Seven hours of sleep is perfect for the human brain.
Seven hours of sleep is the sweet spot for the brain
Experts have claimed that any more or less slumber can cause dementia and mental health problems and are convinced that they have found the sweet spot for a healthy night's sleep.
Deep sleep cleans the brain of proteins that can cause damage and also allows the body to connect and repair nerves to store memories.
Since this is a gradual process, scientists have recommended seven hours in bed.
Brain scans of 500,000 Brits aged between 38 and 73 showed that those who slept longer or got up earlier scored lower on thinking tests and were at a greater risk of dementia.
Professor Barbara Sahakian, from Cambridge University, told the journal Natural Aging: "Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and avoid cognitive decline."