Sleep and Dreaming The Grownup's Sleep Guide The Grownup's Sleep Guide World Sleep Strategies Sleeping Positions Bedtime Procrastination Identifying Your Chronotype Obstructive Sleep Apnea Sleep Hygiene Sleep Debt How Your Chronotype Affects Your Quality of Sleep By Cynthia Vinney, PhD Cynthia Vinney, PhD Cynthia Vinney, PhD is an expert in media psychology and a published scholar whose work has been published in peer-reviewed psychology journals. Learn about our editorial process Updated on March 01, 2023 Medically reviewed Verywell Mind articles are reviewed by board-certified physicians and mental healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Shaheen Lakhan, MD, PhD, FAAN Medically reviewed by Shaheen Lakhan, MD, PhD, FAAN Shaheen Lakhan, MD, PhD, is an award-winning physician-scientist and clinical development specialist. Learn about our Medical Review Board Print Maria Korneeva / Getty Images Table of Contents View All Table of Contents What Is a Chronotype? Chronotype Categories Discovering Your Chronotype Why Do People Have Different Chronotypes? How Do Chronotypes Affect Sleep? Next in The Grownup's Sleep Guide Obstructive Sleep Apnea and Its Effect on Mental Health If you’ve ever referred to yourself as a “morning person” or a “night person,” you were referencing your chronotype. It is a natural individual difference that can have a big impact on how much and how well you sleep, especially if you have a job or other obligations that adhere to a schedule that doesn't work with your chronotype. This article will define what a chronotype is, detail the categories of chronotypes, and explain why chronotypes differ between people. It will then wrap up with a discussion of chronotypes’ impact on sleep. What Is a Chronotype? Chronotypes are an individual’s natural predisposition to sleep and wake up at certain times of day. Chronotype also influences how alert or tired you feel at various times throughout the day and impacts when you’ll be most productive during your waking hours. Chronotype is related to circadian rhythm. Circadian rhythm coordinates your body’s physiological processes, including the sleep-wake cycle, into a 24-hour sequence. Your chronotype, also known as a circadian preference or circadian typology, is your innate inclination to sleep or wake up based on your circadian rhythm. Chronotype isn’t the same thing as sleep duration, which is the total number of hours you sleep a night, but chronotype may influence sleep duration. For example, someone who has to get up at 7:30 a.m. for work is likely to get more sleep if they’re a morning person than if they’re a night person. Research has shown that chronotype changes throughout the lifecycle. Kindergarten children prefer to wake up early, while adolescents prefer waking up and going to sleep later in the day, a phenomenon that increases throughout the teen years and peaks around the age of 19. Chronotype then shifts back to a preference for waking up earlier throughout adulthood. Men generally have later chronotypes than women before the age of 40, but after age 40 have earlier chronotypes. Chronotype Categories Researchers have divided chronotype into three categories: Morningness, or the preference for waking up and going to bed earlier than most people.Eveningness, or the preference for waking up and going to bed later than most people.Intermediate, which falls somewhere in between morningness and eveningness. Even though both sleep scholars and the general population tend to emphasize morningness and eveningness when describing sleep timing preferences, the reality is that chronotypes are distributed nearly evenly along a spectrum. As a result, most people fall somewhere between the extremes of morningness and eveningness. Furthermore, a number of scholars have suggested there's a fourth chronotype: Bimodal, or people who display some aspects of morningness and some aspects of eveningness. Early Risers at Lower Risk of Developing Depression, Study Suggests Discovering Your Chronotype You may already know you wake up before the sun rises or prefer to go to bed after most everyone else is asleep, but if you're not sure what chronotype category you fit into and want to find out, you can take the Morningness-Eveningness Questionnaire. This is the measure most often used by scientists. It is available either online with automated results that come with personalized feedback or in a printable format that explains how to interpret the results for yourself. One of the most popular chronotype assessments is the chronotype quiz by clinical psychologist and sleep expert Michael Breus, who has broken chronotype down into four categories based on animals, including: Lion — which roughly correlates to morningnessWolf — which roughly correlates to