Columbia scientists: 6.4–7.8 hours of sleep is optimal — less or more accelerates aging

Researchers at Columbia University analysed data from nearly half a million people, examining the biological ageing rate of 17 organ systems including the brain, heart, lungs and immune system. They found the slowest ageing in people sleeping between 6.4 and 7.8 hours per night. Both too little and too much sleep were linked to accelerated ageing.