Chronotype

Chronotype is the individual disposition toward earlier or later sleep-wake timing, commonly described as morning, intermediate, or evening type. It is shaped by genetics, age, light exposure, and social schedules. Chronotype influences cognitive peak times, athletic performance, and cardiometabolic risk, and a mismatch with imposed work or school hours, known as social jetlag, has been linked to obesity, mood disorders, and impaired metabolic health.