Relationship between submaximal oxygen uptake, detailed body composition, and resting energy expenditure in overweight subjects

Abstract

Objective: We investigated the impact of detailed body composition on aerobic fitness to determine whether regional components of fat mass have independent effects on VO 2submax, and whether VO 2submax and detailed body composition independently explain variation in REE. Methods: 71 healthy adults (80% female, 20% male, BMI 28.2–43.8 kg/m 2) were investigated. Body composition was measured by the four‐compartment model together with whole body magnetic resonance imaging (MRI) to assess high and low metabolic rate organs and regional fat depots. VO 2submax was estimated at 75% of predicted maximum heart rate. Results: There was a strong association between VO 2submax and FFM and all organ masses except for heart. Skeletal muscle mass accounted for 34.8% of the variance in VO 2submax. In addition, subcutaneous adipose tissue (SAT) of extremities explained additional 14.4%. FFM and FM explained 71.3% of the variance in REE. Including the components of FFM and FM, the explained variance in REE increased by about 5.8%; skeletal muscle mass explained 70.0% of the variance in REE and kidney and liver masses explained additional 7.1%. VO 2submax correlated with REE. Taking into account body composition, VO 2submax did not add to the variance in REE. Conclusion: FFM is a determinant of both VO 2submax and REE. Modeling either REE or VO 2submax from individual components of FFM, about 77.1% of variance in REE (by muscle, liver and kidneys mass) and 34.8% of variance in VO 2submax (by skeletal muscle mass) could be explained. FM explained additional variance in REE, whereas SAT of extremities added to the variance in VO 2submax only. Am. J. Hum. Biol. 27:397–406, 2015. © 2014 Wiley Periodicals, Inc.