High-pressure blood flow restriction with very low load resistance training results in peripheral vascular adaptations similar to heavy resistance training

OBJECTIVE: To investigate vascular adaptations to eight weeks of resistance exercise, with and without different pressures of blood flow restriction (BFR), in the upper and lower body.

APPROACH: Forty individuals (men  =  20, women  =  20) completed eight weeks of resistance exercise at very low loads (15% of one-repetition maximum (1RM)), with two levels of BFR (40% arterial occlusion pressure (AOP), 80% AOP), without BFR, and 70% of 1RM. Vascular conductance and venous compliance were measured via plethysmography before and following training in the forearms and in the calves.

MAIN RESULTS: Values reported as means (95% confidence intervals). Pre to post changes in vascular conductance occurred only in the high-pressure conditions (upper body:  +8.29 (3.01-13.57) ml · mmHg-1; lower body:  +7.86 (3.37-12.35) ml · mmHg-1) and high-load conditions (upper body:  +8.60 (3.45-13.74) ml · mmHg-1); lower body:  +7.20 (2.71-11.69) ml · mmHg-1) only. In the upper body, the change was significantly greater in the high-pressure and high-load conditions compared to the change observed in the low-pressure condition (-0.41 (-5.56, 4.73) ml · mmHg-1). These changes were not greater than the change observed in the low-load condition without pressure (+1.81 (-3.47, 7.09) ml · mmHg-1). In the lower body, the change in the high-pressure and high-load conditions were significantly greater than the changes observed with low-load training with (-0.86 (-5.60, 3.87) ml · mmHg-1) and without (-1.22 (-5.71, 3.27) ml · mmHg-1) a low pressure. Venous compliance increased in all groups in the upper body (+0.003 (.000 08, 0.006) ml · 100 ml-1 · mmHg-1) only, with no changes in the lower body.

SIGNIFICANCE: High-pressure BFR causes adaptations in vascular function following eight weeks of training at mechanical loads not typically associated with such adaptations.