Three scientists who unravelled how our bodies tell time have won the 2017 Nobel Prize for physiology or medicine.
The body clock – or circadian rhythm – keeps us in tune with the movement of the Earth and drives huge changes in the way our bodies 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”.
The body clock is the reason we want to sleep at night. But it also affects our mood, alertness and even the risk of a heart attack in a daily rhythm.
Juleen Zierath, from the Nobel Assembly, said: “What it can do is raise awareness to the proper importance of sleep hygiene and the importance of really making certain we allow ourselves to go to bed at an hour that’s suitable.”