Salivary proteomics and metabolic responses to resistance training with and without blood flow restriction in young...

Blood flow restriction (BFR) has been applied as alternative strategy to reproduce the effects of conventional high-load intensity training (HI) while training with low-loads (LI). Therefore, the aim of this research was to evaluate the salivary proteomic and metabolic responses to different resistance training in young adults.Ten participants were selected and underwent to training with LI (30 %1RM - one repetition maximum) plus BFR vs. HI (70 %1RM) without BFR, at 48 h-interval. Stimulated saliva was collected before and immediately after the sessions, while breath-by-breath oxygen uptake (VO₂) was measured during and after each session. Arterial blood samples for lactate concentration measurement (in EqO_2[La]) were taken at 1^st minute of resting between each exercise. For HI, there was an increase in two actin cytoplasmic isoforms and two immunoglobulin isoforms and a decrease of six hemoglobin isoforms. For LI-BFR, there was an increase in two hemoglobin isoforms, and the same immunoglobulin isoforms (t-test, p < 0.05). No differences were significant between HI and LI + BRF training regarding the total energy demand (in mlO₂), absolute oxygen values (mlO₂) for oxidative response (VO_2ON), glycolytic (EqO_2[La]), and oxygen debt (VO_2OFF) (p > 0.05). Both HI and LI + BFR protocols modulated immune system activity and exhibited divergent hemoglobin patterns. SIGNIFICANCE: The current study, which identified protein from saliva samples, a non-invasive method, and analyzed physiological markers, enabled the comparison of different resistance exercise protocols. Although no significant differences were observed in the metabolic responses to each protocol, which highlights the potential of LI + BRF to reproduce a high-intensity training stimulus, the changes in salivary protein profiles indicate specific functional adaptations that may become evident over time.