(CN) — A study published Friday in Scientific Reports suggests that a regular bedtime and wake time supports heart and metabolic health in older adults.
In a study of 1,978 older adults, researchers at Duke Health and the Duke Clinical Research Institute found that people who went to bed and woke up at roughly the same time every day had lower blood sugar, lower blood pressure and lesser risk of heart attack and stroke than those who slept on an irregular schedule.
Study participants ranged in age from 54 to 93 and used devices that tracked sleep schedules down to the minute. The study also tracked the duration of participants’ sleep and preferred timing. According to these measures, people with hypertension tended to sleep more hours, and people with obesity tended to stay up later.
Irregular sleepers were more likely to report depression and stress than regular sleepers. African-Americans had the most irregular sleep patterns compared to participants who were white, Chinese-American or Hispanic.
It’s already known that sleep is involved in healing and repair of the heart and blood vessels, and that ongoing sleep deficiency is linked to an increased risk of heart disease, kidney disease, high blood pressure, diabetes and stroke.
But the new study supported by the National Institute of Mental Health and the National Heart, Lung, and Blood Institute suggests there is also an association, though not a definitive causal effect, between sleep regularity and heart and metabolic health.
“From our study, we can’t conclude that sleep irregularity results in health risks, or whether health conditions affect sleep,” said Jessica Lunsford-Avery, Ph.D., an assistant professor in psychiatry and behavioral sciences and the study’s lead author. “Perhaps all of these things are impacting each other.”
Of the three metrics covered in the study: sleep duration, timing of sleep, and regularity of schedule, sleep regularity was best at predicting someone’s heart and metabolic disease risk, the researchers found.
Researchers plan to conduct more extensive studies over longer periods in hopes of determining how sleep regularity is linked to overall health.
“With more research,” Lunsford-Avery said, “we hope to understand what’s going on biologically, and perhaps then we could say what’s coming first or which is the chicken and which is the egg.”