Chronotype Quiz: Find Your Sleep Type

A chronotype is your biologically determined preference for when to sleep and wake, driven primarily by genetics, modified by age. It determines when melatonin rises, when cortisol peaks, and when your brain performs best.

You can shift your sleep schedule 1 to 2 hours from your natural timing using light therapy and consistent scheduling. But your fundamental chronotype is genetically fixed, you can work around it but cannot fundamentally change it.

Shift it by 15 to 30 minutes every two or three days while keeping the wake time fixed, get bright light after waking and dim lights for an hour before bed.

CDC guidance lists 8 to 10 hours for ages 13 to 18, 9 to 12 hours for ages 6 to 12, 10 to 13 hours for ages 3 to 5 including naps, and 11 to 14 hours for ages 1 to 2 including naps.

A cycle moves through lighter NREM sleep (N1 and N2), deep slow wave sleep (N3) and then REM sleep. Early cycles contain more deep sleep, while later cycles contain more REM, which is why the last hours before waking are valuable for dreaming and memory processing.

Move your schedule by 15 to 20 minutes over several days before the change and get morning light afterwards. Expect a few days of adjustment.

The American Academy of Sleep Medicine and Sleep Research Society recommend at least 7 hours a night for adults. The National Sleep Foundation suggests 7 to 9 hours for most adults and 7 to 8 hours for people 65 and older. Some people need more, and you can judge your own need by how you feel on days you are not sleep deprived.

Most adults do well with 5 cycles (about 7.5 hours) and some need 6 (about 9 hours). Four cycles, about 6 hours, is short for most people and is better used as an occasional fallback than a habit.