Heart Rate Variability Dynamics after Resistance Training with Blood Flow Restriction in Individuals with Metabolic Syndrome

We know that autonomic disfunction is due to metabolic pathologies. The same time, physical activity has beneficial effects on metabolic health and heart rate variability (HRV). But there is no consensus about the effect of trainings with weights on HRV in the scientific literature. Purpose: To asses the impact of low-intensity power trainings with blood flow restrictions on HRV of men with metabolic syndrome (MS). Materials and methods: Influence of different weight training modes on 60 men with MS was analyzed. The participants were divided into three groups: low-load resistance training with blood flow restriction (LLBFR; n = 20), high-intensity resistance training without blood flow restriction (HI; n = 20), low-load resistance training without blood flow restriction (LL; n = 20). Trainings were conducted twice a week for 12 weeks. Time and frequency indicators were assessed before and after the investigation. Results: After the investigation, there were an increase in SDNN for the LLBFR group (p = 0.000; Cohen’s d = 0.69), for the HI group (p = 0.000; Cohen’s d = 0.83), for the LL group (p = 0.016; Cohen’s d = 0.22), an increase in RMSSD for the LLBFR group (p = 0.000; Cohen’s d = 0.67), for the HI group (p = 0.000; Cohen’s d = 0.87), for the LL group (p = 0.027; Cohen’s d = 0.26), as well as an increase in pNN50 for the LLBFR group (p = 0.000; Cohen’s d = 0.58), for the HI group (p = 0.000; Cohen’s d = 0.53), for the LL group (p = 0.079; Cohen’s d = 0.14). Statistically significant changes (p ˂ 0.05) were also observed for the frequency parameters of HRV for the LLBFR and HI groups. Conclusions: Resistance training, including in combination with blood flow restriction, has a positive effect on HRV in men with MS.