Pulmonary gas exchange responses during submaximal running with blood flow restriction

BACKGROUND: Blood flow restriction (BFR) implemented during aerobic exercise has been shown to alter cardiopulmonary responses under intensity-matched conditions, but its effects relative to maximal running speed and the gas exchange threshold (GET) remain unclear. The purpose of this investigation was to examine cardiopulmonary (oxygen consumption [V̇O2] and carbon dioxide production [V̇CO2]) responses during submaximal running with BFR relative to maximal running without BFR and the GET.METHODS: Fifteen aerobically trained females completed a custom ramp protocol to determine peak running speed and GET. Participants randomly completed four, three-minute running bouts at 70%BFR, 80%BFR, and 90%BFR of their top speed with BFR and 100%NOBFR of their top speed without BFR. Separate Bayesian repeated-measure models were performed to examine differences in V̇O2 and V̇CO2 during the final minute of the bouts.RESULTS: V̇O2 largely increased across bouts but was similar between the 80%BFR and 90%BFR (Meandiff=-2.26±-0.44 mL·kg-1·min-1) bouts as well as the 90%BFR and 100%NOBFR (Meandiff=-2.54±0.03 mL·kg-1·min-1) bouts. V̇CO2 also increased across bouts and was similar between the 90%BFR and 100%NOBFR (Meandiff=-0.25±-0.02 L·min-1) bouts. Relative to GET, V̇O2 and V̇CO2 was greater during each bout (GET < 70%BFR, 80%BFR, 90%BFR, and 100%NOBFR).CONCLUSIONS: Pulmonary gas exchange during submaximal running with BFR was comparable to maximal running without BFR (i.e., 90%BFR and 100%NOBFR) and greater than speed-matched running (i.e., relative to GET). Thus, BFR may serve as a training adjunct to lower the intensity (i.e., ≤10%) relative to the GET.