Shorter sleep linked to increased hypertension risk

9 June 2009

MedWire News: Sleeping fewer hours is associated with higher blood pressure (BP) levels and an increased risk for developing hypertension, a US study suggests.

Both epidemiologic and short-term laboratory-based sleep studies have also previously pointed to an association between shorter sleep duration and increased BP. “Sleep loss may lead to increased sympathetic nervous activity, which could cause high BP if sleep loss were chronic,” say the authors.

Here, the researchers determined whether objectively measured sleep duration and quality predicted the 5-year incidence of hypertension and changes in systolic (S)BP and diastolic (D)BP levels in Chicago residents participating in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, a large, ongoing cohort study in the USA.

Kristen Knutson (University of Chicago, Illinois) and colleagues report that participants’ BP levels were measured in 2000 and 2001 and then again in 2005 and 2006, while their sleep parameters were measured twice using wrist actigraphy for 3 consecutive days in 2003 and 2005.

The 578 participants, who were not taking antihypertensive medications at baseline, slept for an average of 6 hours each night, and were awake approximately 11% of the time after falling asleep. Almost half (43%) slept less than 6 hours, and just 1% averaged 8 hours or more of sleep.

After adjusting for age, gender, and race, shorter sleep duration and lower sleep maintenance were independently associated with higher SBP and DBP levels (p<0.05).

Longitudinal analysis after excluding 73 participants who were taking antihypertensive medication at follow-up showed shorter sleep and poorer maintenance of sleep also predicted more adverse changes in SBP and DBP levels over 5 years (p<0.05).

Sleeping less was also associated with the development of hypertension, at 37% increased odds for hypertension with each 1-hour reduction in sleep duration. Sleep maintenance was not associated with incident hypertension, however.

Further analysis showed that African-American men slept much less than White women, and the authors speculate: “The well-documented higher blood pressure in African Americans and men might be partly related to sleep duration.”

Reporting in the Archives of Internal Medicine, the authors conclude: “Because of the major adverse health consequences of high BP, the identification of a new and potentially modifiable risk factor has clinical implications.

“Intervention studies are needed to determine whether optimizing sleep duration and quality can reduce the risk of increased BP.”

Arch Intern Med 2009; 169: 1055-1061