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Sep 27, 2011

Deep Sleep Lowers Risk for High Blood Pressure

The relationship between chronic sleep problems and increased risk for cardiovascular disease has been validated by multiple past scientific studies. A newer study published in Hypertension indicates that quality of sleep, not just quantity of sleep, plays a major role in risk for high blood pressure.

Interested in analyzing the effects of deep sleep on health, researchers studied nearly 800 healthy men with no signs of high blood pressure at the time of enrollment. Over the period of 3 ½ years, participants had their blood pressures checked periodically and had their sleep monitored via a home machine. Researchers were particularly concerned with slow-wave stages of sleep since these correlate with the deepest hours of sleep. During a normal night's sleep, slow-wave stages typically makeup about 25% of total sleep, usually lasting for 1 ½ to 2 hours.

Results of the study showed that men experiencing slow-wave (deep sleep) for the shortest amounts of time were the most likely to develop hypertension. Rather than getting the benefit of deep sleep lasting for 25% of their total sleep, the men at most risk for elevated blood pressure only experienced deep sleep for up to 4% of their total sleep every night. Men with the lowest levels of deep sleep also tended to have more sleep apnea and sleep less hours overall.

Although this study population only included men, Dr. Susan Redline, author and professor of sleep medicine at Harvard Medical School and Brigham and Women's hospital, believes that lack of deep sleep probably affects women similarly.

Many factors can get in the way of a good night's deep sleep. Some of the common causes of sleep interruption include poor sleep habits, loud snoring, sleep apnea, restless legs, physical pain or discomfort, chronic stress, and side effects from some medications. Deep sleep also tends to decrease as we age, particularly when there are dramatic changes in hormone levels as well as life situations. The types and amounts of physical and mental activities we engage in during the day also play an important role in quality of sleep.

By developing healthier sleep habits (i.e. getting to bed earlier, having relaxing routines before bedtime, sleeping in a dark room, etc) and addressing any other factors that may be interfering with our sleep, we will not only improve our deep sleep and wake up feeling more refreshed, but also improve our cardiovascular health. Once again, sleep proves to be a vital key to optimal health and well-being!

Dr. Shana McQueen