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Impaired pressure natriuresis in obese youths
Paule Barbeau1, Mark S Litaker, Gregory A Harshfield
1Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Augusta, Georgia 30912, USA. pbarbeau@mail.mcg.edu
Objective:
To compare the response and recovery of blood pressure (BP) and sodium excretion (U(Na)V) in response to a behavioral stressor in overweight/obese and lean adolescents.
Research Methods And Procedures:
Twenty-five lean (12% to 20% body fat) and 59 overweight/obese (>25% body fat) normotensive adolescents were provided all meals for 3 days (average sodium intake, 4000 +/- 200 mg/d), before performing the stressor on the third day. There was a 2-hour pre-stress rest, followed by a 1-hour stress (involving a video game task), and a 2-hour recovery. Percentage of body fat was obtained from DXA. U(Na)V was measured hourly, whereas systolic BP and diastolic BP measurements were obtained at 15-minute intervals, and averaged for each 1-hour period.
Results:
There was no significant difference between the lean and overweight/obese group for the response of systolic BP and diastolic BP (group by time interaction, p = 0.60 and p = 0.64, respectively). However, the lean group had a significantly greater increase in U(Na)V in response to the stressor compared with the overweight/obese group (p = 0.02). U(Na)V remained elevated compared with baseline in both groups at the 1-hour (p
Discussion:
This study provided evidence that sodium regulation was impaired during a behavioral stress in overweight/obese individuals compared with lean individuals.