Not getting a proper night's sleep increases the risk of high blood pressure in older men by 80 pc compared to those who got longer, less interrupted sleep, according to a new research.
Slow wave sleep (SWS), one of the deeper stages of sleep, is characterized by non-rapid eye movement (non-REM) from which it's difficult to awaken. It's represented by relatively slow, synchronized brain waves called delta activity on an electroencephalogram.
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 per cent 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, M.D., 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, Mass.
The researchers measured how long 784 men with an average age of 75 spent in SWS.
Those for whom SWS took up less than 4 per cent of sleep time 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 were the most strongly associated with the development of high blood pressure. This relationship was observed even after considering other aspects of sleep quality.
The findings remained consistent even after the researchers took weight, race and age into account.
The study has been detailed in Hypertension: Journal of the American Heart Association.