Research from the Institute of Health and Welfare (THL) has highlighted the importance of a stable circadian rhythm in maintaining mental health in middle-aged adults. A ten-year study monitored the diurnal rhythm of individuals and found that those with an evening-oriented circadian rhythm experienced more instances of insufficient sleep, mental stress, and depressive symptoms. They also exhibited diurnal fatigue, indicating a shift in their sleep pattern between weekdays and weekends.
Interestingly, making a moderate adjustment to focus more on morning activities helped reduce psychological symptoms in individuals with an evening-oriented circadian rhythm. The study revealed that between the ages of 42 and 52, the individual circadian rhythm tends to remain fairly constant, with only subtle changes in morning and evening activity observed in most cases.
Surprisingly, less than one percent of participants reported a significant shift from a strong evening to a strong morning preference or vice versa. Conversely, around 60 percent noted no significant change in their circadian rhythm over the study period. The findings highlight the innate nature of the circadian rhythm and the rarity of major changes in this characteristic during middle age.
THL’s Visiting Researcher, Docent of Public Health Sciences Ilona Merikanto emphasized the importance of understanding the connection between circadian rhythm stability or changes and mental health. While this relationship has been minimally explored, the study sheds light on the significance of maintaining a consistent circadian rhythm for overall well-being in middle-aged individuals.
