WASHINGTON: New research indicates that inconsistent sleep patterns—such as going to bed and waking up at varying times—could raise the risk of heart attacks and strokes, even for those who meet the recommended sleep duration.
While previous studies have primarily focused on how long people sleep and its effects on health, this study delved into how fluctuations in the sleep cycle might influence cardiovascular health. The study followed 72,269 participants aged 40 to 79 who had no history of major heart or stroke events. For seven days, scientists tracked their sleep behavior and calculated a “Sleep Regularity Index” (SRI), with higher scores indicating more regular sleep routines.
Over eight years, researchers monitored these participants for any instances of heart attacks, strokes, heart failure, or cardiovascular death. The results showed that those with irregular sleep patterns had a 26% higher likelihood of experiencing a major cardiovascular event compared to those who maintained a more consistent sleep schedule. This figure accounted for other factors like age, activity levels, alcohol use, and smoking, but the study did not prove causation, only a correlation.
Notably, individuals with higher SRI scores (meaning they had more regular sleep) were more likely to get the recommended 7 to 9 hours of sleep each night, which is advised for people aged 18 to 64, or 7 to 8 hours for those over 65. About 61% of people with regular sleep cycles met the sleep guidelines, while only 48% of those with irregular sleep patterns did.
The study also found that even among those who got the recommended amount of sleep but had irregular patterns, the risk of heart attacks and strokes remained higher. The findings suggest that keeping a regular sleep schedule may be more crucial for heart health than simply getting enough sleep.
Lead author Jean Pierre Chaput, a professor at the University of Ottawa, explained that “sleep irregularity may be a more significant predictor of cardiovascular risk than inadequate sleep.” He also noted that high blood pressure is a key factor contributing to cardiovascular problems and recommended prioritizing consistent, high-quality sleep of 7 to 9 hours each night.
Chaput further advised keeping bedtimes and wake-up times within 30 to 60 minutes of each other to align with the body’s natural circadian rhythm. While slight variations in sleep times are acceptable, maintaining a regular routine can enhance sleep quality, improve mood and cognitive function, and lower the likelihood of developing heart disease, diabetes, and other chronic conditions.
Additionally, Chaput warned against relying on weekend sleep to compensate for a lack of sleep during the week, stating that while extra sleep on weekends can temporarily boost mood, it doesn’t fully offset the long-term effects of poor sleep during the workweek.
Although the study points to a link between irregular sleep patterns and cardiovascular risks, experts such as Naveed Sattar, a professor at the University of Glasgow, caution that other lifestyle factors may also play a role in the health outcomes observed. Therefore, more research is needed to understand the full implications of these findings.
The review was distributed in the Journal of Epidemiology & Community Health.
