Cardiac function and arteriovenous oxygen difference during exercise in obese adults.
The purpose of this study was to assess cardiac function and arteriovenous oxygen difference (a-vO(2) 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 (VO(2peak)), 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 VO(2peak). Differences between groups were assessed with multivariate ANOVA and mixed-model ANOVA with repeated measures controlling for sex. Absolute VO(2peak) and VO(2peak) 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-vO(2) 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.
Department of Kinesiology, University of Texas at El Paso, 1101N Campbell, El Paso, TX 79902, USA. cvella@utep.edu
Chantal A
CA
Vella
Diana
D
Ontiveros
Raul Y
RY
Zubia
D000328:Adult; D001158:Arteries / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009765:Obesity / Q000378:metabolism* / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000502:physiology*; D014680:Veins / Q000378:metabolism; D055815:Young Adult