Basics
Your body clock 101: light, melatonin, timing
You have a master clock in your brain that runs on roughly a 24-hour cycle. It decides when you feel alert and when you feel sleepy — and it takes its cues mostly from light.
How it works
Morning light hits your eyes and tells the clock "it's day" — shutting off melatonin and starting your alert cycle. As darkness falls, melatonin rises and the clock says "wind down." Modern life scrambles this: dim mornings indoors, bright phones at night, and irregular schedules all confuse the signal.
Reset it on purpose
- Morning light is the master switch. 10–15 minutes of outdoor light within an hour of waking anchors the whole day and helps you sleep that night.
- Dim the evening. Lower the lights an hour before bed so melatonin can rise on schedule.
- Keep timing consistent. A regular wake time is the single strongest anchor — it stabilises everything downstream.
Melatonin is a timing signal, not a sedative. It tells your body when to sleep, not how to knock you out — which is why light habits often beat pills.
This article is general sleep education, not a diagnosis or personalised medical advice. If sleep problems persist or worry you, please consult a licensed physician.