Acute Effects of Running and Blood Flow Restriction on Gas Exchange and Perceptual Responses

The purpose of this investigation was to examine gas exchange and perceptual responses during discrete running bouts performed at different peak running speeds with and without blood flow restriction (BFR). Twelve college-aged male subjects randomly performed four, 3-minute running bouts at 70%(BFR), 80%(BFR), and 90%(BFR) of their running speed at peak Vo(2) with BFR (applied bilaterally and most proximally on each leg) at 40% of total arterial occlusion pressure and 100%(NOBFR) of their running speed at peak Vo(2) without BFR. Separate 2-way, 4 (Speed [70%(BFR), 80%(BFR), 90%(BFR), and 100%(NOBFR)]) x 3 (Time [120, 150, and 180 seconds]), Bayesian repeated-measure models were performed to examine differences in oxygen consumption (Vo(2)), carbon dioxide production (Vco(2)), and minute ventilation (VE) as well as ratings of perceived exertion (RPE) and pain. Vo(2), Vco(2), and VE increased across running speeds and was similar between the 90%(BFR) and 100%(NOBFR) speeds for Vo(2) (Mean(diff) = -1.49 +/- 0.003 ml<middle dot>kg(-1)<middle dot>min(-1); 95% HDI: -4.8 to 1.8) and VE (Mean(diff) = -6.97 +/- 0.65 L<middle dot>min(-1); 95% HDI: -16.5 to 2.52). Ratings of perceived exertion was highest during the 90%(BFR) and 100%(NOBFR) speeds (90%(BFR) and 100%(NOBFR) > 80%(BFR) > 70%(BFR)), whereas pain was greater during the 90%(BFR) speed relative to the 70%(BFR) (Mean(diff) = -1.31 +/- -0.20 au; 95% HDI: -2.63 to -0.0165) and 100%(NOBFR) (Mean(diff) = 1.3 +/- 0.26 au; 95% HDI: 0.01-2.56) speeds. Applying BFR during 90%(BFR) of peak running speed induced comparable Vo(2) and VE responses as 100%(NOBFR) but was not associated with lower RPE and provoked more pain. Collectively, BFR exhibits a small, potentially negligible effect on gas exchange, which were largely speed dependent. Coaches and practitioners may consider treadmill running with BFR when reductions in exercise intensity are warranted.