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.