Chronotype is an individual characteristic of circadian rhythms. Some experts call this an “internal clock” that helps determine when to fall asleep and when to stay awake. The authors of the new study note that previous work has focused only on morning and evening chronotypes, but scientists have suggested that there may be more. So, in the course of the study, the authors were able to expand the classification of daily activity to 6 types: morning (larks), evening (owls), highly active type, daytime sleepy type, daytime active type and moderately active type. Morning chronotypes have more energy early in the day, which drops to medium levels in the afternoon and then to low levels in the evening. In contrast, evening chronotypes exhibit a low level of vigor in the morning, which rises to an average level in the middle of the day and then rises to a high level at night. To confirm the new classification, Dmitry Sveshnikov, assistant professor of normal physiology at the RUDN Medical Institute, and his colleagues interviewed nearly 2,300 participants, most of whom were students. The volunteers were asked to independently assess their chronotype based on a series of six possible ones. Participants performed a series of standard tests used by scientists to assess a person's level of sleepiness or alertness at different times of the day. As a result, the scientists found that the vast majority of the participants were able to identify with one of the six chronotypes suggested by the researchers. Only 5% of the respondents could not attribute themselves to any type of wakefulness. 13% of people classified themselves as "classic" larks, 24% - as owls. In general, scientists note that people are more likely to identify with evening types. 18% of participants said that they feel constantly sleepy during the daytime (daytime sleepy type), 16% were moderately active during the day (moderately active type), 15% noted that, on the contrary, they feel a surge of energy during the day (daytime active type) and only 9% said they were very active all day long (highly active type).
