The Conversation asks: How much sleep is needed for senior executives such as our president to have optimal function?

As a neurologist who has studied sleep for many years, I know that sleep affects our functioning and health. While a very small percentage of people can function with four or five hours of sleep a night, most of us need much more.

Scientific research has yet to lead to a “grand unified theory” for the evolutionary purpose and function of sleep, but studies have shown several important functions sleep has on our body and brain. Based on a meta-analysis of medical research literature, the American Academy of Sleep Medicine and the Sleep Research Society jointly released a consensus statement last year recommending that adults receive at least seven hours a night to maintain optimal health.