blood pressure

Inadequate sleep raises BP risk in women

Women who regularly get less than seven hours of night sleep may have a higher risk of developing high blood pressure.

A number of previous studies have linked poor sleep quality to an increased risk of high blood pressure, diabetes and heart disease. Much of the research was focused on people with the breathing disorder - sleep apnoea, but some evidence suggests that sleep deprivation, in the absence of any overt sleep disorder, also takes a health toll.

Researchers from the Warwick Medical School in Coventry used data from a long-term health study of 10,300 white British civil servants aged between 35 and 55 years old. The researchers focused on participants who were free of high blood pressure in the 1997-1999 phase of the study and were reassessed in 2003-2005. During these two phases, 76 per cent and 68 per cent, respectively, of the original group were included in the evaluations. At both examinations, hypertension was defined as blood pressure more than 140/90 mm Hg or regular use of anti-hypertensive medications. At reassessment, 20 per cent of the study participants were newly diagnosed with high blood pressure, and the risk was greater among women who slept for shorter durations. Compared with women who said they typically got seven hours of sleep at night, those who slept for six hours were 42 per cent more likely to develop high blood pressure, while those who routinely slept no more than five hours had a 31 per cent higher risk. Risk factors for heart disease, such as smoking, being overweight or having a sedentary lifestyle, did partially contribute to the relationship. However, an independent link between sleep and blood pressure still remained. This could be because sleep deprivation might contribute to high blood pressure by keeping the nervous system in a state of hyperactivity, which in turn affects systems throughout the body, including the heart and blood vessels.

There was, however, no clear relationship between amount of sleep and blood pressure among men. The findings suggest there may be a "gender-specific" relationship between sleep deprivation and high blood pressure. However, the underlying reason is still not known. Further studies are needed to confirm that sleep duration, itself, affects blood pressure levels, and why these effects might be different in women and men.