"Larks" get up at 6:00 and go to bed at 22:00, and the "owls" get up at 17:00 and fall asleep at 7-8 in the morning. In a recent study, scientists analyzed which types of people are most prone to depression. The results were published in the journal Nature.
How does a "chronotype" affect a person?
The sleep chronotype is the preferred time for activity and relaxation. The distribution of types of sleep is the same throughout the world: it follows a Gaussian curve with corresponding extremes on both sides. During puberty, the average value shifts toward later awakening. After puberty, a shift is observed towards an earlier awakening.
During the work week, owls accumulate a “feeling of sleep,” which “compensates” on weekends due to increased sleep.
Larks, on the other hand, sleep equally long during the work week and on weekends. Owls obviously live against their rhythm during working hours and get used to it badly.
Another study looked at the difference between sleep on vacation and after hours. There was also an additional difference between larks and owls: the former slept longer, both on vacation and outside. Whether this is due to a greater need for larks or for other reasons is not yet clear.
The difference between larks and owls is in each person’s internal clock. These internal clocks are found in almost every organism: they are genetically determined and unchanged.
The internal clock synchronizes the body's metabolic processes in each cell. In the framework of the so-called "chronotyping", scientists are trying to determine the corresponding individual body time by molecular analysis of cells.
What exists between chronotype and depression?
A study of 40,000 participants used health data from nurses. Researchers have focused on studying risk factors for women with chronic diseases. Analysis showed that the chronotype has a significant effect on the risk of depression.
According to the lead author of the study, the results indicate some connection between the chronotype and the risk of depression. To gain a better understanding of these relationships, the team analyzed data from 40,000 participants in a nursing health study.
Women were of all ages, the average age was 55 years old, and as of 2009 they were not depressed. 37% of the participants called themselves larks, 53% - intermediate, and 10% - owls. Then the women were monitored for 4 years, checking whether they had depression.
After taking into account factors that can contribute to depressive moods, analysts found that "night people" are more likely to live alone. Owls also smoked more often and had the wrong nature of sleep. Larks had a 12–27% lower risk of developing depression than those who considered themselves an intermediate type.
Does the risk of depression depend on genes?
Genetics plays a role in whether a person belongs to larks or owls. Some studies have shown that certain genes influence the preferred sleep-wake cycle and the risk of depression. However, genetics is not the only driving force behind depression.
According to scientists, daylight significantly reduces the risk of developing a bad mood.
Disclosing the role of light patterns and genetics in combining the chronotype with the risk of depression is an important next step in research.
Scientists note that the chronotype is a risk factor for depression. However, this does not mean that all owls are doomed to a bad mood. The chronotype must be taken into account when it comes to depression, but the factor itself has little effect on people.
If the daily schedule affects mental health, experts advise you to adjust it. If a person wants to get a good night's sleep, it is important to play sports and stay in the daylight for as long as possible. Simple but effective tips help in the natural maintenance of energy and mental health. In case of significant sleep disorders or depressive moods, it is recommended to seek the advice of a specialist.
