Body clocks: understanding what makes them tick

Posted in Rest Bites |
Key Facts: 
  • The suprachiasmatic nucleus (SCN) is a little area of the brain that controls our sleep and wake cycles
  • Every major organ in the body also contains a 'clock' that is controlled by the SCN
  • Avoiding artificial light and maintaining regular sleeping and eating routines is the best way to keep your clocks in sync
  • If the clocks become dysregulated it can lead to poor health


All species across the animal kingdom (humans included!) have a 24-hour rhythm that’s determined by our genes.  In humans we know our rhythm is controlled by a tiny little area in our brain called the suprachiasmatic nucleus (SCN).  The SCN receives information through our eyes, specifically when light hits the retina, and this is how our bodies monitor sleep and wake cycles.

What’s interesting is that all the major organs in the body also contain a type of clock directly controlled by the SCN.  So light hitting the eye tells the SCN to activate the organs that should be ‘awake’ and active during the day.  Darkness does the same thing, so the organs and body systems we need to be active at night should receive orders on when to start work by the SCN.  Not only does light synchronise the activity in the body, social routines do too.  Even if we had no light, we could still maintain a normal 24-hour rhythm if we stuck to an existing routine, such as eating and going to bed at the same time.  That’s why it’s so important not only to get natural light, but to avoid artificial light and maintain a bedtime routine wherever possible.

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