Reduction of blood pressure and heart rate responses to isometric exercise by isometric strength training

1979 ◽  
Vol 43 (2) ◽  
pp. 398
1992 ◽  
Vol 72 (3) ◽  
pp. 1039-1043 ◽  
Author(s):  
V. K. Somers ◽  
K. C. Leo ◽  
R. Shields ◽  
M. Clary ◽  
A. L. Mark

Recent evidence indicates that muscle ischemia and activation of the muscle chemoreflex are the principal stimuli to sympathetic nerve activity (SNA) during isometric exercise. We postulated that physical training would decrease muscle chemoreflex stimulation during isometric exercise and thereby attenuate the SNA response to exercise. We investigated the effects of 6 wk of unilateral handgrip endurance training on the responses to isometric handgrip (IHG: 33% of maximal voluntary contraction maintained for 2 min). In eight normal subjects the right arm underwent exercise training and the left arm sham training. We measured muscle SNA (peroneal nerve), heart rate, and blood pressure during IHG before vs. after endurance training (right arm) and sham training (left arm). Maximum work to fatigue (an index of training efficacy) was increased by 1,146% in the endurance-trained arm and by only 40% in the sham-trained arm. During isometric exercise of the right arm, SNA increased by 111 +/- 27% (SE) before training and by only 38 +/- 9% after training (P less than 0.05). Endurance training did not significantly affect the heart rate and blood pressure responses to IHG. We also measured the SNA response to 2 min of forearm ischemia after IHG in five subjects. Endurance training also attenuated the SNA response to postexercise forearm ischemia (P = 0.057). Sham training did not significantly affect the SNA responses to IHG or forearm ischemia. We conclude that endurance training decreases muscle chemoreflex stimulation during isometric exercise and thereby attenuates the sympathetic nerve response to IHG.


2008 ◽  
Vol 26 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Jonathan D. Wiles ◽  
Simon R. Allum ◽  
Damian A. Coleman ◽  
Ian L. Swaine

1974 ◽  
Vol 47 (3) ◽  
pp. 249-257 ◽  
Author(s):  
D. F. Marcus ◽  
H. F. Edelhauser ◽  
M. G. Maksud ◽  
R. L. Wiley

1. Normal subjects performed fatiguing static hand-grip contraction at tensions of 20% and 55% of their maximum voluntary contraction (MVC). Intraocular pressure (IOP) was measured by applanation tonometry before, during and after the isometric exercise. Forearm blood samples were taken from the antecubital vein in both the exercised and non-exercised arm before and 2 min post-exercise for measurement of plasma lactate, osmolality, Pv,o2, Pv,co2 and pH. 2. During hand grip the heart rate and blood pressure increased significantly, whereas the IOP remained unchanged from control in both the 20% and 55% MVC experiments. 3. In the recovery period heart rate and blood pressure returned to control values within 3 min and the IOP decreased significantly from control in both the 20% and 55% MVC experiments. 4. When an occlusion cuff was inflated on the exercising arm just before release of the 55% MVC grip, the decreased IOP could be delayed until the cuff was released. 5. Post-exercise blood samples showed elevated lactate concentrations and Pv,o2 and decreased pH in the exercised arm; however, the values remained unchanged in the non-exercised arm. The decreased IOP after exercise may be related to an increased blood lactate concentration.


2018 ◽  
Vol 0 (Avance Online) ◽  
Author(s):  
R Miguel-dos-Santos ◽  
JF Santos ◽  
FN Macedo ◽  
MB Almeida ◽  
VJ Santana-Filho ◽  
...  

