Circadian Rhythms
Sleep is mainly controlled by two things: sleep pressure and your body clock, also known as the circadian rhythm.
Your body clock follows a 24‑hour cycle and helps control many important processes, including when you feel awake and when you feel sleepy, but also your eating habits and body temperature. It responds to changes around you, especially light and dark, so your body can prepare for the day ahead.
In an ideal situation, your body clock naturally helps you wake up in the morning and feel alert during the day. As the day goes on, sleep pressure slowly builds. After around 15 hours of being awake, this pressure becomes strong, and you start to feel tired. When it gets dark, your body clock lowers alertness and helps you stay asleep through the night.
How to strengthen your body clock to develop a regular sleep and wake up time
Bedtime
Keeping a regular sleep routine is important. Waking up at the same time each morning helps keep your body clock strong and steady — even at weekends.
Light
Morning light is especially powerful. A short walk outside in the morning can help reset your body clock and give you a natural energy boost. In the evening, it’s best to reduce exposure to bright light.
Screen time
Because your body clock takes cues from things like light, darkness and temperature, it can make winter tricky, as we spend more time in the dark. We often feel more alert when it’s bright outside, and sleepier when it’s gloomy and dark.
Sometimes our body clocks get out of sync and this is when problems can occur. This can happen when your biological clock is not lined up with the day-night cycle, the clocks change, when travelling across time zones (jet lag) or with shift work. Without the right signals, sleep, appetite, mood and focus can all suffer.
By paying attention to your natural patterns of sleepiness and alertness — and by sticking to good sleep habits — you can help your body clock work better and enjoy more restful, refreshing sleep.