Inadequate sleep linked to high blood pressure: Study

By Dr. Ananya Mandal, MDAug 31 2011

According to the latest research poor sleep may be linked to high blood pressure.

In the study, men with the lowest level of the deeper stages of slumber, known as slow-wave sleep, had an 80 percent higher chance of developing high blood pressure than men with the highest level of this restorative sleep. The link held regardless of other factors, such as obesity or how long the men slept.

“Reductions in the deepest stage of sleep is specifically associated with an increased risk of developing high blood pressure,” said Dr. Susan Redline, the Peter C. Farrell Professor of Sleep Medicine at Brigham & Women's Hospital, Beth Israel Deaconess Medical Center and Harvard Medical School.

The study, published in the Aug. 29 online edition of the journal Hypertension, reinforces other research that has linked sleep problems with a raised risk of obesity and cardiovascular problems, among other ills.

For this study Redline evaluated 784 men, average age 75, who were part of the Outcomes of Sleep Disorders in Older Men Study. In 2003-05, the men did not have high blood pressure. Ideally, blood pressure readings should be below 120/80. When they returned for a follow up in 2007-09, the investigators found that 243 men had developed high blood pressure.

The men were then divided into four groups, from those with the lowest amount of slow-wave sleep to the highest. After accounting for age, race, body mass index and other factors, the link between low slow-wave sleep and higher blood pressure held. Even when the researchers took into account sleep-disordered breathing and the length of overall sleep, the link held.

Slow-wave sleep decreases with age, Redline said. She added, “Kids may have 40 percent slow-wave sleep 1/8 of total sleep 3/8,” but healthy adults, overall, may have only about 25 percent.

In this study, the men averaged 11.2 percent of slow-wave sleep, she said. Those in the lowest of the four groups averaged only 4 percent or less. Other studies have shown that slow-wave sleep is lower in older men than in women.

While the study found an association between slow-wave sleep and high blood pressure, it did not prove a cause-and-effect she said. Researchers say they would expect a similar effect in women.

The British Heart Foundation said it was important for everyone to prioritize sleep. Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said, “Whilst this study does suggest a link between lack of sleep and the development of high blood pressure, it only looked at men aged over 65. We would need to see more research in other age groups and involving women to confirm this particular association. However, we do know more generally that sleep is essential for staying healthy. It's important we all try to make sleep a priority and get our six to eight hours of shut-eye a night.”