The Effect of Physical Resistance Training on Baroreflex Sensitivity of Hypertensive Rats

Abstract

Background:Baroreceptors act as regulators of blood pressure (BP); however, its sensitivity is impaired in hypertensive patients. Among the recommendations for BP reduction, exercise training has become an important adjuvant therapy in this population. However, there are many doubts about the effects of resistance exercise training in this population.Objective:To evaluate the effect of resistance exercise training on BP and baroreceptor sensitivity in spontaneously hypertensive rats (SHR).Method:Rats SHR (n = 16) and Wistar (n = 16) at 8 weeks of age, at the beginning of the experiment, were randomly divided into 4 groups: sedentary control (CS, n = 8); trained control (CT, n = 8); sedentary SHR (HS, n = 8) and trained SHR (HT, n = 8). Resistance exercise training was performed in a stairmaster-type equipment (1.1 × 0.18 m, 2 cm between the steps, 80° incline) with weights attached to their tails, (5 days/week, 8 weeks). Baroreceptor reflex control of heart rate (HR) was tested by loading/unloading of baroreceptors with phenylephrine and sodium nitroprusside.Results:Resistance exercise training increased the soleus muscle mass in SHR when compared to HS (HS 0.027 ± 0.002 g/mm and HT 0.056 ± 0.003 g/mm). Resistance exercise training did not alter BP. On the other hand, in relation to baroreflex sensitivity, bradycardic response was improved in the TH group when compared to HS (HS -1.3 ± 0.1 bpm/mmHg and HT -2.6 ± 0.2 bpm/mmHg) although tachycardia response was not altered by resistance exercise (CS -3.3 ± 0.2 bpm/mmHg, CT -3.3 ± 0.1 bpm/mmHg, HS -1.47 ± 0.06 bpm/mmHg and HT -1.6 ± 0.1 bpm/mmHg).Conclusion:Resistance exercise training was able to promote improvements on baroreflex sensitivity of SHR rats, through the improvement of bradycardic response, despite not having reduced BP.

Investigation and Comparison of the Effects of Eight Weeks of Resistance and Endurance Training with Vitamin D3 Supplementation on Blood Pressure, Resting Heart Rate, and Body Composition in Obese Hypertensive Middle-Aged Men

“…In the current study, a significant decrease in the systolic and diastolic blood pressure was observed after 8 weeks of resistance and endurance training with vitamin D 3 supplementation, whereas this difference not observed in the C and D groups. These results are similar to those reported by Trevizani (5,6). The reasons for this inconsistency may be related to the training protocol, training intensity, and subject's status; the above studies were done in type 2 diabetic animals whereas the participants in this study were obese hypertensive middle-aged men.…”

“…For example, Ghardashi Afousi et al (2016) reported no significant changes in the systolic and diastolic blood pressure of patients with type 2 diabetes and hypertension following 10 weeks of periodic aerobic training (5). In this respect, Gomes et al (2017) have shown that 8 weeks of resistance training produced no significant changes in the blood pressure in hypertensive rats (6). However, Trevizani et al (2017) have reported that 4 weeks (12 sessions) of resistance training reduces blood pressure significantly (7), and Grace et al (2017) have also reported similar results following 6 weeks of aerobic training (8).…”

Muscle hypertrophy and ladder‐based resistance training for rodents: A systematic review and meta‐analysis

“…Nineteen articles published data about the maximum load‐carrying tests protocol (Antonio‐Santos et al., 2016; Carbone et al., 2017; Chi et al., 2020; Deus et al., 2012; Domingos et al., 2012; Gil & Kim, 2015; Gomes, Borges, Rossi, Moura, & Medeiros, 2017; Grans et al., 2014; Hornberger & Farrar, 2004; Kwon et al, 2018; Lim et al, 2018; Mônico‐Neto et al, 2015; Neves et al, 2019; Padilha et al, 2017; Padilha et al., 2019; Perrilhão et al, 2019; Prestes et al, 2009; Souza et al., 2014; Souza et al, 2017). LRT presented a positive effect on the maximum load‐carrying capacity (16 studies, SMD 12.37, 95% CI [9.36, 15.37], p < .00001, I 2 = 90%, Figure 11).…”

Cardiovascular Adaptations Induced by Resistance Training in Animal Models

“…Furthermore , RT was associated to better metalloproteinases-2 activity in the left ventricle, systolic and diastolic BP in high-fat fed rats and to prevents obesity-induced cardiovascular disorders, including an increase in mean arterial pressure, sympathetic modulation and impaired baroreflex sensitivity 72 , 73 . In addition, this model of RT has been shown to be effective in cardiac autonomic adaptations in healthy and SHR rats 74 , 75 , to prevent chronic elevation in systolic BP in severe hypertension 76 and to improves hemodynamic status in diabetic ovariectomized rats 77 .…”