The effect of blood-flow-restricted interval training on lactate and H+ dynamics during dynamic exercise in man

Aim To assess how blood-flow-restricted (BFR) interval-training affects the capacity of the leg muscles for pH regulation during dynamic exercise in physically trained men. Methods Ten men (age: 25 +/- 4y; VO2max: 50 +/- 5 mL.kg(-1).min(-1)) completed a 6-wk interval-cycling intervention (INT) with one leg under BFR (BFR-leg; similar to 180 mmHg) and the other without BFR (CON-leg). Before and after INT, thigh net H+-release (lactate-dependent, lactate-independent and sum) and blood acid/base variables were measured during knee-extensor exercise at 25% (Ex25) and 90% (Ex90) of incremental peak power output. A muscle biopsy was collected before and after Ex90 to determine pH, lactate and density of H+-transport/buffering systems. Results After INT, net H+ release (BFR-leg: 15 +/- 2; CON-leg: 13 +/- 3; mmol.min(-1); Mean +/- 95% CI), net lactate-independent H+ release (BFR-leg: 8 +/- 1; CON-leg: 4 +/- 1; mmol.min(-1)) and net lactate-dependent H+ release (BFR-leg: 9 +/- 3; CON-leg: 10 +/- 3; mmol.min(-1)) were similar between legs during Ex90 (P > .05), despite a similar to 142% lower muscle intracellular-to-interstitial lactate gradient in BFR-leg (-3 +/- 4 vs 6 +/- 6 mmol.L-1; P < .05). In recovery from Ex90, net lactate-dependent H+ efflux decreased in BFR-leg with INT (P < .05 vs CON-leg) owing to lowered muscle lactate production (similar to(5)8% vs CON-leg, P < .05). Net H+ gradient was not different between legs (similar to 19%, P > .05; BFR-leg: 48 +/- 30; CON-leg: 44 +/- 23; mmol.L-1). In BFR-leg, NHE1 density was higher than in CON-leg (similar to 45%; P < .05) and correlated with total-net H+-release (r = 0.71; P = .031) and lactate-independent H+ release (r = 0.74; P = .023) after INT, where arterial [HCO3-] and standard base excess in Ex25 were higher in BFR-leg than CON-leg. Conclusion Compared to a training control, BFR-interval training increases the capacity for pH regulation during dynamic exercise mainly via enhancement of muscle lactate-dependent H+-transport function and blood H+-buffering capacity.

Automated summary

The study shows that blood-flow-restricted interval training can increase the capacity for pH regulation during dynamic exercise mainly via enhancement of muscle lactate-dependent H+ transport function and blood H+ buffering capacity.