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Physiological Reports






e12970 (1-12)


The majority of the studies on VO2 kinetics in pediatric populations investigated gender differences in prepubertal children during submaximal intensity exercise, but studies are lacking in adolescents. The purpose of this study was to test the hypothesis that gender differences exist in the VO2 and heart rate (HR) kinetic responses to moderate (M) and heavy (H) intensity exercise in adolescents. Twenty-one healthy African-American adolescents (9 males, 15.8 ± 1.1 year; 12 females, 15.7 ± 1 year) performed constant work load exercise on a cycle ergometer at M and H. The VO2 kinetics of the male group was previously analyzed (Lai et al., Appl. Physiol. Nutr. Metab. 33:107–117, 2008b). For both genders, VO2 and HR kinetics were described with a single exponential at M and a double exponential at H. The fundamental time constant (τ1) of VO2 was significantly higher in female than male at M (45 ± 7 vs. 36 ± 11 sec, P < 0.01) and H (41 ± 8 vs. 29 ± 9 sec, P < 0.01), respectively. The functional gain (G1) was not statistically different between gender at M and statistically higher in females than males at H: 9.7 ± 1.2 versus 10.9 ± 1.3 mL min−1 W−1, respectively. The amplitude of the slow component was not significantly different between genders. The HR kinetics were significantly (τ1, P < 0.01) slower in females than males at M (61 ± 16 sec vs. 45 ± 20 sec, P < 0.01) and H (42 ± 10 sec vs. 30 ± 8 sec, P = 0.03). The G1 of HR was higher in females than males at M: 0.53 ± 0.11 versus 0.98 ± 0.2 bpm W−1 and H: 0.40 ± 0.11 versus 0.73 ± 0.23 bpm W−1, respectively. Gender differences in the VO2 and HR kinetics suggest that oxygen delivery and utilization kinetics of female adolescents differ from those in male adolescents. © 2016 The Authors.


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Original Publication Citation

Lai, N., Martis, A., Belfiori, A., Tolentino-Silva, F., Nasca, M. M., Strainic, J., & Cabrera, M. E. (2016). Gender differences in VO2 and HR kinetics at the onset of moderate and heavy exercise intensity in adolescents. Physiological Reports, 4(18), e12970. doi:10.14814/phy2.12970


0000-0002-3436-289X (Lai)

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