What makes for a good night's rest?

摘要

To reap the benefits of a good night's rest, there are three things you need to consider, says Charles Czeisler at Brigham and Women's Hospital and Harvard Medical School in Boston: how much you sleep, how well, and when. Carving out the time to visit the land of nod is one thing, but guaranteeing good quality rest can be beyond our control. For instance, people often sleep poorly their first night in a new place. To find out why, Masako Tamaki and colleagues at Brown University in Rhode Island recently scanned people's brains as they slept in unfamiliar places, then again when those spots had become familiar. In the first scenario, the team found that parts of one hemisphere of the brain remained active while the participants were asleep. This "first-night effect" may be an evolutionary adaptation, keeping part of your brain alert to make sure the new environment is safe. "We call this system the night watch," Tamaki says.