Effects of blood flow restriction training on cardiovascular autonomic function in middle-aged and older adults: a...

This meta-analysis aimed to evaluate the effects of blood flow restriction training (BFRT) on heart rate variability (HRV), blood pressure, and heart rate in middle-aged and older adults. Following the PRISMA 2020 guidelines, randomized controlled trials examining the long-term effects of BFRT on HRV and blood pressure in adults aged 45 years or older were systematically searched in Web of Science, PubMed, Scopus, and Cochrane Library up to December 1, 2025. Meta-analyses were performed using the meta and metafor packages in RStudio. Subgroup analyses and meta-regression were conducted to explore potential sources of heterogeneity. Fourteen randomized controlled trials were included. BFRT significantly improved the root mean square of successive differences between adjacent NN intervals (RMSSD; SMD = 0.46, 95% CI [0.21, 0.71], p < 0.001, I² = 35.7%) and reduced systolic blood pressure (SBP; SMD = -0.67, 95% CI [ -1.05, -0.29], p < 0.0001, I² = 54.5%), diastolic blood pressure (DBP; SMD = -0.37, 95% CI [ -0.72, -0.02], p = 0.04, I² = 46.7%), and heart rate (HR; SMD = -0.30, 95% CI [-0.60, -0.01], p = 0.04, I² = 0%). No significant effects were observed for the standard deviation of normal-to-normal intervals (SDNN), low-frequency power (LF), high-frequency power (HF), low-frequency/high-frequency ratio (LF/HF), or percentage of adjacent normal-to-normal intervals differing by more than 50 ms (pNN50). Exploratory subgroup analyses suggested that participant characteristics and BFRT protocol variables may partly contribute to heterogeneity in blood pressure responses. Meta-regression indicated that intervention duration was associated with the SBP response, although this finding should be interpreted cautiously. BFRT may increase RMSSD and reduce blood pressure in middle-aged and older adults, with a potential modest reduction in heart rate. However, the certainty of evidence was limited, and subgroup findings related to training frequency and exercise modality should be considered hypothesis-generating only. Larger, well-powered randomized trials with complete sex reporting and direct comparisons of different BFRT modalities and intensities are needed to confirm these findings.