scholarly journals Exercise training bradycardia is largely explained by reduced intrinsic heart rate

2016 ◽  
Vol 222 ◽  
pp. 213-216 ◽  
Author(s):  
Samira Bahrainy ◽  
Wayne C. Levy ◽  
Janet M. Busey ◽  
James H. Caldwell ◽  
John R. Stratton
Keyword(s):  
Heart Rate ◽  
Exercise Training ◽  
Intrinsic Heart Rate

Exercise training changes autonomic cardiovascular balance in mice

2004 ◽  
Vol 96 (6) ◽  
pp. 2174-2178 ◽  
Author(s):  
K. De Angelis ◽  
R. B. Wichi ◽  
W. R. A. Jesus ◽  
E. D. Moreira ◽  
M. Morris ◽  
...  
Keyword(s):  
Heart Rate ◽  
Exercise Training ◽  
Arterial Pressure ◽  
Baroreflex Sensitivity ◽  
Dynamic Exercise ◽  
Autonomic Control ◽  
Trained Group ◽  
Intrinsic Heart Rate ◽  
Exercise Response ◽  
Training Protocol

Experiments were performed to investigate the influence of exercise training on cardiovascular function in mice. Heart rate, arterial pressure, baroreflex sensitivity, and autonomic control of heart rate were measured in conscious, unrestrained male C57/6J sedentary ( n = 8) and trained mice ( n = 8). The exercise training protocol used a treadmill (1 h/day; 5 days/wk for 4 wk). Baroreflex sensitivity was evaluated by the tachycardic and bradycardic responses induced by sodium nitroprusside and phenylephrine, respectively. Autonomic control of heart rate and intrinsic heart rate were determined by use of methylatropine and propranolol. Resting bradycardia was observed in trained mice compared with sedentary animals [485 ± 9 vs. 612 ± 5 beats/min (bpm)], whereas mean arterial pressure was not different between the groups (106 ± 2 vs. 108 ± 3 mmHg). Baroreflex-mediated tachycardia was significantly enhanced in the trained group (6.97 ± 0.97 vs. 1.6 ± 0.21 bpm/mmHg, trained vs. sedentary), whereas baroreflex-mediated bradycardia was not altered by training. The tachycardia induced by methylatropine was significantly increased in trained animals (139 ± 12 vs. 40 ± 9 bpm, trained vs. sedentary), whereas the propranolol effect was significantly reduced in the trained group (49 ± 11 vs. 97 ± 11 bpm, trained vs. sedentary). Intrinsic heart rate was similar between groups. In conclusion, dynamic exercise training in mice induced a resting bradycardia and an improvement in baroreflex-mediated tachycardia. These changes are likely related to an increased vagal and decreased sympathetic tone, similar to the exercise response observed in humans.

Exercise training reduces the sympathetic component of the blood pressure-heart rate baroreflex in man

1992 ◽  
Vol 2 (4) ◽  
pp. 292
Author(s):  
B A Kingwell ◽  
A M Dart ◽  
G L Jennings ◽  
P I Korner
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Exercise Training

Effect of exercise training on heart rate variability in healthy older adults

1999 ◽  
Vol 138 (3) ◽  
pp. 567-576 ◽  
Author(s):  
Phyllis K. Stein ◽  
Ali A. Ehsani ◽  
Peter P. Domitrovich ◽  
Robert E. Kleiger ◽  
Jeffrey N. Rottman
Keyword(s):  
Older Adults ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Training ◽  
Healthy Older Adults

Influence of cardiac innervation on intrinsic heart rate in dogs

1990 ◽  
Vol 258 (4) ◽  
pp. H1132-H1137 ◽  
Author(s):  
J. M. Evans ◽  
D. C. Randall ◽  
J. N. Funk ◽  
C. F. Knapp
Keyword(s):  
Heart Rate ◽  
Intrinsic Rate ◽  
Conscious State ◽  
Autonomic Innervation ◽  
Autonomic Activity ◽  
Cardiac Innervation ◽  
Cardiac Denervation ◽  
Ganglionic Blockade ◽  
Intrinsic Heart Rate

