Daily Exercise Reduces Measures of Heart Rate and Blood Pressure Variability in Hypertensive Rats

Abstract

This study was designed to test the hypothesis that daily spontaneous running (DSR) reduces measures of heart rate and blood pressure variability in spontaneously hypertensive rats (SHR). After 8 weeks of DSR or sedentary control, rats were chronically instrumented with arterial catheters. Daily exercise reduced most measures of heart rate (HR) and blood pressure variability. Specifically DSR decreased heart rate, Low Frequency Power (LF: 0.19-0.61 Hz), and Low Frequency/High Frequency (HF: 1.2-2.5 Hz) ratio of HR. Furthermore, Total Power (TP), LF power, and LF/HF ratio of systolic blood pressure were reduced by daily spontaneous running. Finally, TP, LF and HF powers and LF/HF ratios of diastolic blood pressure were reduced by daily spontaneous running. These data demonstrate that daily exercise reduces sympathetic activity and possibly increases cardiac reserve in hypertensive animals.

Effects of angiotensin-converting enzyme inhibitor and exercise training on exercise capacity and skeletal muscle

“…Although it has been shown that exercise training lowers high blood pressure in SHR [38,39], the reduction in blood pressure was relatively small compared with the variation in resting blood pressure level [40]. Thus, to obtain a significant difference in resting blood pressure between sedentary and trained SHR, a larger number of rats than used in this study may be needed.…”

Cardiac Effects of Exercise Training in Hypertension

“…Voluntary activity wheel running has been shown to reduce sympathetic tone and also results in resting bradycardia and attenuation of the tachycardia response during progressive exercise in SHR [76,77]. is effect can, in part, be attributed to a signi�cantly reduced adrenergic tone controlling heart rate during exercise [78].…”

Linear and nonlinear measures of blood pressure variability: Increased chaos of blood pressure time series in patients with panic disorder

“…Recently, we found highly significant decreases in LF (0.19-61 Hz) of blood pressure time series in rats after endurance exercise training [DiCarlo et al, 2002]. The power in this band is blocked by clonidine and is related to sympathetic function [Blanc et al, 1991;Japundzic et al, 1990].…”

“…We have also shown that LF power of BP time series significantly decreases after endurance exercise training [DiCarlo et al, 2002]. Recently we also showed that the time series of cardiac output (CO) are chaotic in nature and that LLE of these time series also decreases significantly after endurance exercise training in rats, which may be due to a decrease in sympathetic activity [Yeragani et al, 2003a].…”

“…Such studies have resulted in valuable information about mechanisms of cardiovascular regulation in experimental animals as well [DiCarlo et al, 2002;Hagerman et al, 1996;Zweiner et al, 1996]. We have been investigating cardiovascular function in normal controls and patients with anxiety as well as depression owing to the increased incidence of cardiovascular mortality in these groups of patients [Carney et al, 1997;Frasure-Smith et al, 1995;Kawachi et al, 1994].…”