Researchers at the University of Oulu in Finland found that an irregular sleep schedule is associated with a higher risk of heart disease [1, 2].
Maintaining a consistent sleep-wake cycle is critical because disruptions to circadian rhythms can impair cardiovascular regulation. This research highlights that the timing of sleep may be as important as the total amount of rest a person receives.
The study, published in 2023, indicates that an irregular sleep schedule may double the risk of serious heart problems [1]. Specifically, the risk of suffering a heart attack or stroke can double for individuals who maintain irregular bedtimes and sleep fewer than eight hours per night [2, 3].
While some data suggests the risk is most acute when combined with short sleep duration, other reports indicate that irregular sleep patterns alone may increase heart disease risk regardless of total hours slept [1, 2]. Conversely, establishing a consistent bedtime could lower the risk of heart disease by up to 50% [4].
The findings are based on data collected from participants in the University of Oulu cohort. The researchers said that inconsistent sleep timing disrupts the body's internal clock, which manages blood pressure and heart rate throughout the day and night [1, 4].
Medical professionals generally recommend a stable sleep routine to support long-term cardiovascular health. This includes going to bed and waking up at the same time every day, including weekends, to minimize the stress placed on the heart [4].
“An irregular sleep schedule may double the risk of serious heart problems”
This research shifts the focus of sleep health from quantity to consistency. While public health guidance often emphasizes the need for seven to eight hours of sleep, these findings suggest that 'social jet lag'—the discrepancy between a biological clock and a social schedule—creates a physiological strain on the heart that cannot be fully mitigated by total sleep volume alone.
