Can you change your chronotype, or do you have to live with it?

Michael J. BreusPhD · clinical psychologist (NPPES taxonomy 103TC0700X, Arizona licence 3760, record last updated 26 Nov 2012) · Diplomate of the American Board of Sleep Medicine, specialty Psychology, certified 17 Apr 2000, a lifetime credential with no expiry and no recertification · stated Fellowship of the American Academy of Sleep Medicine, a voluntary association, not verified

You cannot. It is genetic, and retraining it is next to impossible.

What it rests onHe separates chronotype from circadian rhythm explicitly and puts the lever on only one of them: circadian rhythm can be retrained, and he gives night-shift adaptation with bright light and blackout curtains as the worked example, but 'Unlike circadian rhythm, your chronotype is influenced by genetics, not light or other environmental factors', naming PER3 and shorter alleles, and 'deliberately changing or retraining your chronotype is next to impossible'. The same paragraph concedes that 'your chronotype may evolve over the course of your life', which belongs with the claim. His 2026 page states the position more firmly still, as 'Your genetic, pre-determined sleep schedule', with no new evidence cited.

Jade WuPhD, DBSM · behavioural sleep medicine psychologist

You can shift it, and here is how.

What it rests onShe argues chronotype is 'determined by our genes, age, environment, and behaviors' and 'shifts across our lifetime', that night owls are not lazy, and that research linking late chronotypes to poor health mostly reflects the damage of forcing a late chronotype into an early world rather than anything wrong with the chronotype itself. Her practical instruction is the lever Breus says does not exist: if you are 'a night owl with morning obligations, you can shift your chronotype by consistently getting up at the same time every morning (including weekends!) and getting bright light exposure as early as possible upon waking'.