Predicting Minute Ventilation from Heart Rate in Adolescents: A Tool for Environmental Health Studies

Minute ventilation (VE) is central to understanding the interplay between air pollution and exercise. However, real-time measurement of VE in environmental health research is often limited by access to equipment and technical expertise. We aimed to (1) develop predictive equations for VE based on heart rate (HR) in adolescents using metabolic exercise testing data, (2) evaluate which demographic factors influenced model accuracy, and (3) compare our equations to previously published equations applied to our sample. We analyzed cardiopulmonary exercise test (CPET) data from 41 patients. VE was log-transformed, and generalized estimating equations (GEE) were used to model associations between HR and VE, adjusting for age, sex, race, ethnicity, and BMI. In the fully adjusted model, HR was a strong predictor of VE (p-value < 0.001); only sex was a significant covariate (p = 0.003). Stratification revealed a higher predicted VE at a given HR for males compared to females (ymale = 0.020x + 0.813 vs. yfemale = 0.019x + 0.708, where y = lnVE and x = HR) with a pseudo-R2 of 0.80 for males and pseudo-R2 of 0.82 for females. Our predictive equations had the lowest average percent difference between measured and predicted VE, whereas prior models under- or overestimated VE in our sample. Overall, sex-specific GEEs provide a practical method to estimate VE from HR in adolescents and can serve as tools to support exposure assessment and future applications in environmental health research.