It’s not just a lack of enough sleep that affects a person’s health, suggests a new study. According to recent evidence, having irregular sleeping patterns may lead to a risk of cardiovascular problems.
Researchers already know that sleep is important to wellbeing. Studies has shown that almost every aspect of health is impaired without a sufficient sleep, from cognitive functioning to immunity.
But even people who sleep for a good number of hours each night can face increased health risks if their sleep is erratic— that is, if the hours they sleep vary wildly from night to night, or if their bedtime and wake-up times change a great deal.
A new study conducted by Brigham and Women’s Hospital researchers in Boston, MA, has found that people with very irregular sleep cycles are more likely to experience cardiovascular events than those with more regular sleep.
Authors of the study report their findings in the American College of Cardiology Journal and emphasize the importance of good hygiene for the sleep.
“When we think about heart attack and stroke prevention strategies, we’re focused on diet and exercise,” remarks lead author Tianyi Huang.
He continues, “Even when we talk about sleep, we tend to focus on length— how many hours a person sleeps every night— but not on sleep disturbances and the effect of going to bed at different times, or sleeping in different amounts from night to night.”
“Our study indicates that healthy sleep isn’t just about quantity but also about variability and that this can have an important effect on heart health.”
– Tianyi Huang.
The researchers analyzed data from 1,992 older participants in their 60s and 70s, without underlying cardiovascular issues.
The participants were of different ethnicities, including African Americans and Chinese Americans, with all the data coming from the Atherosclerosis Multi-Ethnic study .
The team was able to chart the sleeping patterns of the participants, as they each chose to wear an actigraph unit— an activity tracking device worn on the wrist— over a 7-day period.
This allowed researchers to obtain information on bedtime, sleep durations, and wake-up times for the participants.
The researchers also had access to health survey information, covering an average 4.9-year duration.
A total of 111 participants have undergone numerous cardiovascular events over that time, such as heart attacks and strokes.
The research team noticed that participants with the most irregular sleep patterns— those with 2 hours or more difference in sleep duration every night — had more than double the risk of cardiovascular problems relative to those with 1 hour or less difference in sleep duration.
Even after accounting for other cardiovascular risk factors, the authors saw that the link between irregular sleep patterns and cardiovascular events remained significant.
“Although we also found that participants with irregular sleep tended to have worse cardiometabolic risk profiles at baseline, adjustment for known risk factors (e.g. blood pressure, lipids, diabetes, etc.) only clarified a small portion of the associations between sleep irregularity and risk of[ cardiovascular disease],” they wrote in their study report.
The new research, however, was not without its limitations. The authors note that the population to which they had exposure was relatively small, and the follow-up duration was not quite long enough to make the relation between cardiovascular risk and sleep habits unquestionable.
The team states, however, that more work will confirm their results, they would be interested in figuring out whether modifying the sleep habits of an individual could reduce their risk of heart and vascular problems.
“The regularity of sleep is a modifiable trait. In the future, we’d like to explore how improving one’s sleep patterns by regularly going to bed every night will reduce a person’s risk of future cardiovascular events,” says Huang.