New applications of cardiopulmonary exercise testing parameters characterize age-related changes in exercise...

Age-related changes in exercise performance during adolescence are complex because of progressive physical and functional changes, in which multiple factors are involved.

Peak and submaximal cardiopulmonary exercise testing (CPET) parameters were studied in healthy children and adolescents.

Total 303 subjects were divided into six groups by ages and sex: ≤11 years old (yo) (28/22 for males/females), 12-15 yo (61/98), and ≥16 yo (52/42). Rest and peak heart rate (HR) were comparable in all groups. Absolute peak values of oxygen consumption ( $\dot{V}$ O2), work rate (WR), and oxygen pulse (OP) were higher in older age groups in both sexes, proportionally to the larger body size. When weight-indexed, these peak values were comparable in all male groups but were significantly lower in older female groups ≥12 yo than in ≤11 yo group. Submaximal slope parameters, oxygen uptake efficiency slope (OUES) and Δ $\dot{V}$ O2/ΔHR (oxygen pulse slope), demonstrated the same age-dependent trend as peak $\dot{V}$ O2 in both sexes. The effects of weight on p $\dot{V}$ O2 were progressively enhanced with age only in males, suggesting higher muscle mass and enhanced oxidative metabolism in older males. Exercise endurance beyond anaerobic threshold was augmented in older ages, more prominent in males, indicated by the relationship between ventilatory anaerobic threshold and p $\dot{V}$ O2. Age-dependent augmentation in ventilatory oxygenation efficiency was only noted in males.

Exercise performance during adolescence involves multiple factors reflecting somatic growth, functional maturation, and puberty-related body compositions. Significant sex differences were noted in older adolescents.