Acute Resistance Exercise Effects on Blood Flow in Resistance-Trained Versus Untrained Individuals

Abstract

Data suggests that an acute bout of resistance exercise (ARE) increases forearm blood flow (FBF) and vasodilatory capacity compared to rest. However, the effects of training status on FBF and vasodilatory capacity at rest and during recovery from ARE are uncertain. PURPOSE: To compare the effects of resistance exercise training status on measures of vascular function at rest and recovery from ARE. METHODS: Fifteen resistance-trained (RT) individuals, and seven untrained (UT) individuals volunteered to participate. Measurements were taken after a 10min supine rest and 20min after ARE, or a control. Venous occlusion plethysmography was used to measure FBF and vasodilatory capacity, with 5min of occlusion (220mmHg) to induce reactive hyperemia. Area under the curve (AUC) was utilized to determine differences in blood flow. The ARE consisted of 3 sets of 10 repetitions at 75% 1-repetition maximum (1RM) on the leg press, leg curl, leg extension, lat pulldown, and chest press, with 2min of rest between sets and exercises. A 2x2x2 repeated measures ANOVA was used to evaluate group (RT, UT) across condition (ARE, control) and time (rest, recovery). If the ANOVA was significant, t-tests were used for post-hoc comparisons. RESULTS: Groups were similar (p>0.05) for age, height, and BMI, but not for weight (RT: 74.5±13.0kg; UT: 61.9±10.8kg, p=0.04). The 1RMs for chest press, leg curl, leg press, and lat pulldown were significantly different between groups (p<0.05), but not for leg extension (p=0.26). The total volume of exercise for the ARE was similar between groups (p=0.10). There were no significant (p>0.05) group differences at rest for FBF or vasodilatory capacity. There were no significant (p>0.05) 3-way interactions for FBF or vasodilatory capacity. There was a significant condition by time interaction for FBF (RT: rest: 2.9±1.1ml/100ml of tissue/min, recovery: 8.9±4.0ml/100ml of tissue/min; UT: rest: 3.1±1.1ml/100ml of tissue/min, recovery: 8.9±2.9ml/100ml of tissue/min; p<0.001) and AUC (RT: rest: 56.8±20.2units, recovery: 139.0±66.5units; UT: rest: 53.8±20.2units, recovery: 116.6±25.1units; p<0.001). CONCLUSION: These data demonstrate that acute resistance exercise significantly increases forearm blood flow and vasodilatory capacity regardless of training status.