Sleep, screens and movement: what the evidence says

New Zealand's health guidelines for children and young people aged 5 to 17 are called 'Sit Less, Move More, Sleep Well'. They describe a balanced day: enough sleep, plenty of movement and not too much sitting.

The guidelines

Why sleep matters so much

Sleep is when your body grows and repairs itself. While you sleep, your brain sorts and stores what you learned that day, which is why a good night helps with tests. Too little sleep makes it harder to concentrate, control your temper and make good choices. It can even make you hungrier for sugary food the next day.

Your moving body clock

You have a body clock that tells you when to feel sleepy. It works partly through a hormone called melatonin, which rises in the evening when it gets dark. During puberty, the clock shifts later, so many young people don't feel sleepy until later at night, but still have to get up early for school. That is biology, not laziness. Bright screens in the evening can push the clock even later, because the light tells your brain it is still daytime.

Using guidelines well

Guidelines describe what helps most people. Your goal is to improve on your own starting point, not to match anyone else. Some things aren't fully in your control, like a noisy house or a shared room, so focus on what is. Small changes that you can keep going, such as charging your phone outside your bedroom, beat big changes that last a week.