Erschienen in:
01.06.2011 | Original Article
Cardiac function and arteriovenous oxygen difference during exercise in obese adults
verfasst von:
Chantal A. Vella, Diana Ontiveros, Raul Y. Zubia
Erschienen in:
European Journal of Applied Physiology
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Ausgabe 6/2011
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Abstract
The purpose of this study was to assess cardiac function and arteriovenous oxygen difference (a-vO2 difference) at rest and during exercise in young, normal-weight (n = 20), and obese (n = 12) men and women who were matched for age and fitness level. Participants were assessed for body composition, peak oxygen consumption (VO2peak), and cardiac variables (thoracic bioimpedance)—cardiac index (CI), cardiac output (Q), stroke volume (SV), heart rate (HR), and ejection fraction (EF)—at rest and during cycling exercise at 65% of VO2peak. Differences between groups were assessed with multivariate ANOVA and mixed-model ANOVA with repeated measures controlling for sex. Absolute VO2peak and VO2peak relative to fat-free mass (FFM) were similar between normal-weight and obese groups (Mean ± SEE 2.7 ± 0.2 vs. 3.3 ± 0.3 l min−1, p = 0.084 and 52.4 ± 1.5 vs. 50.9 ± 2.3 ml kg FFM−1 min−1, p = 0.583, respectively). In the obese group, resting Q and SV were higher (6.7 ± 0.4 vs. 4.9 ± 0.1 l min−1, p < 0.001 and 86.8 ± 4.3 vs. 65.8 ± 1.9 ml min−1, p < 0.001, respectively) and EF lower (56.4 ± 2.2 vs. 65.5 ± 2.2%, p = 0.003, respectively) when compared with the normal-weight group. During submaximal exercise, the obese group demonstrated higher mean CI (8.8 ± 0.3 vs. 7.7 ± 0.2 l min−1 m−2, p = 0.007, respectively), Q (19.2 ± 0.9 vs. 13.1 ± 0.3 l min−1, p < 0.001, respectively), and SV (123.0 ± 5.6 vs. 88.9 ± 4.1 ml min−1, p < 0.001, respectively) and a lower a-vO2 difference (10.4 ± 1.0 vs. 14.0 ± 0.7 ml l00 ml−1, p = 0.002, respectively) compared with controls. Our study suggests that the ability to extract oxygen during exercise may be impaired in obese individuals.