Blood Flow Restricted Resistance Exercise in Well-Trained Men: Salivary Biomarker Responses and Oxygen Saturation Kinetics

Eserhaut, DA, DeLeo, JM, and Fry, AC. Blood flow restricted resistance exercise in well-trained men: Salivary biomarker responses and oxygen saturation kinetics. J Strength Cond Res 38(12): e716-e726, 2024-Resistance exercise with continuous lower-limb blood flow restriction (BFR) may provide supplementary benefit to highly resistance-trained men. Thus, the purpose of this study was to compare cardiovascular and salivary biomarker responses, along with skeletal muscle oxygen saturation (SmO2) during passive lower-limb BFR (pBFR), BFR resistance exercise performed to task failure (BFR+RE), and volume-matched resistance exercise (RE). A within-subjects, repeated measures design was used. Nineteen men (x̄±SD: relative squat 1RM: 1.9 ± 0.3 kg·bw-1) reported for 3 visits. First, body composition, blood pressure, back squat, and leg extension 1 repetition maximums (1RM) were assessed. Resting systolic blood pressure and proximal thigh circumferences were used to estimate arterial occlusion pressures (eAOP). Visit 1 involved pBFR, where BFR cuffs were inflated to 80% eAOP around the proximal thighs for 10 minutes while subjects were seated in a leg extension machine. Then, 24-120 hours later, 4 sets of bilateral seated leg extensions at 30% 1RM were performed to momentary task failure with 1-minute rest at the same 80% eAOP. After 72-120 hours rest, subjects matched the repetition performances from BFR+RE at 30% 1RM for the RE condition. BFR+RE elicited greater (p ≤ 0.05) heart rates, systolic, and diastolic blood pressures relative to pBFR and RE. Significantly elevated (p ≤ 0.05) blood lactate, salivary cortisol concentrations, and α-amylase activity occurred following BFR+RE relative to pBFR and RE. BFR+RE also induced blunted (p < 0.001) SmO2 interset resaturation rates compared with RE. In trained men, continuous BFR+RE seems to significantly alter acute physiological responses to a greater degree than either pBFR alone or volume-matched RE.