“And you will really struggle to get up on Monday morning and this is particularly true of teenagers.”
As part of Dr Mosley’s research, he also did a “big” sleep census, involving more than 200,000 people.
The doctor said: “We found that the average amount of sleep people reported was really quite short – it was six hours and 58 minutes.
“Our experts thought that was pretty low. Ideally, you’re between seven and nine hours.
“And if you’re a teenager, between eight and nine hours.”