Getting enough Z’s at night has been known to have beneficial effects on the body. But, it might not be just about making sure you get the normal amount of hours in for the night.
A new study on sleep patterns from researchers at Duke University Health and the Duke Clinical Research Institute suggests that a keeping your bedtime and wake time regular are just as important for heart and metabolic health, especially for older adults.
The study, which involved 1,978 older adults, found people with irregular sleep patterns weighed more, had higher blood sugar, higher blood pressure, and a higher projected risk of having a heart attack or stroke within 10 years than those who slept and woke at the same times every day.
Irregular sleepers were also more likely to report depression and stress than regular sleepers, both of which are tied to heart health, according to a press release.
Researchers also found African-Americans had the most irregular sleep patterns compared to participants who were white, Chinese-American or Hispanic, based on the data collected.
“The findings show an association — not a cause-and-effect relationship — between sleep regularity and heart and metabolic health,” according to researchers.
“From our study, we can’t conclude that sleep irregularity results in health risks, or whether health conditions affect sleep,” says Dr. Jessica Lunsford-Avery, an assistant professor in psychiatry and behavioral sciences and the study’s lead author said in a statement.”Perhaps all of these things are impacting each other.”
Still, the data suggest tracking sleep regularity could help identify people at risk of disease, and where health disparities may impact specific groups, such as African Americans.
“Heart disease and diabetes are extremely common in the U.S. are extremely costly and also are leading causes of death in this country,” Lunsford-Avery adds. “To the extent that we can predict individuals at risk for these diseases, we may be able to prevent or delay their onset.”
How was the Study Conducted?
Participants in the study used devices that tracked sleep schedules very accurately so researchers could learn whether even small fluctuations in time were linked to the health of participants. Their ages ranged from 54 to 93. People with diagnosed sleep disorders such as sleep apnea were not included in the study.
The study also tracked the duration of participants’ sleep and preferred timing — whether someone turned in early or was a night owl. According to these measures, people with hypertension tended to sleep more hours, and people with obesity tended to stay up later.
Of all three measures, however, regularity was the best at predicting someone’s heart and metabolic disease risk, the researchers found.
As one might expect, irregular sleepers experienced more sleepiness during the day and were less active — perhaps because they were tired, Lunsford-Avery said.
Researchers plan to conduct more studies over longer periods in hopes of determining how biology causes changes in sleep regularity and vice-versa.
“Perhaps there’s something about obesity that disrupts sleep regularity,” Lunsford-Avery adds. “Or, as some research suggests, perhaps poor sleep interferes with the body’s metabolism which can lead to weight gain, and it’s a vicious cycle. With more research, 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.”
The research was published in the journal, Scientific Reports.