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TSN Running Science: Sleep - Training with your Eyes Closed

Published on December, 20th 2013
By Dr. Greg Wells

By: Greg Wells PhD and Jessica Caterini BSc

There is a reciprocal relationship between sleep and exercise.  If  you sleep properly, you will probably perform well during your next  workout or race, and if you exercise regularly, you will be able to  sleep well.  By understanding and applying the science of sleep, you  will know how to optimize your health, fitness and performance.

Sleep 1

How Sleep Works

Scientists recommend that people get between 7 and 9 hours of sleep  per night because that is the amount of time required for all of the  critical sleep-based recovery processes to occur. A very lucky and small  percentage of the population has a gene that allows them to recover  fully on about 4 hours of sleep – but the rest of us need much more!  When you sleep, your body takes advantage of the regenerative processes  that occur during this highly relaxed state.  Acute exercise experiments  that have measured sleep physiology directly from subjects who either  performed, or refrained from, daytime exercise indicate that exercise is  associated with a small, but reliable increase in Stage 2 and slow wave  sleep.1  Exercise may improve sleep quality by regulating body  temperature although the exact physiology to explain how exercise  improves sleep is still being explored by researchers. However, because  body temperature does play a key role in sleep, it has been suggested  that people should sleep in a cool room that is about 21 degrees C.

One example of a critical restorative process that occurs while you  are sleeping is the release of Human Growth Hormone (HGH).  HGH promotes  fat breakdown and increases in muscle mass, which allows the body to  recover from the physiological stresses that occur during training.  If  you are sleep deprived and have less HGH in your system, not only will  you restrict your body’s ability to recover while you are sleeping, but  it also appears that you will limit your ability to exercise the next  day.  Lower levels of HGH may decrease the amount of time an athlete can  exercise at maximum effort due to reduced energy stores in their  muscles.2

One of the most important things to know about sleep is that it is  critical that you attain a highly relaxed state while sleeping.  This  means limiting the amount of stress in the hours leading up to when you  want to fall asleep.  The problem with stress goes beyond lying awake  thinking about whatever is causing you stress.  When you are in a  stressed state, you secrete increased levels of a hormone called  cortisol into your body and your body can respond to the apparent stress  with changes like increased blood pressure and more rapid processing of  glycogen. Cortisol is really helpful when you are faced with a  stressful situation – like meeting a deadline or saving your family from  a sabre tooth tiger – but it inhibits the adaptive processes of your  body.

The mental effects of sleep are well known to all of us.  If we are  well rested, we are more able to cope with life’s stresses, stronger and  more effective in our exercise, sharper in our work and just plain more  fun to be around.  The catch is that the North American attitude toward  sleep tends to be that it isn’t particularly important.  As you plan  for your next race, or even if you are just reassessing your life in  general, the more you can commit to getting a proper amount of sleep,  the healthier and more effective you will be.

What The Research Tells Us

Some research on sleep that is relevant for runners has to do with  understanding the ideal conditions for a good night’s sleep so that you  can promote the secretion of key hormones that regulate sleep, in  particular melatonin.  Melatonin is produced by your pineal gland, which  is located deep inside your brain, and organizes the sleep cycle by  controlling sleep-wake cycles.  Because the pineal gland responds to  light via neurons that project from your eyes, you have to ensure that  you are in a dark space while you sleep.  You also need to limit your  use of your TV or computer since looking at a bright screen may disrupt  sleep patterns by inhibiting the release of melatonin. Time to cut out  the late night talk shows!

An interesting finding related to sleep and eating is that research  is discovering links between sleep and weight loss.  The conclusions are  only beginning to form but it appears that there are hormones released  while we are sleeping that help to regulate our weight.  Not to mention  that you are less likely to dive into the sugar and fat to keep yourself  going if you are exhausted.

It is also important to avoid caffeine within six hours of heading to  bed as caffeine (coffee, tea, green tea, chocolate etc…) will disrupt  sleep patterns.  In terms of the timing of your sleep, there is also an  increasing body of evidence that suggests that sleeping on a regular  schedule is even more important than the total amount of time you are  asleep.  Studies show that when an athlete’s bed time is shifted around  but the total number of hours they sleep remains the same, there is a  measurable decrease in athletic performance.  So sticking to a  consistent routine is critical.

Improve Your Sleep Performance

Personally, I recommend people get 8 hours on a consistent basis. I  also recommend sleeping between 10 pm – 6 am to ensure at least 2 hours  of sleep before midnight to allow people to get their 8 hours in while  still having time to wake up early and get that morning run in. To  ensure that you get the best quality sleep you can, keep the following  things in mind:

– Keep your stress levels to a minimum, especially in the hours before sleeping

– Sleep in a room that is as dark as possible – even clock lights can be a problem

– Avoid screen time within 45 minutes of going to bed

– Keep the room you sleep in at roughly 21 degrees Celsius

– Try to maintain a consistent sleep schedule

– Try to get into bed a couple of hours before midnight

– Avoid caffeine within six hours of going to bed

References

1http://ukpmc.ac.uk/abstract/MED/7556348/reload=0;jsessionid=Z7aUGPsjR61IBT5vKEX5.22

2 VanHelder T, Randomski MW (1989).  Sleep deprivation and the effect on exercise performance. Sports Medicine 7(4):235-247.