LOOK ON THE LIGHT SIDE

Whether or not you have something you’d consider a bedtime routine, it’s almost certain that the last thing you do before you fall asleep is turn out the light. We all understand that it’s easier to sleep when it’s dark, but the relationship between light and sleep is much more important than you might imagine.

The invention of artificial light means society and the human body are no longer reliant on the natural prompts of dawn and dusk to wake up and fall asleep. And yet despite the lure of late-night videogame sessions, the necessity of working late at your laptop or the urge to get to the gym before the sun’s up, your body’s internal clock will still be working to a more fundamental timetable that’s closely tied to natural light.

Dr Vikki Revell is a chronobiologist at the University of Surrey and studies the non-visual effects of light on physiology, behaviour and sleep patterns. She