Study: Sleep Irregularities Increase Risk of Heart Attacks and Strokes

30th November 2024

3 minutes read

Study: Sleep Irregularities Increase Risk of Heart Attacks and Strokes

Irregular sleep and wake times are linked to an increased risk of heart attacks and strokes, even among individuals who get the recommended amount of sleep, according to a new study.

The study revealed that irregular sleep patterns may raise these risks.

While most previous research has focused on the impact of sleep duration on health, little is known about the effects of fluctuations in sleep cycles, researchers noted in a statement.

To address this issue, scientists tracked activity data from 72,269 participants aged 40 to 79 years over seven days. None of these participants had previously experienced a major cardiovascular event.

They calculated each individual’s Sleep Regularity Index (SRI), where higher scores indicated more regular sleep patterns.

The team then tracked deaths caused by cardiovascular diseases, heart attacks, heart failure, and strokes over an eight-year period. They found that individuals with irregular sleep cycles were 26% more likely to experience one of these events compared to those with regular sleep cycles. Irregular sleep was defined as variations in bedtime and wake-up times.

The 26% increased risk accounted for various factors, including age, physical activity, alcohol consumption, and smoking, which might have influenced the results. However, as this was an observational study, it could only establish a correlation rather than a cause-and-effect relationship. It remains uncertain whether irregular sleep patterns directly increase these risks.

Researchers also noted that individuals with higher SRI scores (more regular sleep) were more likely to achieve the recommended 7–9 hours of sleep per night for ages 18–64 and 7–8 hours for those over 65. Among regular sleepers, 61% met these recommendations, compared to only 48% of irregular sleepers.

Nevertheless, even irregular sleepers who achieved the recommended sleep duration were still at greater risk of major cardiovascular events.

The study concluded, “Our findings suggest that sleep regularity may be more important than adequate sleep duration.”

The Role of Sleep Deprivation

Jean-Pierre Chaput, the study’s lead author and a professor of pediatrics at the University of Ottawa, Canada, told CNN, “A growing body of research suggests that irregular sleep may be a stronger predictor of mortality risk than sleep deprivation.”

Regarding reducing cardiovascular risks, Chaput emphasized that hypertension is a key risk factor.

He also cautioned against relying on weekend sleep compensation.

Sleep Cycle Impacts

Chaput, who is currently collaborating with the World Health Organization to develop sleep health guidelines, added, “While extra sleep on weekends can temporarily improve mood and cognitive function, irregular sleep cycles can disrupt your body’s circadian rhythm and lead to long-term health risks such as obesity, diabetes, and cardiovascular diseases.”

He continued, “I believe the next critical step is ensuring that sleep is valued as a fundamental pillar of well-being, rather than being dismissed as a waste of time in our society.”

Navid Sattar, a professor of cardiovascular medicine at the University of Glasgow, Scotland, who was not involved in the research, stated that while there is a link between sleep cycles and cardiovascular health, the study used “overly causal language.”

Sattar explained that other factors, such as late-night alcohol consumption, might account for the adverse outcomes rather than the sleep cycle itself.