Effect Of Aerobic Exercise With Blood Flow Restriction On Substrate Utilization And Energy Expenditure

Abstract

Blood flow restriction (BFR) added to aerobic exercise has the potential to elicit physiological adaptations. However, the acute effects of BFR on substrate utilization and energy expenditure (EE) remains unclear. PURPOSE: The purpose of this study was to examine the effects of intermittent BFR compared to low- (LIIE) and high-intensity interval exercise (HIIE) on EE and substrate utilization during exercise and recovery. METHODS: Participants randomly performed 3 interval (INT) exercise protocols: BFR, LIIE and HIIE. BFR and LIIE consisted of 10 INTs of 2-min of work at 70% of ventilatory threshold (VT) and 1-min of recovery (20 watts; W). During BFR, the cuffs were inflated to 80% of limb occlusion pressure (154 ± 17 mmHg) during each work INT and deflated during each recovery INT. HIIE consisted of 5 INTs at 140% of VT and 1-min of recovery (20 W). Breath by breath pulmonary oxygen uptake (VO2) and carbon dioxide production (VCO2) were recorded during a 15-min seated rest, exercise, and a 180-min seated recovery. Excess post exercise oxygen consumption (EPOC) magnitude was calculated as area under the curve from netVO2 (VO2 - VO2 at rest) during the first 90 minutes post-exercise. EE was calculated from VO2 during exercise and recovery. Fat oxidation (FatOx) and carbohydrate oxidation (CarbOx) rates were calculated from VO2 and VCO2 at rest, 1, 2 and 3 hrs post-exercise. Enjoyment was assessed post-exercise using the physical activity enjoyment scale (PACES). RESULTS: EPOC magnitude was similar among trials (LIIE = 4.87 ± 2.60 L*min-1, BFR = 6.59 ± 2.33 L*min-1, HIIE= 6.56 ± 2.01 L*min-1; p = 0.06). Total EE was different between BFR (321.6 ± 30.1 kcals), HIIE (254.5 ± 33.5 kcals), and LIIE (287.1 ± 25.5 kcals) (p<0.05). FatOx in BFR (1hr = 0.14 ± 0.01 g*min-1, 3hr = 0.11 ± 0.01 g*min-1) was greater than LIIE (1hr = 0.08 ± 0.02 g*min-1, 3hr = 0.9 ± 0.02 g*min-1), but not different from HIIE (1hr = 0.12 ± 0.02 g*min-1, 3hr = 0.09 ± 0.01 g*min-1) (main effect of trial; p<0.05). CarbOx during BFR (3hr = 0.16 ± 0.03 g*min-1) was less than LIIE (3hr = 0.19 ± 0.03 g*min-1) and HIIE (3hr = 0.23 ± 0.05 g*min-1) (main effect of trial). There were no differences in PACES scores. CONCLUSIONS: This study suggests that the addition of intermittent BFR to LIIE may result in greater EE but similar substrate utilization and enjoyment as HIIE, albeit at a lower work rate.