Lack of sleep linked to increased risk of high blood pressure
If you're middle age and sleep five hours or less a night, you may be increasing your risk of developing high blood pressure, according to research reported in Hypertension: Journal of the American Heart Association.
"Sleep allows the heart to slow down and blood pressure to drop for a significant part of the day," said James E. Gangwisch, Ph.D., lead author of the study and post-doctoral fellow at Columbia University's Mailman School of Public Health.
"However, people who sleep for only short durations raise their average 24-hour blood pressure and heart rate. This may set up the cardiovascular system to operate at an elevated pressure." Gangwisch said that 24 percent of people ages 32 to 59 who slept for five or fewer hours a night developed hypertension versus 12 percent of those who got seven or eight hours of sleep. Subjects who slept five or fewer hours per night continued to be significantly more likely to be diagnosed with hypertension after controlling for factors such as obesity, diabetes, physical activity, salt and alcohol consumption, smoking, depression, age, education, gender, and ethnicity.
The researchers conducted a longitudinal analysis of data from the Epidemiologic Follow-up Studies of the first National Health and Nutrition Examination Study (NHANES I). The analysis is based on NHANES I data from 4,810 people ages 32 to 86 who did not have high blood pressure at baseline. The 1982-84 follow-up survey asked participants how many hours they slept at night. During eight to 10 years of follow-up, 647 of the 4,810 participants were diagnosed with hypertension.
Compared to people who slept seven or eight hours a night, people who slept five or fewer hours a night also exercised less and were more likely to have a higher body mass index. (BMI is a measurement used to assess body fatness). They were also more likely to have diabetes and depression, and to report daytime sleepiness. "We had hypothesized that both BMI and a history of diabetes would mediate the relationship between sleep and blood pressure, and the results were consistent with this," Gangwisch said. Sleep deprivation has been shown previously to increase appetite and compromise insulin sensitivity.