Cycling with blood flow restriction improves performance and muscle K⁺ regulation and alters the effect of anti‐oxidant infusion in humans

Abstract

Key pointsr Training with blood flow restriction (BFR) is a well-recognized strategy for promoting muscle hypertrophy and strength. However, its potential to enhance muscle function during sustained, intense exercise remains largely unexplored.r In the present study, we report that interval training with BFR augments improvements in performance and reduces net K + release from contracting muscles during high-intensity exercise in active men.r A better K + regulation after BFR-training is associated with an elevated blood flow to exercising muscles and altered muscle anti-oxidant function, as indicated by a higher reduced to oxidized glutathione (GSH:GSSG) ratio, compared to control, as well as an increased thigh net K + release during intense exercise with concomitant anti-oxidant infusion.r Training with BFR also invoked fibre type-specific adaptations in the abundance of Na + ,K + -ATPase isoforms (α 1 , β 1 , phospholemman/FXYD1).r Thus, BFR-training enhances performance and K + regulation during intense exercise, which may be a result of adaptations in anti-oxidant function, blood flow and Na + ,K + -ATPase-isoform abundance at the fibre-type level.Abstract We examined whether blood flow restriction (BFR) augments training-induced improvements in K + regulation and performance during intense exercise in men, and also whether these adaptations are associated with an altered muscle anti-oxidant function, blood flow and/or with fibre type-dependent changes in Na + ,K + -ATPase-isoform abundance. Ten recreationally-active men (25 ± 4 years, 49.7 ± 5.3 mL kg −1 min −1 ) performed 6 weeks of Danny Christiansen is a researcher based in the Section of Integrative Physiology at the Department of Nutrition, Exercise and Sports in Copenhagen. His research focuses on optimizing strategies that aim to enhance human physical performance and health by understanding the molecular factors that drive skeletal muscle adaptation. His work has involved the use of cold-water immersion, simulated altitude, anti-oxidant infusion and blood flow restriction in combination with exercise to study the regulation of muscle ion transport, blood flow, oxygenation and glucose metabolism in man.This article was first published as a preprint. Christiansen D, Eibye KH, Rasmussen V, Voldbye HM, Thomassen M, Nyberg M, Gunnarsson TGP, Skovgaard C, Lindskrog MS, Bishop DJ, Hostrup M, Bangsbo J. 2018. Cycling with blood flow restriction improves performance and muscle K + regulation and blunts the effect of antioxidant infusion in humans. bioRxiv. https://doi. J Physiol 597.9 interval cycling, where one leg trained without BFR (control; CON-leg) and the other trained with BFR (BFR-leg, pressure: ß180 mmHg). Before and after training, femoral arterial and venous K + concentrations and artery blood flow were measured during single-leg knee-extensor exercise at 25% (Ex1) and 90% of thigh incremental peak power (Ex2) with I.V. infusion of N-acetylcysteine (NAC) or placebo (saline) and a resting muscle biopsy was collected. After training, performance...

Training with blood flow restriction increases femoral artery diameter and thigh oxygen delivery during knee‐extensor exercise in recreationally trained men

“…The present study demonstrates that training with a substantial reduction (ß50%) in blood flow to exercising muscles (Christiansen et al 2019b) increases leg convective O 2 transport during both low-(23%) and high-intensity (13%), submaximal exercise in recreationally trained men (V O 2 max = 50 mL kg −1 min −1 ) ( Fig. 1).…”

Vascular and oxygenation responses of local ischemia and systemic hypoxia during arm cycling repeated sprints

“…Prior training studies performing repeated sprints in hypoxia have eluded to increased variation in perfusion during both leg cycling 4 and double poling. 10 Similar research has shown this response during acute leg cycling RST with different levels of BFR, 2 as well as after 6 weeks of single-leg cycling with BFR performing 3 sets of 3 × 2 min interval training, 24 and additionally with 4 weeks of single-leg knee extension with BFR. 25 The present arm cycling result was therefore expected.…”

Speeding of oxygen uptake kinetics is not different following low‐intensity blood‐flow‐restricted and high‐intensity interval training

“…Furthermore, several studies demonstrate that reduced blood flow to the exercising limbs produces beneficial adaptive responses that are likely to be responsible for speeded kinetics, such as increased muscle oxidative enzyme activity, capillary density in quadriceps (Conceição et al., ; Esbjörnsson et al., ) and enhanced microvascular filtration capacity in humans (as an index of capillarity; Evans et al., ). Together, these factors might be responsible for speeding kinetics (Rossiter, ) and increasing and exercise tolerance (Abe et al., ; Kancin & Strazar, 2011; Christiansen et al., ; de Oliveira et al., ).…”

“…Low‐intensity resistance or endurance exercise training, combined with blood‐flow restriction (BFR), is used as an alternative training method to accrue beneficial muscular training adaptations, among other benefits, especially in those for whom high‐mechanical loads are contraindicated. In particular, endurance BFR training increases several indices of aerobic function, including (Abe et al., ; de Oliveira, Caputo, Corvino, & Denadai, ; Park et al., ), exercise tolerance (Abe et al., ; Kancin & Strazar, ; de Oliveira et al., ) and intramuscular adaptations supporting endurance exercise (Christiansen, Eibye, Hostrup, & Bangsbo, ; Christiansen et al., ; Christiansen, Murphy, Bangsbo, Stathis, & Bishop, ). The potential mechanisms responsible for increased and exercise tolerance are debated, but include the following: increased stroke volume and cardiac output (Park et al., ); increased muscle capillarity and diffusive oxygen transport (Esbjörnsson et al., ; Evans, Vance, & Brown, ; Kacin & Strazar, ); and increased muscle oxidative enzyme activity (Esbjörnsson et al., ; Kaijser et al., ).…”