Cardiac response to progressive cycle exercise in moderately obese adolescent females

Abstract

Purpose: To assess cardiac responses to exercise and cardiac functional capacity in moderately obese adolescent females.

Methods: Thirteen healthy females (mean age 13.6 +/- 1.5 years) with a body mass index from 30 to 43 kg per m(2) underwent maximal cycle testing. Cardiac responses were measured by Doppler echocardiogram, and gas exchange variables were determined with open circuit spirometry. Data were analyzed by independent Student's t-tests.

Results: Peak oxygen uptake relative to height(3.0) was significantly greater in the obese (570 +/- 90 ml m(-3)) compared to the nonobese controls (485 +/- 60 ml m(-3)). This difference was explained by a higher peak cardiac output (4.50 +/- 1.06 L m(-3) vs. 3.81 +/- 58 L m(-3)) and stroke volume (24 +/- 5 ml m(-3) vs. 19 +/- 3 ml m(-3)) in the obese. Maximal cardiac index was similar in the two groups. There was no evidence of myocardial dysfunction during exercise in either group.

Conclusions: Low aerobic fitness in obese adolescents as indicated by depressed peak VO(2) per kg body mass and limited endurance performance does not reflect decreased cardiac functional capacity.