Relationship between maximum aerobic power and resting metabolic rate in young adult women

Abstract

Smith, D. A., J. Dollman, R. T. Withers, M. Brinkman, J. P. Keeves, and D. G. Clark. Relationship between maximum aerobic power and resting metabolic rate in young adult women. J. Appl. Physiol. 82(1): 156–163, 1997.—The literature is inconclusive as to the chronic effect of aerobic exercise on resting metabolic rate (RMR), and furthermore there is a scarcity of data on young women. Thirty-four young women exhibiting a wide range of aerobic fitness [maximum aerobic power (V˙o 2 max) = 32.3–64.8 ml ⋅ kg−1 ⋅ min−1] were accordingly measured for RMR by the Douglas bag method, treadmillV˙o 2 max, and fat-free mass (FFM) by using Siri’s three-compartment model. The interclass correlation ( n = 34) between RMR (kJ/h) and V˙o 2 max(ml ⋅ kg−1 ⋅ min−1) was significant ( r = 0.39, P < 0.05). However, this relationship lost statistical significance when RMR was indexed to FFM and when partial correlation analysis was used to control for FFM differences. Furthermore, multiple linear-regression analysis indicated that only FFM emerged as a significant predictor of RMR (kJ/h). When high- ( n = 12) and low-fitness ( n = 12) groups were extracted from the cohort on the basis ofV˙o 2 max scores, independent t-tests revealed significant between-group differences ( P < 0.05) for RMR (kJ ⋅ kg−1 ⋅ h−1) andV˙o 2 max(ml ⋅ kg−1 ⋅ min−1) but not for RMR (kJ/h), RMR (kJ ⋅ kg FFM−1 ⋅ h−1), and FFM. Analysis of covariance of RMR (kJ/h) with FFM as the covariate also showed no significant difference ( P = 0.56) between high- and low-fitness groups. Thus the results suggest that 1) FFM accounts for most of the differences in RMR between subjects of varyingV˙o 2 max values and 2) the RMR per unit of FFM in young healthy women is unrelated toV˙o 2 max.