Reduced slow wave sleep (SWS) is a powerful predictor for developing high blood pressure in older men, according to new research in Hypertension: Journal of the American Heart Association.
Researchers from the Outcomes of Sleep Disorders in Older Men Study (MrOs Sleep Study) found that people with the lowest level of SWS had an 80% increased risk of developing high blood pressure.
"Our study shows for the first time that poor quality sleep, reflected by reduced slow wave sleep, puts individuals at significantly increased risk of developing high blood pressure, and that this effect appears to be independent of the influence of breathing pauses during sleep," said Susan Redline, MD, the study’s co-author and Peter C. Farrell Professor of Sleep Medicine in the Department of Medicine at Brigham and Women’s Hospital and Beth Israel Deaconess Medical Center, Harvard Medical School, in Boston.
Men who spent less than 4% of their sleep time in SWS were significantly more likely to develop high blood pressure during the 3.4 years of the study. Men with reduced SWS had generally poorer sleep quality as measured by shorter sleep duration and more awakenings at night and had more severe sleep apnea than men with higher levels of SWS. However, of all measures of sleep quality, decreased SWS was the most strongly associated with the development of high blood pressure. This relationship was observed even after considering other aspects of sleep quality.
In the Sleep Heart Health Study, another large cohort study, researchers found that men were more likely to have less SWS than women. Men were also at an increased risk of high blood pressure when compared to women. The current study raises the possibility that poorer sleep in men may partly explain the male gender predisposition to high blood pressure.
"Although women were not included in this study, it’s quite likely that those who have lower levels of slow wave sleep for any number of reasons may also have an increased risk of developing high blood pressure," Redline said.
Slow wave sleep has been implicated in learning and memory with recent data also highlighting its importance to a variety of physiological functions, including metabolism and diabetes, and neurohormonal systems affecting the sympathetic nervous system that contribute to high blood pressure, researchers said.