If you regularly wake up and go to bed at different times, you can increase your risk of heart attack and stroke.
Sleep regularity, or how often you stick to the same sleep-wake schedule, appears to be a stronger predictor of major cardiovascular events than sleep duration, according to new research in the journal Health.
This is the first study of its kind to look at the effects of both sleep duration and sleep regularity on heart disease.
The authors found that the risk of heart attack, stroke and heart failure was significantly increased in all people with sleep disturbances, even if they got the recommended number of hours of sleep for their age.
In contrast, people who strictly adhere to regular sleep and wake schedules have a lower risk of cardiovascular disease.
“Sleep irregularity refers to frequent changes in sleep patterns, such as going to bed and waking up at different times each day, which can disrupt the body and negatively impact health. This research is public health. guidelines and emphasize the importance of prioritizing sleep in medical care to support cardiovascular health, the researcher said.
Increased risk of cardiovascular events in irregular sleepers
The large study included more than 72,000 people aged 40 to 79 who had no history of cardiovascular events.
All participants were part of the UK Biobank cohort, a biomedical database containing de-identified data from half a million people in the UK.
Sleep is complex, so the researchers tried to control for various factors that could affect the study’s results, including age, gender, race, history of heart disease, and mental health. They also included important lifestyle factors that may affect sleep quality, such as self-reported sleep problems, whether or not the individual worked odd hours (night shifts), and even That screen time.
Another strength of the study is that it did not rely on self-reported sleep data. Participants used activity trackers to record their sleep for seven days.
Based on the recorded sleep data, participants were given a “Sleep Regularity Index” (SRI) score. Low scores indicate sleep disturbances. Individuals in the cohort were further divided into three groups according to their SRI scores:
regular: An SRI of over 87.3
Moderate to irregular: SRI of 71.6 to 87.3
Irregular: An SRI of less than 71.6
The study found that irregular sleepers had a 26 percent increased risk of cardiovascular disease, and moderate sleepers had a modest 8 percent increase.
The next question for the researchers was whether not getting enough sleep could reduce the risk of irregular sleep patterns.
Unfortunately, they found that even getting the recommended number of hours was not enough to reduce the risk of irregular sleepers, but it did have an effect on those in the moderately irregular group.
“Although adequate sleep duration and sleep routines are both important, our findings suggest that meeting sleep duration recommendations alone does not eliminate the increased risk of MACE for these individuals,” the researcher said. Whose sleep patterns are irregular.”
In fact, regular sleep patterns were actually found to be protective against cardiovascular outcomes.
A minimum SRI score of 77.1 was associated with a 15% reduction in risk, with an even greater benefit associated with more regular sleep: an 18% reduction from an SRI of 80.8.
Risks of irregular sleep-wake cycles
Although research has focused on sleep duration, sleep regularity has been linked to many negative health outcomes.
A 2023 study published in Sleep found that sleep regularity was a stronger predictor of overall mortality risk than sleep duration. Participants with the highest SRI scores had a 48% lower risk of all-cause mortality than those with the lowest SRI scores.
Andrew JK Phillips, MD, a sleep scientist and associate professor at Flinders University College of Medicine and Public Health, was the senior author of the study.
He said this new research on cardiovascular outcomes is consistent with his own research.
“There’s a strong emerging body of evidence, not just from my group but from many research groups around the world, that shows that irregular sleep patterns are bad for our health,” Phillips said. “It’s that sleep regularity is not just a predictor of one area of health, but appears to touch a wide range of health outcomes, from mortality to diabetes to mental health,” Phillips said. .
Phillips also co-authored a 2017 study showing that irregular sleep is associated with poorer academic performance.
“Irregular sleep patterns likely disrupt the body’s network of circadian (24-hour) clocks. These clocks regulate the timing of all kinds of physiological functions throughout the body, including cell metabolism,” he said. said