SUFFICIENT SLEEP HAS been proven to help keep the body healthy and the mind sharp – but it’s not just an issue of logging at least seven hours of shut-eye a night. 

A new study in the US on sleep patterns has suggested that a regular bedtime and wake time are just as important for heart and metabolic health among older adults. 

In a study of 1,978 older adults, researchers at Duke Health and the Duke Clinical Research Institute found that 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 connected to heart health. 

The data showed that African-Americans had the most irregular sleep patterns compared to participants who were white, Chinese-American or Hispanic. 

The findings also found an association – not a cause-and-effect relationship – 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 Lundsford-Avery, the study’s lead author. 

“Perhaps all of these things are impacting each other.” 

The data does still, however, suggest that 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 United States, are extremely costly and are also are leading causes of death in this country,” she said.

“To the extent, we can predict individuals at risk for these diseases, we may be able to prevent or delay their onset.”

The study

The participants used devices that tracked sleep schedules down to the minute so researchers could learn whether even subtle changes, such as going to bed at 10.10pm instead of the usual 10pm, where linked to their health. 

Their ages ranged from 54 to 93, and 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, such as 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. 

As one may 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 said. 

“Or, as some researchers suggest, perhaps poor sleep interferes with the body’s metabolism which can lead to weight gain, and it’s a vicious cycle,” she said. 

“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.”