Going to bed at a different time every night in middle age may be a warning sign for future heart disease. A new study from the University of Oulu suggests that large fluctuations in bedtime can significantly increase the risk of serious cardiovascular events, especially in people who sleep for less than eight hours.
This study found a strong association between irregular bedtimes and increased likelihood of major heart-related events. People who slept less than 8 hours and whose sleep schedules varied widely faced about twice the risk compared to those with more consistent lifestyle habits. In contrast, irregular wake times showed no clear association with heart problems.
Major cardiovascular events in this study included conditions requiring specialized medical care, such as myocardial infarction and cerebral infarction.
“Previous studies have linked irregular sleep patterns to heart health risks, but this is the first time that we have separately investigated the independent associations between bedtime, wake time, mid-sleep variation and major cardiac events,” says Laura Nauha, a postdoctoral researcher at the University of Oulu.
Track your sleep patterns and long-term health
The researchers used activity monitors to measure sleep duration and duration, recording how long participants stayed in bed. The results showed that bedtime consistency was a particularly important factor.
“Our findings suggest that bedtime regularity, in particular, may be important for heart health, reflecting the rhythm of daily life and the degree to which it fluctuates,” says Nauha.
Long-term study reveals lasting effects
The study followed 3,231 people born in northern Finland in 1966. Their sleep habits were tracked over a one-week period at age 46, and their health was monitored for more than 10 years using health record data.
Daily life plays a big role in shaping heart health over time, according to Nauha. “Maintaining a regular sleep schedule is one factor most of us can influence.”
