Screens, Sleep, and Your Amazing Brain

Think about the last time you used a screen — a phone, tablet, TV, or computer — close to bedtime. Did you find it hard to fall asleep afterwards? You are not alone. Millions of children around the world lie awake after screen time, wondering why their brain just will not switch off. In this lesson you will find out exactly what is happening inside your body — and what you can do about it.

**Your body's sleep clock** Your body has a built-in clock called the circadian rhythm (say: sir-KAY-dee-an RY-thum). This clock tells your brain when to feel sleepy and when to feel awake. It mainly works by sensing light. When it gets dark, your brain makes a chemical called melatonin (mel-ah-TOH-nin). Melatonin is the 'sleep signal' — it makes you feel drowsy and ready for bed. **The blue light problem** Screens give off a type of light called blue light. Blue light has a short, high-energy wave. Your brain cannot tell the difference between blue light from a screen and the bright blue light of daytime sky. So when you look at a screen in the evening, your brain thinks it is still daytime. It slows down melatonin production. You feel awake instead of sleepy, even when your body is tired. **Your brain stays 'switched on'** Screens do not just affect your eyes. Games, videos, and messages also excite your brain. Your heart beats a little faster. Your thoughts race. This makes it even harder to wind down. **How much sleep do you need?** Children aged 6–12 need about 9–11 hours of sleep each night. Sleep helps your brain store memories from the day, repair your body, and regulate your mood. Missing sleep regularly makes it harder to concentrate and can make you feel grumpy or sad. **Screen habits that help** The good news is that small habits make a big difference: • Stop using screens at least 1 hour before your planned sleep time. • Charge devices outside your bedroom overnight. • Use night mode or warm-light settings if you must use a screen in the evening — this reduces blue light. • Replace screen time before bed with calm activities: reading a book, listening to quiet music, or talking to family.