When and how you sleep says a lot more about your overall health than you may know.
In fact, medical experts can use sleep patterns to gauge one’s risk for cognitive decline later in life, a range of psychological disorders, and even cardiovascular conditions.
The authors of a new report published in the Scandinavian Journal of Medicine & Science in Sports, elect chronotypes as a possible explanation.
“Morning, day or evening chronotypes differ by the circadian timing of alertness and the preferred timing of sleep. It has been suggested that evening chronotype is associated with low physical activity (PA) and high sedentary time (SED),” the authors wrote. “Our aim was to investigate whether such an association is confirmed by objectively measured PA and SED. In a 46‐year follow‐up of the Northern Finland Birth Cohort 1966 study, total PA and SED mong 5156 participants were determined using wrist‐worn accelerometers for 14 days.”
The most common chronotypes are as follows, indexed by Michael J. Breus, PhD, a clinical psychologist and fellow of the American Academy of Sleep Medicine.
The Lion (morning type): This type refers to early risers that rarely nap and are most alert at noon.
The Dolphin (night type): This group doesn’t have a time of day associated with optimal function, but the majority can be classified as insomniacs. They require a lot of sleep to function.
Of all the chronotypes featured in the new analysis, those belonging to the morning type were determined to be the most active.
More discreetly, male participants in this group enjoyed a median of 30 minutes more of walking each day compared to men belonging to the other two chronotypes. For women, the average disparity was consistent but was closer to a difference of 20 minutes.
These figures explain why morning types also evidenced better cardio health compared to the rest of the study pool.
“Evening chronotype was associated with low objectively measured PA in both sexes and with high SED in men, even after adjustments for established potential confounders. Chronotype should be considered in PA promotion,” the authors from the University of Oulu in Finland, continued.
Follow-up studies revealed that obesity, diabetes, and several serious metabolic conditions are more abundant among evening chronotypes.
The strength of the findings was not changed after the researchers controlled for people’s health, professions, socioeconomic status, and other factors.
“Our chronotypes can have a surprisingly important role in our lives,” Laura Nauha, a doctoral student at the University of Oulu told the New York Times. “Evening types may need to work harder to try to ensure they exercise.”
The mechanisms are multilayered. Although more research would need to be conducted to confirm, There may be physiological interactions between people’s body clocks, Nauha suspects that there might be biologic predispositions that cause evening chronotypes less able to be motivated to be active.
This distinction informs how we react to caffeine, process hormones, and the quality and depth of her sleep.
Ladders did a deep dive into chronotypes here.