Chronotype quiz

What is a chronotype?

A chronotype is where your body clock sits in the 24-hour day. This chronotype quiz, a short circadian rhythm test, measures it the way the Munich ChronoType Questionnaire (MCTQ) does: the midpoint of your sleep on free days, corrected for the extra sleep you catch up on after a short-slept week. A later midpoint means a later chronotype.²

It is a scale, not a set of boxes. The MCTQ team describes chronotype as continuous and closer to a state than a fixed trait.² More time in daylight goes with earlier sleep, and chronotype differs by age and sex.¹³ On average it gets later from about age 10, is latest around 20 and moves earlier for the rest of life.²

How this chronotype quiz works

From your four times it works out sleep length and mid-sleep for workdays and free days. Times past midnight are handled, so falling asleep at 1 AM and waking at 9 AM counts as 8 hours with mid-sleep at 5 AM.

• MSF and MSW: sleep onset plus half your sleep length, on free days and workdays.
• Weekly average sleep: (workday sleep × workdays + free-day sleep × free days) ÷ 7.⁴
• MSFsc: if you sleep longer on free days than on workdays, MSF minus half the difference between free-day sleep and your weekly average. Otherwise MSFsc equals MSF.²
• Social jetlag: the gap between MSF and MSW.²⁵

The correction matters because most people pay back weekday sleep debt by sleeping in, not by going to bed earlier. Late types can sleep several hours longer on free days.¹ Without the correction, anyone short of sleep during the week would score later than their clock really is.²

How the seven chronotype bands are set

There is no official cut-off table. Studies often split MSFsc by their own sample's quantiles.⁶ We use the seven groups from the MCTQ database chart of 185,333 people, read off its half-hour bins. The chart does not print exact cut-offs, so each edge could be off by about 15 minutes.²

Why lion, bear, wolf and dolphin types are not here

The four animal chronotypes come from The Power of When, a 2016 popular book by Michael Breus, not from chronotype research. Sleep researchers measure chronotype on a continuous clock-time scale, which is what this quiz reports.²

What the result can and can't tell you

• Alarms on free days break it. The MCTQ only scores chronotype when people wake without an alarm on free days. In one validation sample, 22.5% used one and could not be scored.⁶
• It is a short version. The full MCTQ also asks about time in bed, time to fall asleep and time outdoors. This quiz takes sleep onset and wake time directly.
• It is reasonably accurate. In 80 adults in Portugal, questionnaire MSFsc correlated with four weeks of actimetry at rho 0.65, and a repeat in 30 of them gave rho 0.91.⁶
• Shift work needs a different version. Work shifts distort sleep timing, so the MCTQ team built a separate shift-work questionnaire.² See sleep timing for shift workers.
• Use typical weeks. Skip weeks with travel, illness or the clocks changing.

Light is the main signal that sets the clock. Light before the low point of your body temperature rhythm, which falls during the night, pushes the clock later. Light after that low point pulls it earlier.⁷ In a three-week randomized trial, late types who woke earlier, got morning light and kept regular meals shifted their sleep and melatonin timing about 2 hours earlier (n=22).⁸ Higher social jetlag has been linked with higher BMI in a large survey, which is a reason to keep weekend wake times close to weekday ones.⁹ For a step-by-step plan, read morning sunlight and your body clock or how to fix your sleep schedule. If you have bipolar disorder, ask your doctor before using a light therapy lamp.

Sources

1. Roenneberg T, Wirz-Justice A, Merrow M. Life between clocks: daily temporal patterns of human chronotypes. J Biol Rhythms. 2003;18(1):80–90. doi:10.1177/0748730402239679
2. Roenneberg T, Pilz LK, Zerbini G, Winnebeck EC. Chronotype and social jetlag: a (self-) critical review. Biology (Basel). 2019;8(3):54. doi:10.3390/biology8030054
3. Roenneberg T, Kuehnle T, Juda M, et al. Epidemiology of the human circadian clock. Sleep Med Rev. 2007;11:429–438. doi:10.1016/j.smrv.2007.07.005
4. rOpenSci mctq package. Compute MCTQ average weekly sleep duration (sd_week). docs.ropensci.org/mctq
5. Wittmann M, Dinich J, Merrow M, Roenneberg T. Social jetlag: misalignment of biological and social time. Chronobiol Int. 2006;23:497–509. doi:10.1080/07420520500545979
6. Reis C, Madeira SG, Lopes LV, Paiva T, Roenneberg T. Validation of the Portuguese variant of the Munich Chronotype Questionnaire (MCTQ^PT). Front Physiol. 2020;11:795. doi:10.3389/fphys.2020.00795
7. Khalsa SB, Jewett ME, Cajochen C, Czeisler CA. A phase response curve to single bright light pulses in human subjects. J Physiol. 2003;549(Pt 3):945–952. doi:10.1113/jphysiol.2003.040477
8. Facer-Childs ER, Middleton B, Skene DJ, Bagshaw AP. Resetting the late timing of 'night owls' has a positive impact on mental health and performance. Sleep Med. 2019;60:236–247. doi:10.1016/j.sleep.2019.05.001
9. Roenneberg T, Allebrandt KV, Merrow M, Vetter C. Social jetlag and obesity. Curr Biol. 2012;22(10):939–943. doi:10.1016/j.cub.2012.03.038

General information, not medical advice. If you can't fall asleep or wake at the times your life needs despite a regular schedule, talk to a doctor.