Assessing Variability in Exercise Energy Expenditure Measurements: A Pilot Study

GNYACSM Original Research Abstract Assessing Variability in Exercise Energy Expenditure Measurements: A Pilot Study PHILIP ENG MS; KATHRYN WHYTE, PHD RDN New York Nutrition Obesity Research Center, Department of Medicine, Department of Pediatrics, Division of Molecular Genetics, Columbia University Irving Medical Center; New York City, NEW YORK Category: Graduate Advisor / Mentor: Whyte, Kathryn ([email protected]) ABSTRACT Whole-room indirect calorimetry (WRIC) serves as the gold standard for measuring human energy expenditure (EE) including 24hr EE and its components. It has been applied to multiple research fields to determine EE in energy balance studies. Due to response times in WRIC, for exercise EE, indirect calorimetry via metabolic cart (MET) serves as the gold standard. PURPOSE: The aim of this study was to determine if the WRIC can be utilized for measuring EE during exercise by comparing WRIC values of ventilated oxygen (VO2) and ventilated carbon dioxide (VCO2) to the same variables obtained from the current standard, MET. METHODS: Participants (n=6; 3 male, 3 female) were recruited to perform the exercise efficiency test (EET) x 2 in a repeated measures design. Each participant conducted two 14-minute graded cycle ergometer EETs at 60 RPM at 10 watts, 25 watts, 50 watts and 75 watts three times in a seven-day window. Study design included controls for biological variability. VO2 and VCO2 at each level of resistance (Watts (W)) at each day per method are outcome variables. Body composition (quantitative magnetic resonance) for collection of lean mass (LM) fat mass (FM) and total body water (TBW) were performed. Analysis of variance (ANOVA) were used to investigate intra individual variability and Bland Altman analyses were used to evaluate limits of agreement between the two methods at 50W. RESULTS: Means and ranges are listed for age (26.3±; 23-30y) BMI (26.9;22.8-33.9kg/m2). Means ± standard deviations for LM (49.2±6.9), FM (24.1±14.1) and TBW (41.4±5.7). ANOVAs run for each participant at level of W by DAY found significantly different values for VO2 and VCO2 for males only. Average VO2 and VCO2 at 50W for females for MET were 0.834±.09L/min and 0.701±.12L.min and for WRIC 0.585±.08L/min and 0.547±.09L/min. Average male VO2 and VCO2 at 50W for MET were 0.863±.12L/min and 0.694±.10L/min and WRIC 0.569±0.32L/min and 0.502±.25L/min. Bland Altman analyses do not demonstrate agreement between the methods for this sample. CONCLUSION: The preliminary data from this small cohort demonstrate differences between WRIC and MET for EET; this is primarily driven by male participants. Further testing is required to investigate if any actual mechanisms are driving the observed dimorphism between energy expenditure methods.