FOUR STEPS TO RESET YOUR CLOCK EVERY DAY

THIS series is packed with practical advice for harnessing your body clock to boost health and happiness. But you can start straight away with these simple steps:

GET 30 MINUTES OF LIGHT AT DAWN AND DUSK

TO KEEP our body clock in sync, we need to ‘reset’ it every day — the best way to do this is to get natural light 30 to 60 minutes after sunrise and before sunset (later than dawn is still OK, see main story).

DON’T FRET ABOUT BLUE LIGHT FROM SCREENS

THERE have been a lot of warnings about not using screens before bed — the idea is that the artificial blue light they emit tells your body the wrong time, and shifts your clock later.

In fact, the light from something like a Kindle or iPad is much, much weaker than dawn light, and one key study showed that four hours of use immediately before bedtime on five consecutive nights delayed sleep onset by only a few minutes, which is essentially meaningless. The real problem with late-night use of technology is that it increases mental alertness. This is what actually delays sleep.

DON’T GO TO SLEEP ON AN ARGUMENT

TALKING to your partner in bed about problems might seem like a great way to catch up, but any disagreement increases levels of the stress hormones cortisol and adrenaline. This will delay and shorten sleep, and alter your body clock rhythms. So leave difficult conversations for the daytime and save bed for intimacy (sex lowers cortisol and makes you relaxed and sleepy).

STICK TO REGULAR SLEEP ROUTINE AND NO LIE-INS

KEEP to a regular schedule on weekdays and at weekends. By catching up on sleep at weekends you’re missing the morning light, which means you’re not resetting your body clock.

This means that by Monday your body clock will be slightly out of kilter, making life more difficult in the long run.