Intrinsic heart rate is defined as the rate at which the heart beats when all cardiac neural and hormonal inputs are removed. We determined the effect of prevailing autonomic innervation of the heart on the intrinsic heart rate in chronically maintained, sedated, normally innervated dogs (n = 14), and in 14 other dogs that had previously (greater than 12 day) undergone complete surgical cardiac denervation. Intrinsic rate was determined in both groups using the following two procedures: 1) pharmacological effector blockade; and 2) pharmacological ganglionic blockade. The intrinsic rate determined by effector blockade was 142.9 +/- 7.2 (SE) beats/min in the dogs with intact cardiac innervation. When the same treatment was given after total surgical cardiac denervation, intrinsic rate was 97.9 +/- 4.8 beats/min. Intrinsic heart rate was significantly (P less than 0.05) lower in surgically denervated dogs. Ganglionic blockade in surgically denervated animals yielded an intrinsic rate of 90.0 +/- 8.5 beats/min, which was again significantly lower than the corresponding value of 128.4 +/- 5.5 beats/min in normal dogs. There was no difference in the intrinsic heart rate as determined by effector vs. ganglionic blockade in either group of dogs. An additional six dogs were subjected to selective surgical sinoatrial nodal parasympathectomy; their intrinsic rate (effector blockade) in the conscious state was 115.8 +/- 4.3 beats/min; this was significantly lower than the corresponding value for normal dogs and significantly greater than in dogs subject to total surgical cardiac denervation. The lower rate observed in the totally denervated and selectively denervated dogs after effector and/or ganglionic blockades implies that intrinsic heart rate depends on the level or nature of prevailing autonomic activity.

Vagal function impairment after exercise training

1992 ◽  
Vol 72 (5) ◽  
pp. 1749-1753 ◽  
Author(s):  
C. E. Negrao ◽  
E. D. Moreira ◽  
M. C. Santos ◽  
V. M. Farah ◽  
E. M. Krieger
Keyword(s):  
Heart Rate ◽  
Electrical Stimulation ◽  
Exercise Training ◽  
Marked Reduction ◽  
Resting Heart Rate ◽  
Pacemaker Cells ◽  
Function Impairment ◽  
Stimulation Of ◽  
Vagal Function

The present investigation was undertaken to evaluate the vagal function of trained (T) and sedentary (S) rats by use of different approaches in the same animal. After 13 wk of exercise training (treadmill for 1 h 5 times/wk at 26.8 m/min and 15% grade), T rats had a resting heart rate (HR) slightly but significantly lower than S rats (299 +/- 3 vs. 308 +/- 3 beats/min). T rats had marked reduction of the intrinsic HR (329 +/- 4 vs. 369 +/- 5 beats/min) after blockade by methylatropine and propranolol. They also exhibited depressed vagal and sympathetic tonus. Baroreflex bradycardia (phenylephrine injections) was reduced, bradycardic responses produced by electrical stimulation of the vagus were depressed, and responses to methacholine injection were decreased in T rats. Therefore several evidences of vagal function impairment were observed in T rats. The resting bradycardia after exercise training is more likely to be dependent on alterations of the pacemaker cells, inasmuch as the intrinsic HR was markedly reduced.

scholarly journals Improvement of heart rate variability after exercise training and its predictors in COPD

2011 ◽  
Vol 105 (7) ◽  
pp. 1054-1062 ◽  
Author(s):  
Carlos Augusto Camillo ◽  
Viviane de Moraes Laburu ◽  
Nicole Soriano Gonçalves ◽  
Vinícius Cavalheri ◽  
Fernanda Priore Tomasi ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Training

scholarly journals Increase in the Heart Rate Variability with Deep Breathing in Diabetic Patients after 12-Month Exercise Training

2010 ◽  
Vol 220 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Bhagyalakshmi Sridhar ◽  
Nagaraja Haleagrahara ◽  
Ramesh Bhat ◽  
Anupama Bangra Kulur ◽  
Sridhar Avabratha ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Exercise Training ◽  
Diabetic Patients ◽  
Deep Breathing
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