Keeping a steady sleep schedule may matter for heart health as well as getting enough hours, according to preliminary research highlighted in an American Heart Association news release ahead of its Scientific Sessions 2026.
Researchers analyzed more than one million nights of wearable-tracker sleep data from 10,362 adults in the NIH All of Us Research Program, none of whom had heart or metabolic disease at the start. After a six-month baseline, participants were followed for a median of 3.7 years. Larger night-to-night shifts in sleep timing were linked to a 20% to 23% higher risk of serious cardiovascular events such as heart attack, stroke or heart failure.
The findings come from a research abstract that has not been peer reviewed, and the study was observational, so it cannot show cause and effect. Independent expert Marie-Pierre St-Onge of Columbia University said the data do not yet support a causal impact, but noted that stable schedules can also help people get enough sleep. Lead researcher Nguyen Minh Tuan Viet said regularity is something many people can control.