Metabolic cost of locomotion during treadmill walking with blood flow restriction

We explored whether interval walking with blood flow restriction (BFR) increases net metabolic cost of locomotion in healthy young men at their optimal walking speed. We also determined whether decreased walking economy resulting from BFR might be accompanied by an increase in ventilation relative to VO2 and VCO2 . Finally, we examined possible relationships between the changes in ratings of perceived exertion (RPE) and those obtained in minute ventilation (VE ) during walking with BFR. Eighteen healthy men (age: 22·5 ± 3·4 years) performed graded treadmill exercise to assess VO2max . In a randomized fashion, participants also performed five bouts of 3-min treadmill exercise with and without BFR at their optimal walking speed. Walking with BFR elicited an overall increase in net VO2 (10·4%) compared with that seen in the non-BFR condition (P<0·05). The participants also demonstrated greater VE and VE /VO2 values while walking with BFR (P<0·05). Conversely, VE /VCO2 was similar between conditions at each walking bout. We found no significant correlation between the changes in VE and RPE induced by walking with BFR (r = 0·38, P>0·05). Our results indicate that (i) BFR decreases net walking economy in healthy young men, even at their optimal walking speed; (ii) heightened ventilatory drive may explain a small proportion of BFR effects on walking economy; and (iii) the ventilatory responses to BFR walking may be largely independent of changes in perceived exertion and are likely matched to the flux of CO2 between muscles and respiratory centres.