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.
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