Reductions in Energy Expenditure After Aerobic and Resistance Exercise in Resistance-trained Males

Abstract

PURPOSE: The purpose of this study was to examine the effects of exercise mode and intensity on energy expenditure (EE) during and after five time-matched aerobic and resistance exercise protocols in resistance-trained (RT) males. METHODS: Fourteen RT males (mean±SD; age:24.2±4.0 yrs; body mass:84.7±13.3 kg; height:181.2±8.8 cm; and body fat:15.9±4.6%) completed five separate protocols on separate days ≥48 hrs apart in random order, each lasting 40 min in duration: continuous aerobic (continuous), high intensity interval aerobic (HIIT), strength endurance (2x20), traditional resistance (3x10), and high intensity resistance (4x6). EE was measured before, during, immediately post- (0-30 min), and delayed post-exercise (60-90 min) using indirect calorimetry. RESULTS: No significant differences in exercise EE were seen between aerobic protocols. EE during both aerobic protocols was significantly greater (p<0.0001) than any of the three resistance protocols. EE during 4x6 was significantly greater than 3x10 and 2x20 by 38±10 kcal (p=0.04) and 67±8 kcal (p<0.001), respectively. From 0-30 min post- exercise, a mean increase in EE of 6.2% was seen only following the 2x20 protocol as compared to baseline pre-exercise (p<0.05). From 60-90 min post-exercise, the 3x10, 4x6, and HIIT protocols showed significant mean reductions in EE of 10.7%, 8.7%, 7.1% (p<0.05) as compared to baseline pre-exercise, respectively. The combined EE from during and after exercise resulted in the same rank order as during exercise (least to greatest: 2x20, 3x10,4x6, continuous, and HIIT). CONCLUSIONS: Significant reductions in EE were found in the 3x10, 4x6, and HIIT protocols from 60-90 min post-exercise as compared to baseline pre-exercise. Continuous and HIIT protocols had the greatest EE during exercise when compared to the resistance protocols. These results have important implications on EE during and after exercise and should be considered when designing exercise training programs. Given the reductions found in EE 60-90 min post-exercise in the 3x10, 4x6, and HIIT protocols, special consideration should be given to post-exercise nutrition to avoid energy deficits which could negatively impact recovery. Supported by an ASPIRE I Grant from the University of South Carolina.