Written by Lisa Meltzer, the Sleep Science Advisor at Zepp Aura
1. What is a Chronotype?
Your chronotype is when your body naturally wants to be awake or asleep at certain times. Unfortunately, this might not align with when society expects you to sleep, but more on that in a moment.
Morning Types, Evening Types, and the Rest
Morning Types are people who like to wake up early and go to bed early. About 20–30% of the population are morning types.
Evening Types are people who like to go to bed late and wake up late, and are most alert in the late afternoon and evening. About 20–30% of the population are evening types.
The rest of the population are considered Intermediate Types, and do not have a strong biological preference for bedtimes and wake times.
Your chronotype is determined by:
- Genetics — Chronotypes run in families, so if you have one or two parents who are evening types or morning types, you are more likely to be one of them.
- Age — During puberty and adolescence, chronotypes shift later, peaking around the age of 19 years, and then shifting earlier over the rest of the lifespan.
- Environmental factors — Our biological circadian rhythm (or internal clock) is heavily influenced by light and dark. Chronotype is also impacted by light exposure, so it is not surprising that earlier chronotypes are more likely to live in rural areas where people work outside and are exposed to a lot of morning light. Similarly, areas that do not have electricity are exposed to less evening light, which can delay sleep onset and push chronotypes later.
2. Why Does Knowing Your Chronotype Matter?
Your chronotype may have a significant impact on sleep, health, peak alertness, and daytime functioning. If possible, it is important to try and adapt your lifestyle to your chronotype.
Different societies have certain expectations of when people will be awake, typically reflected in required workday hours or school start times. Most societies favor morning types, with early morning start times for work or school. This can be highly problematic for evening types, whose alertness and peak performance occurs in the afternoon and evening.
Because they have to wake early in the morning for work or school, but have difficulty falling asleep early at night, evening types often do not get enough sleep.
Notably, on weekends or holidays, evening types are able to get as much, if not more, sleep than morning types. However, this increased weekend sleep duration results from the opportunity to shift bedtimes and wake times later in order to align with their biological rhythm.
Downstream health effects of not getting enough sleep have been found in evening types, including higher rates of hypertension, impaired insulin functioning, higher BMI, and more depression.
When possible, evening types will benefit from adjusting their work schedules, with a later start and end time. This will not only increase their opportunity to get more sleep, but will also align their work performance with peak alertness during the day.
Evening types and morning types may also benefit from exercising at different times of the day. Morning types have been found to perceive less exertion if they exercise in the morning, while evening types perceive greater fatigue with morning exercise. Similarly, athletic performance is better in the morning for morning types. Evening types, on the other hand, need more time to prepare for sports activities than morning types, so it is also important to consider how long a person has been awake prior to engaging in activities.
3. What is Your Chronotype?
Here is a quick way to think about your chronotype: If you were able to choose your sleep schedule, with no obligations or people telling you what you need to do, when would you ideally go to bed and wake up?
Does your answer align with your current daily schedule? If not, that may be one reason you feel tired, have difficulties falling asleep or waking up, or need more caffeine during the day.
Although your chronotype is based on your biological sleep rhythms, this questionnaire asks about your preference and feelings of alertness. It will provide you with feedback about your circadian preference.
