The Atlantic: Some ultra-introverts choose to live nocturnal lives, but is it healthy?

Ideal sleep hours vary from person to person, but most people naturally follow a similar circadian rhythm and wake during daylight. Messing with that internal clock can wreak havoc on your health: Circadian-rhythm disruptions are associated with increased risk of Type 2 diabetesheart diseasegastrointestinal disorders, and cancer. Some people I spoke with told me they sometimes have trouble falling asleep and have had to intentionally train themselves for nocturnal living: They have to be disciplined about getting good sleep in the daytime, using blackout curtains or white-noise machines and putting all their devices on silent. But it may still be hard on their bodies.