eveningnessBear — which roughly correlates to intermediate types. According to Breus, this type is more productive before noon and decreases in energy in the late afternoon.Dolphin — which roughly correlates to bimodal types. Breus says these individuals are most productive between 10 a.m. and 2 p.m. While Breus’ quiz is fun and easy to take, it’s important to know that there's no evidence to suggest it has been validated or peer-reviewed, the gold standards for confirming that a questionnaire actually measures what it claims to. Why Do People Have Different Chronotypes? Some scholars propose that the variations in chronotype between individuals is a product of human evolution. A 2017 investigation of a hunter-gatherer tribe in Tanzania demonstrated that over 20 days, different individuals took turns sleeping while others were awake. This asynchronous sleep-wake pattern was connected to variations in chronotype. Based on these findings, the researchers suggested that different chronotypes are a product of natural selection, ensuring certain people stayed awake to keep watch at various times throughout the night to protect the group against vulnerabilities to predators and other dangers during sleep. How Do Chronotypes Affect Sleep? Adequate sleep is essential for healthy functioning. Therefore, it’s valuable to know how our chronotype might impact our sleep. Chronotype can effect how individuals interact with their environment, especially when it comes to the social parameters of work and school hours or other scheduled activities. This can be especially problematic for people with an evening chronotype. Later chronotypes have a tendency to get the least sleep, be chronically tired, and suffer from disturbances during sleep. They also experience the most social jetlag, or the shifts people make in their sleep schedule between the work week and the weekend due to a mismatch between their innate chronotype and the demands of their weekday schedule. A single hour of social jetlag can increase cardiovascular disease risk by 11%, so evening types' predilection toward social jetlag not only disrupts their sleep schedule, but it can also impact their overall health. In addition, those with later chronotypes have a tendency to have poorer sleep quality. Meanwhile, those with morning chronotypes appear to adjust more quickly to shifts in the duration, timing, and quality of their sleep than evening chronotypes. On the other hand, morning chronotypes may have difficulty staying up late to participate in social activities. While an individual’s chronotype is likely to vary throughout their lifetime, it can’t be changed to accommodate work or school schedules. As a result, adolescents and others with an evening chronotype are at a particular disadvantage because their chronotype doesn’t align with the expectations of early school and work schedules. This is why experts have pushed for later school start times for middle and high school students. Irregular Sleep Schedules May Be as Bad as Getting Too Little Sleep A Word From Verywell If you have a later chronotype and work at an office that adheres to an earlier schedule, it might be beneficial to speak to your boss about your particular needs. Morning chronotypes will thrive on a standard office-day work schedule, but evening chronotypes are likely to be more productive if they start and end their workday later. In fact, one study found that evening chronotypes who worked from home during the COVID-19 pandemic and therefore had the flexibility to get up and go to bed later in the day no longer experienced issues with sleep. This indicates that if evening types were able to work on a schedule that lined up with their chronotype, their sleep quality and quantity would improve. 9 Sources Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Randler C, Schredl M, Göritz AS. Chronotype, sleep behavior, and the big five personality factors. SAGE Open. 2017;7(3). doi:10.1177/2158244017728321 Tempaku PF, Ramirez Arruda J, Mazzotti DR, et al. 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Later school start times more popular, but what are the drawbacks? National Education Association. 2022. Salfi F, D’Atri A, Amicucci G, et al. The fall of vulnerability to sleep disturbances in evening chronotypes when working from home and its implications for depression. Sci Rep. 2022;12(1):12249. doi:10.1038/s41598-022-16256-6 By Cynthia Vinney, PhD Cynthia Vinney, PhD is an expert in media psychology and a published scholar whose work has been published in peer-reviewed psychology journals. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit Speak to a Therapist Online Advertiser Disclosure × The offers that appear in this table are from partnerships from which Verywell Mind receives compensation.