Resumo Objetivo: Avaliar os efeitos do treinamento de força sobre as hipertrofias renal e cardíaca induzida pela hipertensão renovascular em ratos. Método: Dezoito ratos Wistar foram divididos em três grupos: Sham, hipertenso (2K1C) e hipertenso treinado (2K1C-TR). Os animais foram induzidos a hipertensão renovascular através da ligadura da artéria renal esquerda. O treinamento de força foi iniciado quatro semanas após a indução da hipertensão renovascular, teve duração de 12 semanas e foi realizado a 70% de uma repetição máxima. Ao final foi medida pressão arterial, frequência cardíaca e parâmetros das hipertrofias renal e cardíaca. Resultados: O treinamento de força promoveu a redução da frequência cardíaca (p=0.0025) e da pressão arterial (p=0.01). Além disso, o treinamento diminuiu as massas absolutas do rim (p=0.0001) e coração (p=0.006), e os índices de hipertrofias renal e cardíaca, tanto normalizado pela massa corporal dos animais (p=0.0001 e p=0.001, respectivamente) como normalizado pelo comprimento da tíbia (p=0.004 e p=0.0004, respectivamente). Conclusão: O treinamento de força tem efeitos benéficos na hipertensão renovascular em animais, sendo capaz de reduzir a pressão arterial e a frequência cardíaca, além de atenuar o desenvolvimento das hipertrofias renal e cardíaca em ratos com hipertensão renovascular. Resumen Objetivo: Evaluar los efectos del entrenamiento de fuerza sobre las hipertrofias renal y cardíaca inducidas por la hipertensión renovascular en ratas. Método: Dieciocho ratas se dividieron en tres grupos: simulado, hipertenso (2R1C) e hipertenso entrenado (2R1C-TR). Los animales fueron inducidos a la hipertensión renovascular a través de la ligadura de la arteria renal izquierda. El entrenamiento de fuerza se inició cuatro semanas después de la inducción de la hipertensión renovascular, duró 12 semanas y se realizó al 70% de una repetición máxima. Al final se midió la presión arterial, la frecuencia cardiaca y los parámetros de las hipertrofias renal y cardíaca. Resultados: El entrenamiento de fuerza promovió la reducción de la frecuencia cardíaca (p=0.0025) y la presión arterial (p=0.01). Además el entrenamiento disminuyó las masas absolutas de los riñones (p=0.0001) y el corazón (p=0.006), y los índices de hipertrofias renal y cardíaca, tanto normalizado por la masa corporal de los animales (p=0.0001 e p=0.001, respectivamente) como normalizado por la longitud de la tibia (p=0.004 e p=0.0004, respectivamente). Conclusión: El entrenamiento de fuerza tiene efectos beneficiosos en la hipertensión renovascular en animales, siendo capaz de reducir la presión arterial y la frecuencia cardíaca, además de atenuar el desarrollo de las hipertrofias renal y cardíaca en ratas con hipertensión renovascular. Abstract Objective: To evaluate the effects of strength training on renal and cardiac hypertrophy induced by the renovascular hypertension in rats. Method: Eighteen male rats were divided into three groups: sham, hypertensive (2K1C) and trained hypertensive (2K1C-TR). The animals were induced to renovascular hypertension through ligation of the left renal artery. Strength training was initiated four weeks after the induction of renovascular hypertension, had the duration of 12 weeks and was performed at 70% of one maximum repetition. At the end, it was measured blood pressure, heart rate and parameters of renal and cardiac hypertrophies. Results: Strength training promoted reduction in heart rate (p=0.0025) and blood pressure (p=0.01). In addition, training decreased the absolute masses of the kidney (p=0.0001) and heart (p=0.006), and the indexes of renal and cardiac hypertrophy, both normalized by the body mass of the animals (p=0.0001 e p=0.001, respectively) and by the length of the tibia (p=0.004 e p=0.0004, respectively). Conclusion: Strength training has beneficial effects on renovascular hypertension in animals, being able to reduce blood pressure and heart rate, attenuating the development of renal and cardiac hypertrophies in rats with renovascular hypertension.


1981 ◽  
Vol 60 (2) ◽  
pp. 139-143 ◽  
Author(s):  
S. J. Watt ◽  
R. D. Thomas ◽  
P. W. Belfield ◽  
P. W. Goldstraw ◽  
S. H. Taylor

1. The effects of single oral doses of various sympatholytic drugs on the heart rate and blood pressure increases during isometric handgrip contraction were studied in six healthy subjects. 2. Bethanidine reduced both the systolic and diastolic increases in pressure. Clonidine reduced the systolic but not the diastolic increase. Oxprenolol alone or in combination with phentolamine or phenyoxybenzamine failed to influence the pressor response. 3. The increase in systemic blood pressure associated with sustained contraction of voluntary muscle appears to be relatively resistant to acute sympathetic adrenoreceptor blockade in man.


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