All About Sleep

Sleep is a highly sought, frequently underachieved necessity of life. And yet, people don't really know what's going on when they're asleep. Probably because they're... well... asleep.

Sleep is an immediately reversible, perceptual wall between the conscious mind and the outside world, and contains four stages.

Stage One: Transition.

  • Comprises 4-5% of total sleep time.
  • Muscle activity slows. 
  • Twitching.

Stage Two: LIght Sleep.

  • Comprises 45-55% of total sleep time. 
  • Breathing and heart rate slow. 
  • Body temperature drops.

Stage Three: Slow Wave

  • Comprises 16-21% of total sleep time. 
  • Rhythmic breathing. 
  • Limited muscle activity. 
  • Brain produces delta waves.

Stage Four: REM

  • Comprises 20-25% of total sleep time. 
  • Rapid eye movements. 
  • Brainwaves speed up. 
  • Dreaming. 
  • Muscles relax. 
  • Heart rate increases. 
  • Breathing rapid and shallow.
  • Bloodflow to the brain increases, increasing brain temperature.
  • Muscles are paralysed.
  • Dreams (80% recall).

So how do you know if you're getting enough sleep? Australian, Dr. Murray Johns developed the Epworth Sleepiness Scale. This questionnaire measures the probability of falling asleep in eight different situations, then adds the numbers to give you a final score. Take the test below.

The Epworth Sleepiness Scale:

How likely are you to doze off or fall asleep in the following situations? Choose the most appropriate number for each situation:

0 = no chance of dozing
1 = slight chance of dozing
2 = moderate chance of dozing
3 =  high chance of dozing

  1. Sitting and reading
  2. Watching TV
  3. Sitting innactive in a public place (eg: cinema or meeting)
  4. As a passenger in a car for an hour without a break
  5. Lying down to rest in the afternoon when circumstances permit
  6. Sitting and talking to someone
  7. Sitting quietly after a lunch without alcohol
  8. In a car, while stopped for a few minutes in traffic

Now add up your scores.

1-6 = You're getting enough sleep.
7-8 = Your score is average.
9 and up = seek the advice of a medical specialist.

Sleep is important. The effects of sleep loss are highly influential on waking performance. They include:

  • Impaired judgement.
  • Reduced creativity.
  • Reduced concentration.
  • Reduced language and communication skills.
  • Slowed reaction times.
  • Reduced ability to learn and remember.
  • 20% increase in physical problems.

Ensure you get enough sleep to correct the above deficits. If you feel you aren't getting enough sleep and you need the skills outlined above, the points in your circadian rhythms where the brain is programmed to be awake are several hours before your usual bedtime and six hours after the low point of temperature (late morning). The easiest times to fall asleep are 3am-5am (at the temperature low point) and in the mid afternoon (9-10 hours after the temperature low point).

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Dan Williams

Dan Williams is the Founder and Director of Range of Motion. He is an Accredited Exercise Physiologist and Exercise Scientist with a Bachelor of Science and a Bachelor of Exercise Rehabilitation Science. Dan is a CrossFit Coach (at CF Games Level) and four time CrossFit Regionals Athlete.