs are often spread when a person touches something that is contaminated and then touches their eyes, nose or mouth. Prevention is key.

  • Wash your hands often with warm water and soap, especially before eating.
  • Clean and disinfect surfaces frequently, especially when someone is sick.
  • Dispose of tissues hygienically, don’t leave them lying around.
  • Don’t share cutlery, glasses or water bottles with someone that is sick (or well for that matter)
  • If family or friends are sick, give them space and be extra careful with hygiene
  • If you fly frequently, don’t touch your eyes, nose or mouth unless you’ve washed your hands with warm water and soap.

 

If you do feel like you’re coming down with something, there’s good evidence to suggest Vitamin C and Zinc can help prevent or decrease the severity of a cold or flu. Check with your GP or Sports Dietitian to see if this is a good idea for you.

Stay well guys!