According to a new US study, people who have a habit of getting up early would have 12 to 27% less risk of developing depression. Explanations.
What if we sleep early and get up early in the morning rather than sleep late is a key factor in our mental well-being and psychic health?
This is the result of new work by researchers at Boulder University, Colorado, and the Channing Division of Network Medicine at Boston's Brigham and Women's Hospital. In a new study published in the Journal of Psychiatric Research, they say early-risers are much less likely to suffer from depression.
The Nurses Health Study II
Unpublished by its size, this vast observational study explores the link between "chronotype", that is to say our rhythm of life, and mood disorders. It covers the data of more than 32,000 participants, on average 55 years old, all nurses, the famous "Nurses Health Study II", a cohort of follow-up in time as the Framingham study, but only on women . None was suffering from depression in 2009, when the study began.
Participants were asked about their sleep habits: 37% described themselves as preferring in the morning, 53% in the middle of the day and 10% in the evening. The women were then followed for 4 years to analyze the development of a possible depression.
A risk of depression lower from 12% to 27%
Researchers have found that late chronotypes, that is, "night birds", are less likely to be married, are more likely to live alone and to be smokers, and tend to have erratic sleep habits.
They also noted that early risers still had a 12- to 27-percent lower risk of depression than intermediate types. Late types, they were at risk 6% higher than the intermediate types.
"This tells us that there may be a direct effect of the chronotype on the risk of depression, an effect that is not motivated by environmental and lifestyle factors," explains Celine Vetter, lead author of the study. and director of CU Boulder's Circadian and Sleep Epidemiology Laboratory (CASEL).
Results to qualify
Previous work has shown that genetics play a key role in our sleep preferences. The hereditary character of depressive disorders is also to be considered, as is the role played by certain environmental factors such as exposure to light and working hours.
The results of the study are therefore to be clarified, as pointed out by Dr. Céline Vetter. "The timing and amount of light you obtain also influences the chronotype, and exposure to light also influences the risk of depression." Unraveling the contribution of light patterns and genetics to the link between chronotype and risk depression is an important next step, "she explains.
An effect that remains modest
But do not worry if you have a habit of going to bed in the early morning and not getting up until the afternoon: all the night owls are not destined to make a depression, say the researchers. "Yes, the chronotype is relevant when it comes to depression, but it's a small effect," says Céline Vetter, who still recommends that the night owl "get enough sleep, exercise, spend time outside, darken the lights at night and enjoy the light of day. "