Your chronotype and your sleep debt

Chronotype

Your internal clock has a genetically influenced position. It is neither a choice nor a character trait.

Early, about fifteen per cent: spontaneous waking between 5 and 6.30 am, cognitive peak in the morning, falls asleep easily before 10.30 pm. Intermediate, about sixty per cent: waking between 6.30 and 8 am, peaks in the late morning and the late afternoon. Late, twenty to twenty-five per cent: struggles to fall asleep before midnight, cognitive peak in the evening, painful waking before 8 am.

Adolescents and young adults are physiologically shifted towards the late type, which corrects itself naturally with age.

The simple test

One question, the most predictive: on days with no constraints at all, what time do you fall asleep and wake up spontaneously?

The midpoint of that period is your natural mid-sleep. Before 3.30 am, you are early. Between 3.30 and 5 am, intermediate. After 5 am, late.