Going to bed at roughly the same time each day can cut the risk of heart disease in half, according to a new study. Researchers found that bedtime variations of just one to two hours per day can have serious effects on heart health.
Irregular Bedtime Group Faces Double the Heart Disease Risk: 10-Year Tracking Results
According to a study recently published in BMC Cardiovascular Disorders, a research team led by Dr. John La Puma, an internal medicine and sleep specialist, and Professor Srihari Naidu of New York Medical College, monitored 3,231 Finnish adults born in 1966. Participants wore wrist sleep monitors for seven days to measure bedtime, wake time, and sleep midpoint. The team then cross-referenced the data with Finland's national health registry system over the following decade, tracking heart attacks, strokes, heart failure hospitalizations, and cardiovascular deaths.
The study found that the irregular group, whose bedtimes varied by about two hours or more each day, had twice the risk of developing heart disease compared with the regular group. The result remained unchanged after controlling for common cardiac risk factors such as age and gender.
Notably, irregularity in wake times was not associated with the same risk. Only irregularity in falling-asleep times affected heart health.
"The risk was concentrated among those sleeping less than eight hours," Dr. La Puma said. "People who are both sleep-deprived and have irregular bedtimes are taking a double hit."
"Giving the Heart Jet Lag": Disruption of the Biological Clock Is the Cause
The reason bedtime is directly linked to heart health relates to the brain's biological clock. "The brain has a biological clock called the suprachiasmatic nucleus, made up of about 20,000 nerve cells," Dr. La Puma said. "This clock coordinates a series of nighttime recovery processes timed to when you fall asleep, including lowering blood pressure, reducing cortisol, slowing heart rate, and repairing blood vessels. When bedtimes vary by one to two hours each day, it's like giving your heart jet lag."
Professor Naidu added that irregular bedtimes cause systemic inflammation to build up, which in turn raises the risk of heart disease through pathways such as high blood pressure and obesity. The American Heart Association also recently officially added sleep regularity as an essential component of heart health, alongside diet, exercise, and smoking cessation.
Experts recommended establishing a consistent routine, such as dimming lights and avoiding blue-light screens starting an hour before bedtime. Professor Naidu recommended going to bed between 10 p.m. and midnight, maintaining the same time each day, and getting seven to eight hours of sleep. He stressed that those with sleep-related conditions such as sleep apnea can improve their heart health by consulting a specialist and receiving treatment.
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