A good night’s sleep might be as important as exercise and diet when it comes to reducing patients’ cardiovascular disease risk, according to a landmark Spanish study.

After accounting for other risk factors, sleeping fewer than six hours increased the risk of non-coronary atherosclerosis by 27% compared with slumbering for 7-8 hours, the study of nearly 4000 bank employees found.

Fragmented sleep also increased the risk of plaque-filled non-coronary arteries by more than 34%, according to the study led by the Spanish National Center for Cardiovascular Research in Madrid.

The study was the first to use imaging to assess atherosclerotic plaque burden and accelerometers to measure sleep patterns, the authors reported in the Journal of the American College of Cardiology.