Longitudinal Analysis Of Pulmonary Function, Cardiorespiratory Fitness And Body Composition In Understudied Mexican Adolescents

Pulmonary function (PF), primarily assessed via forced vital capacity (FVC), and cardiorespiratory fitness (CRF), primarily measured by maximal oxygen consumption (VO2max), are influenced by body composition. While physical activity impacts PF and CRF, the longitudinal relationship among these variables in Mexican adolescents remains underexplored. PURPOSE: To analyze the longitudinal relationship between pulmonary function, cardiorespiratory fitness and body composition in Mexican adolescents. METHODS: This 20-week study included 35 females (Mean = 16.64, SD = 0.70 years) and 24 males (Mean = 17.07, SD = 0.78 years). The timeframe was selected to capture meaningful changes in adolescent development and fitness. Pulmonary function was measured by FVC using a Contec SP10 spirometer. Cardiorespiratory fitness was assessed by VO2max and heart rate (HR) using the Queens College Step Test. Body composition was assessed with an InBody 120 bioimpedance scale, which provided measures for muscle mass, fat mass, and visceral fat. Pearson correlations, assessing the strength and direction of relationships between variables, were used to evaluate associations, with significance set at p < .05. RESULTS: A significant positive correlation was found between FVC and muscle mass, r = .704, p < .001, suggesting that greater muscle mass may support enhanced pulmonary function. A moderate negative correlation was observed between FVC and body fat percentage, r = −.403, p = .002, suggesting that higher body fat may be associated with reduced pulmonary function. VO2max showed positive correlations with muscle mass (r = .775, p < .001) and BMI (r = .458, p < .001), highlighting muscle mass and BMI as indicators of cardiorespiratory capacity. HR correlated with body fat (r = .413, p = .001) and visceral fat r = .415, p = .001), suggesting higher fat levels may be associated with elevated HR during exercise. CONCLUSIONS: These results suggest a moderate to strong association between body composition, particularly muscle. Supported by: The resources were obtained from the CONAHCYT grant for graduate students (Support Number: 829846).