Heart rate variability and blood pressure response to low intensity  endurance exercise training  plus blood flow restriction in individuals with mild hypertension

Background: Considering the lack of sufficient information, this study examined the effects of low- intensity endurance exercise training alone and with blood flow restriction (BFR) on blood pressure, electrocardiogram (ECG), and heart rate variability (HRV) in individuals with mild hypertension. Methods: 43 participants aged 50 – 65 years with mild hypertension were divided into three groups including; endurance exercise with BFR (Ex+ BFR) endurance exercise only (Ex), and a control group (Con) Exercise training was performed three times a week for ten weeks. Before and after the training program, HRV, blood pressure, resting heart rate, and heart rate recovery time were measured and analyzed. Results: In both Ex and Ex + BFR groups, RMSSD, SDSD, HF (nu), SD1, and the SD1/SD2 ratio significantly increased but, SD2 and the LF/HF ratio decreased vs. control group. Changes in the aforementioned parameters in Ex + BFR group than in Ex group. In comparison to Ex group, Ex + BFR group showed a greater reduction in the QRS interval (15% vs. 12%) and heart rate (7.9% vs. 6.3%) (P < 0.05). Both Ex and Ex+BFR groups experienced a significant decrease in heart rate recovery time and blood pressure (P < 0.001 vs. Con group), with no significant differences between them. Conclusion: Low- intensity endurance training combined with blood flow restriction not only had no negative impact on blood pressure, HRV, heart rate recovery, and ECG parameters, but in long term, it may have more positive impact compared to exercise alone in individuals with mild hypertension.