London, Aug 30 (IANS) Poor sleep quality greatly raises the risk of high blood pressure among elderly men, says a study.

According to the study, lack of deep sleep was found to increase the likelihood by as much as 80 percent over a period of three-and-a-half years, the Daily Express reported.

In the study of 784 men with an average age of 75, researchers timed how long these men spent in ‘slow-wave sleep’ (SWS) – a deep state from which it is difficult to awaken.

Those for whom SWS took up less than four percent of sleep time were significantly more likely to develop high blood pressure or hypertension.

These individuals also had generally poorer sleep quality – measured by shorter duration, more awakenings during the night and more severe apnoea, a breathing problem in sleep.

SWS is believed to be important to learning and memory and linked to a range of physiological functions.

The findings, reported in the American Heart Association journal Hypertension, were not -influenced by body weight despite many of the men being overweight or obese, a recognised risk factor for high blood pressure.

Study co-author Susan Redline said: ‘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 this effect appears to be independent of the influence of breathing pauses during sleep.’