Early Birds, Night Owls, & Thirdbirds
Your chronotype determines is where the peak/trough take place in the day. The chronotypes follow a left-skewed normal distribution. Roughly, 30% are early birds, 50% are “third birds”, and 20% are night-owls. The measuring method is to find the midpoint of your average night’s sleep. Early birds have a midpoint before 4am. Night owls have a midpoint after 6am. Most people fall in-between. Midpoints tend to be earlier in early and late life, and much later around the teenage, early 20’s years.