Physiological responses to interval endurance exercise at different levels of blood flow restriction.

Purpose: We aimed to identify a blood flow restriction (BFR) endurance exercise protocol that would both maximize cardiopulmonary and metabolic strain, and minimize the perception of effort.

Methods: Twelve healthy males (23 ± 2 years, 75 ± 7 kg) performed five different exercise protocols in randomized order: HI, high-intensity exercise starting at 105% of the incremental peak power (P ); I-BFR30, intermittent BFR at 30% P ; C-BFR30, continuous BFR at 30% P ; CON30, control exercise without BFR at 30% P ; I-BFR0, intermittent BFR during unloaded exercise. Cardiopulmonary, gastrocnemius oxygenation (StO), capillary lactate ([La]), and perceived exertion (RPE) were measured.