Abstract:
Background: Previously, 60 minutes was the shortest testing duration that was validated for measurement of exercise energetics (EXEE; kcal) utilizing whole room indirect calorimetry (WRIC). This comprised of 15, 30 and 15 minutes for warmup/stretching, steady state exercise and cool down periods, respectively (Rising et al, 2016). The objective of this analysis was to show the validity of extrapolating (EXP) 30-minute EXEE from the first 15 minutes of moderate intensity steady state cycling exercise in human subjects. Furthermore, changing the warmup/stretching and cool down times to 10 and 5 minutes, respectively reduces the total testing time to just 30-minutes.
Methods: EXEE data involving 15 healthy subjects (Age: 28.3±10.8 years, BMI: 25.1±3.9 kg/m2) from a prior study (Rising et al, 2016) were utilized for this analysis (Rising et al, 2025). In this study subjects cycled steadily at 65% heart rate max (Karvonen and Vuorimaa, 2016) for 30 minutes within the WRIC (10,000 liters). All 30- minute EXP metabolic data were calculated based on a theoretical 15-minutes of actual exercise. This equaled the average across the first 15 minutes of each subject’s exercise bout for ventilation (V;liters) of oxygen (VO2), carbon dioxide (VCO2) and EXEE (kcal) and multiplying by 30. The respiratory quotient (RQ; VCO2/VO2) was EXP from the mean across the respective first 15-minutes of exercise data. To validate the WRIC for simulated shorter duration EXEE testing, 10 propane combustion tests with a new larger burner (Coleman Model 5431B, The Colman Company, Wichita, Kansas USA) were utilized. The burn rate (g/minute) equaled the weight (g) prior to and after completion of each combustion test using a calibrated analytical balance (Mettler Toledo Model MS1602S/03, Mettler Toledo LLC, Columbus, OH) and divided by the total testing duration (minutes). Prior to the propane combustion tests, the Promethion metabolic instrumentation (Sable Systems International, North Las Vegas, NV) was calibrated according to the manufacturer’s instructions. All simulated metabolic parameters were calculated as described above for subjects and compared to that from the respective stoichiometries. Statistical analysis was performed utilizing SPSS (Ver 30, Chicago, IL).
Results: According to the following table, there were no differences between actual and EXP metabolic parameters for both the human subject EXEE and that simulated by propane combustion.
