Irregular bedtimes raise heart attack risk

Inconsistent sleep schedules may increase cardiovascular events

A study reported that large swings in when people go to bed are linked to higher risk of serious cardiac events. The association was strongest among people who get less than eight hours of sleep.

The analysis focuses on sleep timing variability—how much bedtime changes from day to day—rather than only total sleep duration. “Inconsistent bedtimes” means the schedule drifts, producing more fluctuation in circadian timing.

The findings suggest a dose-like relationship: shorter sleep appears to amplify the risk signal from irregular schedules. By contrast, the study found no clear link between irregular wake-up times and cardiac events.

This distinction matters because it points to a more specific target for intervention. If bedtime inconsistency is the key variable, clinicians and sleep researchers may prioritize strategies that stabilize bedtime routines—such as consistent sleep windows, evening light management, and behavioral adjustments to reduce schedule drift.

Cardiovascular outcomes are the outcome of interest because circadian disruption can affect blood pressure regulation, metabolic processes, inflammation pathways, and stress hormones—all systems that can contribute to heart disease risk. While the study is observational in nature (based on the summary), the direction of association aligns with those biological plausibility pathways.

The message for risk reduction is practical: maintaining a steady sleep routine could be another lever alongside established factors like smoking cessation, blood pressure control, and healthy diet.

In short, the research adds to evidence that sleep regularity is not just a comfort issue but could influence serious health outcomes, particularly for people who already fall short on sleep duration.