Circadian Score
0 to 100 composite
A measure of how well your sleep schedule aligns with your natural circadian rhythm. Higher scores indicate more consistent, biologically-timed sleep.
Typical optimal range 80 - 100
Population median 72
Key factors
- Shift work and rotating schedules
- Daytime light exposure and outdoor time
- Consistency of bedtime and wake time
What affects this metric
- Morning light exposure is the strongest anchor for circadian timing.
- Shift work is the largest single disruptor of circadian alignment.
- Late-day naps delay the rhythm.
- Evening bright light and screens delay the rhythm.
- Weekend schedule shifts and travel misalign it.
- Meal timing and exercise timing also shift the rhythm.
References
Peer-reviewed sources supporting the key factors, contributing factors, and typical optimal range shown above.
- Duffy JF, Czeisler CA. Effect of light on human circadian physiology. Sleep Medicine Clinics. 2009;4(2):165–177. doi.org/10.1016/j.jsmc.2009.01.004
- Wittmann M, Dinich J, Merrow M, Roenneberg T. Social jetlag: misalignment of biological and social time. Chronobiology International. 2006;23(1–2):497–509. doi.org/10.1080/07420520500545979
- Boivin DB, Boudreau P, Kosmadopoulos A. Disturbance of the circadian system in shift work and its health impact. Journal of Biological Rhythms. 2022;37(1):3–28. doi.org/10.1177/07487304211064218
- Roenneberg T, Kuehnle T, Juda M, et al.. Epidemiology of the human circadian clock. Sleep Medicine Reviews. 2007;11(6):429–438. doi.org/10.1016/j.smrv.2007.07.005
This guide is general information, not medical advice. Talk to your clinician about your own results.