Sleep Disorders

Updated 11 August 2014

6 facts about sleep

Sleep may be world’s ultimate leveller. Whether you’re billionaire or celebrity, sleep is something everyone has to have.


Sleep may be world’s ultimate leveller. Whether you’re a billionaire or celebrity – sleep is something everyone has to have. Here are some fascinating facts.


  1. The body’s response to external things, such as sunlight, is monitored by it’s internal clock, called the circadian clock (circadian comes from a Latin word meaning ‘‘around the day’’).

  2. The circadian clock is situated in the in the hypothalamus and is the size of a pinhead.

  3. Because of the body’s circadian clock there’s a greater risk of dying between 4-6 am.

  4. Most heart attacks occur in the early hours of the morning.

  5. Your body weight is at its lowest between 9 am and noon while reaction time peaks at about 4 pm.

  6. Asthma attacks typically happen between midnight and 6 am and most women give birth naturally around 1 am.


(This is an edited version of a story that originally appeared in YOU Pulse / Huisgenoot-POLS magazine, Winter 2008. Buy the latest copy, on newsstands now, for more fascinating stories from the world of health and wellness.)

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Sleep disorders expert

Dr Alison Bentley is a general practitioner who has consulted in sleep medicine and sleep disorders, in both adults and children of all ages, for almost 30 years. She also researches and publishes on a number of sleep-related topics both in formal research journals and lay publications including as editor of Sleep Matters, an educational newsletter on sleep disorders for doctors.

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