Increasing daytime physical activity may improve the normal decline in blood pressure that occurs at nighttime in postmenopausal women, according to a report in the American Journal of Hypertension.
Blood pressure drops about 10% at night in healthy individuals. A smaller drop, termed blunted dipping, is considered a cardiovascular risk factor in men, because the heart and blood vessels are working harder than they should be during sleep. Few studies have examined nocturnal blood-pressure variations in women.
A research team led by Duke University administered 24-hour blood-pressure tests to 102 women in their mid-60s, roughly half of whom had heart disease. A wrist monitor recorded physical activity, and blood pressure was recorded about every half-hour. Women whose nighttime blood pressure dropped less than 10% were considered nondippers. Readings indicated blood pressure dropped less than 10% in 78% of heart-disease patients and 50% of controls. Compared with controls, women with heart disease had significantly higher nighttime systolic blood pressure, the top number in a blood-pressure reading and the most important in assessing cardiovascular risk, researchers said. There were no significant differences in diastolic readings. After accounting for individual differences, women who were more physically active were more likely to show a healthy nighttime blood-pressure dip, the study found.
Blunted dips might be common in older subjects from both men and women groups not only in women. Also the blood-pressure-cuff inflations might affect the result by disrupting the subjects' sleep. This in turn may contributed to higher night readings. This study does not explain why women who were more physically active were more likely to show a healthy nighttime blood-pressure dip. A further study about the relationship between active lifestyle and healthy nighttime blood-pressure dip should also be conducted to support the result.