Sleep Pattern Analyzer
Enter your sleep schedule and discover your chronotype, visualize your sleep stages, calculate your social jet lag and find your peak performance windows.
The Three Human Chronotypes Explained
Chronotype — your biological preference for the timing of sleep and wakefulness — is primarily determined by your genetics. Professor Till Roenneberg at Ludwig Maximilian University in Munich, who coined the term social jet lag, has measured chronotypes in over 200,000 people across Europe. His data shows that human sleep timing follows a normal distribution, with most people falling in the intermediate range and smaller populations at either extreme.
Social Jet Lag — The Hidden Sleep Thief
Social jet lag is the difference between your biological sleep midpoint (when you naturally sleep without social constraints) and your social sleep midpoint (when you actually sleep). Professor Roenneberg's landmark research in 2012, published in Current Biology, found that 69% of the European population experiences at least one hour of social jet lag weekly — the equivalent of weekly transatlantic flights without leaving home.
The health consequences are significant and dose-dependent. Each hour of social jet lag is associated with a 33% increased odds of being overweight, elevated inflammatory markers, impaired insulin sensitivity, and reduced cognitive performance on standard tests. People with 2 or more hours of social jet lag show cognitive profiles similar to people sleeping 2 hours less than they actually do — a paradox that has confused researchers until chronobiology provided the explanation.
The mechanism is circadian misalignment: when you sleep at times that conflict with your internal biological clock, the synchronisation between your master clock in the suprachiasmatic nucleus and the peripheral clocks in your organs, immune system and metabolism breaks down. This desynchronisation impairs virtually every metabolic process that relies on circadian timing — which is most of them.
Frequently Asked Questions
Chronotype has a strong genetic component but can be shifted modestly through behavioural interventions. Morning bright light therapy (10,000 lux for 30 minutes immediately on waking) can advance an evening chronotype by 1–2 hours over 3–4 weeks. Strict wake time consistency matters more than bedtime for shifting phase. Age also shifts chronotype — it naturally advances (becomes earlier) from around age 20 onwards, accelerating after 50. You cannot completely change your chronotype but you can shift it by 1–2 hours with sustained effort.
A night owl chronotype is not inherently unhealthy — it is a natural biological variation. The health problems associated with evening chronotypes arise from the mismatch between biological timing and social obligations (work and school starting early), not from the chronotype itself. Research suggests that if society shifted to schedules aligned with natural chronotype diversity, health outcomes for evening types would improve substantially. The problem is social jet lag, not the chronotype.
The most clinically validated chronotype assessment is the Munich Chronotype Questionnaire (MCTQ) developed by Till Roenneberg, which asks specifically about sleep timing on free days without alarms. The Morningness-Eveningness Questionnaire (MEQ) by Horne and Östberg (1976) is also widely used. Both measure the same underlying construct. Our analyzer uses a simplified version of the MCTQ approach — comparing free-day sleep midpoint to social obligation sleep midpoint to calculate both chronotype and social jet lag simultaneously.