Poor Sleep Linked to Hard-to-Treat Hypertension

Nov 03, 2012 | Updated Jan 02, 2013

Here's some sobering and serious news for women: Sleeping poorly may double your risk of a form of high blood pressure that is not easily treated.

In a study presented at the American Heart Association High Blood Pressure Research 2012 Scientific Sessions, researchers from Italy's University of Pisa said they'd found a strong association between poor sleep quality and resistant hypertension in women. Resistant hypertension is a form of high blood pressure that does not respond to treatment, including use of blood-pressure lowering medications. The current study defined resistant hypertension as high blood pressure that fails to respond to treatment using three or more high blood pressure medications. Researchers in this study also examined a possible relationship between depression and resistant hypertension.

The study included 234 adults who were already being treated for high blood pressure in an outpatient hypertension program, a group that was evenly split between men and women. Researchers analyzed data on sleep quantity and sleep quality, depression and anxiety, and risk factors for cardiovascular problems.

When it came to sleep duration, researchers found:

• The average amount of daily sleep among participants was 6.4 hours. This measurement was roughly the same for men and women.
• Of those studied, 49 percent slept fewer than six hours daily.

But it was sleep quality, not sleep quantity, that researchers determined had a link to the risk of resistant hypertension. When examining sleep quality, researchers found that women were significantly more likely to experience poor sleep quality than men:

• Of the women studied, 46 percent had poor sleep quality.
• Of the men studied, 30 percent experienced poor sleep quality.

Researchers also found that women had higher rates of depression, more than double that of men:

• Of the women studied, 20 percent had depressive symptoms.
• Of the men studied, 7 percent had symptoms of depression.

Overall, 15 percent of the study population was found to be suffering from resistant hypertension. When looking at the relationship between resistant hypertension and sleep quality, researchers found that among women, those who had resistant hypertension were five times as likely to also have poor sleep quality. They found no similar association between poor sleep quality and resistant hypertension among men.

Investigating a possible association between depression and resistant hypertension, researchers found similar results. Women who had resistant hypertension were more likely to show signs of depression than those without. And again, the study results produced no similar association between depression and resistant hypertension among men.

There's a lot to take note of here. First, the researchers found sleep quality -- not quantity -- was a significant factor in the link between resistant hypertension and sleep. Second, the differences between men and women are striking and potentially significant. It's too early to know, on the basis of an individual study, whether women are more at-risk than men to resistant hypertension on the basis of their sleep. But we do know that men and women experience the effects of sleep differently and have different vulnerabilities when it comes to the health consequences of sleep problems. We need more research in this area to better understand not only the effects of disrupted sleep on high blood pressure, but also how the risks for men and women may differ.

There's much we don't yet know about the relationship between sleep and high blood pressure, but we have seen other research that shows a link between the two in men and women:

• One study found men who were deprived of deep sleep were more likely to develop hypertension during their older years. Researchers examined the sleep patterns of 784 men ages 65 and older. None of the men had high blood pressure at the outset of the study. Over a period of 3.4 years, approximately 30 percent of these men developed hypertension. The men who developed hypertension were significantly more likely to spend less time in the stage of deep sleep, or slow wave sleep, than men who remained free of high blood pressure.

• Another study of nearly 6,000 men and women ages 40-100 looked at the relationship between sleep quantity and hypertension. They found that sleeping fewer than seven hours a night was associated with an increased risk of high blood pressure. Sleeping fewer than six hours per night was associated with a particularly high risk. This study also found that sleeping more than eight hours was associated with an elevated risk for hypertension.

Nearly one-third of men and women in the United States suffer from high blood pressure, which without treatment can over time cause serious health complications, including heart attack and stroke. We don't know everything we need to, yet, about the relationship between sleep and hypertension or the ways it may affect men and women differently. But here's what we do know: Sleep, more specifically high-quality sleep, can play an important role in protecting your cardiovascular health. Getting enough sleep -- and the right kind of restorative sleep -- may help to reduce your risk of high blood pressure.

Sweet Dreams,
Michael J. Breus, PhD
The Sleep Doctor™

Everything you do, you do better with a good night's sleep™
Twitter: @thesleepdoctor

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