Hormonal, immune, and oxidative stress responses to blood flow‐restricted exercise

Abstract

IntroductionHeavy‐load free‐flow resistance exercise (HL‐FFRE) is a widely used training modality. Recently, low‐load blood‐flow restricted resistance exercise (LL‐BFRRE) has gained attention in both athletic and clinical settings as an alternative when conventional HL‐FFRE is contraindicated or not tolerated. LL‐BFRRE has been shown to result in physiological adaptations in muscle and connective tissue that are comparable to those induced by HL‐FFRE. The underlying mechanisms remain unclear; however, evidence suggests that LL‐BFRRE involves elevated metabolic stress compared to conventional free‐flow resistance exercise (FFRE).AimThe aim was to evaluate the initial (<10 min post‐exercise), intermediate (10–20 min), and late (>30 min) hormonal, immune, and oxidative stress responses observed following acute sessions of LL‐BFRRE compared to FFRE in healthy adults.MethodsA systematic literature search of randomized and non‐randomized studies was conducted in PubMed, Embase, Cochrane Central, CINAHL, and SPORTDiscus. The Cochrane Risk of Bias (RoB2, ROBINS‐1) and TESTEX were used to evaluate risk of bias and study quality. Data extractions were based on mean change within groups.ResultsA total of 12525 hits were identified, of which 29 articles were included. LL‐BFRRE demonstrated greater acute increases in growth hormone responses when compared to overall FFRE at intermediate (SMD 2.04; 95% CI 0.87, 3.22) and late (SMD 2.64; 95% CI 1.13, 4.16) post‐exercise phases. LL‐BFRRE also demonstrated greater increase in testosterone responses compared to late LL‐FFRE.ConclusionThese results indicate that LL‐BFRRE can induce increased or similar hormone and immune responses compared to LL‐FFRE and HL‐FFRE along with attenuated oxidative stress responses compared to HL‐FFRE.