Heart Rate Variability After Blood Flow Restriction Resistance Exercise and Traditional Resistance Exercise in Trained Men and Women

Perlet, MR, Mendonça, LI, Hosick, PA, Licameli, N, and Matthews, EL. Heart rate variability after blood flow restriction resistance exercise and traditional resistance exercise in trained men and women. J Strength Cond Res XX(X): 000-000, 2025-Autonomic nervous system responses are attenuated after blood flow restriction (BFR) resistance exercise vs. traditional resistance exercise (TRE) in men, but women's responses are unknown. The purpose of this investigation is to compare the effects of a single BFR vs. TRE session on HRV. Thirty-nine adults (M=20, W=19, age: 23±4yrs, body mass: 72.3±13.2kg, height: 169±9cm) participated in the study. Barbell back squat 1 repetition maximum (1RM) testing was performed followed by 2 randomized and counterbalanced exercise visits ≥48 hours apart (BFR: 4 sets, 30-15-15-15 repetitions, 30% 1RM, 60 s rest; TRE: 4 sets × 10 repetitions, 70% 1RM, 60 s rest). Pre- and postexercise resting electrocardiograms were analyzed using heart rate variability (HRV) normalized units for low frequency (LF), high frequency (HF), and LF/HF. Two-way repeated measures analysis of variances with sex as a between-subjects effect were analyzed (alpha p < 0.05). Both LF and HF displayed interaction effects (both p < 0.05) with no effect or interaction with sex (all p > 0.05). Post hoc testing found that LF increased and HF decreased postexercise, but with greater effects in the TRE condition (all p < 0.05). Low frequency/HF also increased postexercise, and there was a sex by time interaction (all p < 0.05). Post hoc testing found greater increases in LF/HF postexercise in men than in women (p < 0.05) across exercise conditions. Both TRE and BFR increased sympathetic activity and decreased parasympathetic activity HRV indices, and the changes were attenuated for BFR in both sexes. However, men have a greater shift toward sympathetic dominance independent of exercise type. These changes in HRV indices may have beneficial applications for exercise training/recovery when trying to reduce autonomic stress.