Energy expenditure and substrate utilization in older women after strength training: 24-h calorimeter results

M. S. Treuth, G. R. Hunter, R. L. Weinsier, S. H. Kell

Abstract

The purpose of this study was to examine the effects of strength training (ST) in healthy older women on 24-h energy expenditure (EE) and its components and on 24-h substrate utilization. Thirteen women (age 67 +/- 1 yr) exercised three times per week for 16 wk in a total body ST program. EE components and substrate utilization were determined for 24 h in an indirect room calorimeter before and after training. The ST invoked a 47% increase in upper body and a 66% increase in lower body strength (P < 0.001). Body weight, percent body fat, and fat-free mass did not change significantly; however, midthigh muscle area increased (55.2 +/- 3.1 vs. 60.4 +/- 2.3 cm2; P < 0.05). There are a significant increase in resting EE (5,017 +/- 218 vs. 5,473 +/- 213 kJ/day; P < 0.05) but no significant changes in sleeping EE (4,929 +/- 180 vs. 5,067 +/- 251 kJ/day), diet-induced thermogenesis (359 +/- 25 vs. 393 +/- 33 kJ/day), activity EE (682 +/- 84 vs. 381 +/- 117 kJ/day), or 24-h EE (6,054 +/- 188 vs. 6,247 +/- 243 kJ/day). The increase in resting EE was not significant after the increase in muscle area is taken into account. The 24-h nonprotein respiratory quotient decreased (0.90 +/- 0.01 vs. 0.82 +/- 0.01; P < 0.001), revealing a significant increase in 24-h fat oxidation (42 +/- 6 vs. 81 +/- 7 g/day) and a decrease in carbohydrate oxidation (180 +/- 14 vs. 113 +/- 10 g/day; both P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)