Cancer, heart disease, type-2 diabetes, infections and obesity have all been linked to reduced sleep.
The body clock drives huge changes in the human body. It alters alertness, mood, physical strength and even the risk of a heart attack in a daily rhythm. It stems from our evolutionary past when we were active in the day and resting at night.
But scientists have warned that modern life and 24-hour society mean many people are now “living against” their body clocks with damaging consequences for health and wellbeing.
Prof Russell Foster, at the University of Oxford, said people were getting between one and two hours less sleep a night than 60 years ago.
Emerging evidence suggests modern technology is now keeping us up later into the night and cutting sleep.