Intra-Assessment Resting Metabolic Rate Variability Is Associated with Cardiometabolic Risk Factors in Middle-Aged Adults.

The intra-assessment resting metabolic rate variability is related to cardiometabolic health, as suggested by previous literature. We studied whether that variability (expressed as coefficient of variation [CV; %]) for oxygen consumption (VO), carbon dioxide production (VCO), respiratory exchange ratio (RER), and resting energy expenditure (REE) is similar between men and women, and if is similarly associated with cardiometabolic risk factors. Gas exchange in 72 middle-aged adults was measured by indirect calorimetry. Anthropometrics and body composition, cardiorespiratory fitness, circulating cardiometabolic risk factors, and heart rhythm parameters were also determined. Men and women presented similar intra-assessment resting metabolic rate variability (all > 0.05). Notably, in men, CV for RER was positively associated with BMI and adiposity (both standardized β = 0.35, Ps ≤ 0.048), while CVs for VO, VCO, and REE were negatively associated (standardized β ranged from -0.37 to -0.46, all ≤ 0.036) with cardiometabolic risk factors. In women, CVs for VCO and REE were negatively associated with adiposity (both standardized β = -0.36, Ps ≤ 0.041) and cardiometabolic risk Z-score (standardized β = -0.40 and -0.38, respectively, Ps ≤ 0.05). In conclusion, intra-assessment resting metabolic rate variability could be considered an indicator of cardiometabolic health in middle-aged adults.