While even experts haven’t reached a consensus explanation for why we sleep, numerous indicators support the view that it serves an essential biological function.

In adults, a lack of sleep has been associated with a wide range of negative health consequences including cardiovascular problems, a weakened immune system, higher risk of obesity and type II diabetes, impaired thinking and memory, and mental health problems like depression and anxiety.

The body regulates sleep with two key drivers:

1. Sleep-wake homeostasis. The longer you’re awake, the more you feel a need to sleep. This is because of the homeostatic sleep drive, the body’s self-regulating syste...