NEW ORLEANS — Obesity blunts the normal pattern of nocturnal blood pressure dipping, and this might be one mechanism through which obesity contributes to adverse cardiovascular outcomes, findings from a recent study suggest.
Blood pressure normally drops by 10%–20% nightly during sleep, compared with waking hours during the day, and studies have shown that nondipping (defined as less than a 10% decrease in blood pressure at night) is associated with increased cardiovascular morbidity and mortality, Dr. Otelio Randall reported in a poster at a meeting sponsored by the International Society on Hypertension in Blacks.
Hourly blood pressure measurements were taken in 200 obese African American patients who were classified into three groups on the basis of their body mass index, in kg/m
The mean percentage of dipping was 8.6% in those with a BMI of less than 40, 8.4% in those with a BMI of 40–49, and 3.9% in those with a BMI of 50 or greater. Those with a BMI of at least 50 had a significantly smaller decrease in nocturnal blood pressure than the other two groups.
“Nondipping and reverse dipping are known to be associated with the potential risk for target organ damage. The high rates of nondipping and reverse dipping in this obese population reinforces the need to reduce BMI and improve hemodynamic and lipid profiles through lifestyle changes,” Dr. Randall said.