The Effects of Type of Exercise on Ventilatory Efficiency (VE/VCO۲) in ۱۱-۱۶-Year-Old Healthy Individuals: A Randomized Clinical Trial

Background: The ventilatory equivalent for CO۲ (VE/VCO۲ ) is the simplest way to predict ventilatory efficiency. This study aimed to investigate the impact of treadmill and cycle ergometer exercise tests on ventilatory outcomes in healthy adolescents. Methods: In this clinical trial with cross-over design, ۵۲ adolescents aged ۱۱-۱۶ years old (age: ۱۳.۸±۰.۱۷ years, height: ۱۵۷.۴±۰.۹۵ cm, weight: ۵۱.۷۳±۱.۲۴ kg, represented as mean±standard error), went through treadmill and cycle ergometer exercise tests with a ۶-day wash-out during July-August ۲۰۱۹, Tehran, Iran. Through a RAMP (raise, activate, mobilise, and potentiate) protocol, participants were asked to perform the maximal treadmill or cycle ergometer exercise and continue the test until exhaustion. Gas exchange and heart rate (HR) were obtained breath by breath during the test. Time, HR, VE/VCO۲, minute ventilation) VE), end-tidal carbon dioxide pressure (PetCO۲), and dead space (VD) to tidal volume (VT) ratios (VD/VT) were transferred to the computer and recorded. All data were reported at two-time points: Anaerobic threshold (AT) V-slop method and peak. Independent t-test was then performed to compare the two types of exercises using SPSS ۱۶, and P˂۰.۰۵ was considered significant. Results: The results showed a significant difference in two points regarding the type of exercise for Time and VE/VCO۲, but for HR (P=۰.۰۰۴), VE (P=۰.۰۰۰۱), PetCO۲ (P=۰.۰۰۸), and VD/VT (P=۰.۰۰۴), a significant difference was only observed in AT point. Conclusion: Several physiological mechanisms that occurred during the development stage could affect individuals’ respiratory parameters; however, in general, the type of exercise test affected VE/VCO۲.