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Is rapid vasodilation in response to single contractions impaired in human obesity?
Author(s) -
Harrell John,
Blain Gregory,
Limberg Jacqueline,
Mortensen Garrett,
Schrage William
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.804.13
Subject(s) - medicine , forearm , cardiology , vasodilation , blood pressure , endocrinology , surgery
Mechanical factors associated with muscle contraction may influence vascular responses to exercise. We tested the hypothesis that rapid vasodilation in response to single dynamic forearm contractions would be reduced in young obese adults (n=14, BMI 37±1) when compared to lean controls (n=15, BMI 21±1). We measured heart rate (ECG), blood pressure (BP, arm cuff & Finapress), and forearm blood flow (FBF, Doppler ultrasound) during a single forearm contraction (performed in triplicate) at 15, 30, and 50% of forearm maximal voluntary contraction (MVC). To account for higher BP in obese subjects, we assessed forearm vascular conductance (FVC=FBF/BP). Regardless of differences in baseline FVC, a given % change in FVC from baseline (%ΔFVC) will reflect the same % change in vessel radius (ie vasodilation). Therefore, we compared %ΔFVC between groups at each intensity. At rest, FVC was higher in obese (p<0.05). With contraction, the %ΔFVC was intensity‐dependent (50%>30%>15%) and peaked within 4–6 cardiac cycles after contraction in both groups. The %ΔFVC was similar at 15% between groups, but significantly lower in obese subjects at 30 and 50% MVC (p<0.05). These results indicate that with increasing intensity, obese adults exhibit reduced rapid vasodilation in response to a single dynamic forearm contraction. Research Support: NIH HL091397 and AHA 0815622G