Sweet spot for sleep

All right, I'm about to reveal the sweet spot for sleep that will help you maintain good mental and physical health. Once we reach middle age, we need to sleep a certain number of hours each night to maintain good health.

That number is seven hours, no more, no less. Researchers at the UK's University of Cambridge, they analyzed data from nearly half a million people between the ages of 38 and 73. The result, seven hours a night was the optimal amount of sleep for cognitive performance.

The data also showed that fewer than seven hours of sleep and more than seven hours was linked to reduced mental processing speed, visual attention, memory, and problem-solving skills. Study participants who slept seven hours a night, they also experienced less anxiety and depression and higher overall well-being compared to when they slept longer or shorter periods of time.

Pretty amazing, right? The researchers say one reason is that getting less than seven hours a night means people are getting less deep sleep. And without that restorative deep sleep, damaging proteins build up in the brain, which is one of the hallmarks of dementia.

Too little sleep also hurts the brain's ability to flush out toxins, which can trigger inflammation and age-related brain diseases. And sleeping more than eight hours a night after middle age is actually linked to depression. If you want to maximize your brain function in middle age and beyond, seven hours is your sweet spot.