Three scientists who unravelled how our bodies tell time have won the 2017 Nobel Prize for physiology or medicine, BBC News reports.
The body clock – or circadian rhythm – is the reason we want to sleep at night, but it also drives huge changes in behaviour and body function.
The US scientists Jeffrey Hall, Michael Rosbash and Michael Young will share the prize.
The Nobel prize committee said their findings had “vast implications for our health and wellbeing”.
A clock ticks in nearly every cell of the human body, as well as in plants, animals and fungi.
Our mood, hormone levels, body temperature and metabolism all fluctuate in a daily rhythm.
Even our risk of a heart attack soars every morning as our body gets the engine running to start a new day.