Dynamic resistance training improves cardiovascular autonomic variability in male hypertensive rats

Abstract

The dynamic resistance training (DRT) has been the focus of recent researches; however, few studies evaluated the effects of DRT on hemodynamics of hypertensive subjects. The objective of this study was to evaluate the effects of DRT on blood pressure (BP) and cardiovascular autonomic modulation in spontaneously hypertensive rats. Thus, we used 16 adult males SHR, divided into two groups (n = 8/group): sedentary (SM) and trained (TM). Maximal exercise testing was conducted before and after the training period. The DRT, in moderate intensity (40–60% of the maximal load), was performed in a ladder adapted for rats per 8 weeks. After this period, blood glucose and triglyceride were measured and catheter was inserted in the carotid artery for direct measurement of BP (WINDAQ, 2 KHz). BP and heart rate variability were evaluated in time and frequency domains. At the end of the protocol, there was an improvement in physical capacity in the TM group (TM: 737±39 vs. SM: 476±50 g). Moreover, there were no differences in the weight of left ventricle and soleus muscle; however, the TM group showed an increase in plantar muscle (0.26±0.01 g) when compared to SM group (0.20±0.02 g). There was no difference in heart rate (TM: 350±8 vs. SM: 366±10 bpm) and blood glucose (TM: 88±3 vs. SM: 85±2 mg/dl); however, TM group showed reduced blood triglycerides values (TM: 110±7 vs. SM: 133±4 mg/dl). DTR did not induced reduction in mean, systolic and diastolic BP (mean BP, TM: 186±4 vs. TS: 185±9 mmHg). Despite that, DRT improved cardiac vagal modulation demonstrated by the increase in SD‐IP (TM: 6.61±1.31 vs. SM: 3.68±0.32 ms) and RMSSD (TM: 3.95±0.30 vs. SM: 3.02±0.25 ms). A reduction in BP variance (TM: 33±3 vs. SM: 66±4 mmHg2) and vascular sympathetic modulation (LF‐BP, TM: 6±2 vs. SM: 12±1 mmHg2) were observed in trained group. Additionally, DRT induced an improvement on spontaneous baroreflex (TM: 0.39±0.04 vs. SM: 0.22±0.01 ms/mmHg). We conclude that moderate intensity DRT in male SHR unchanged resting BP, but induced improvement on cardiovascular autonomic variability. These results suggesting a positive role of this approach, associated with aerobic exercise training, on hypertension management.Support or Funding InformationFAPESP 2015/10329‐5, 2015/11223‐6, UNINOVE.