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Dynamic resistance training decreases sympathetic tone in hypertensive ovariectomized rats.

Shimojo GL, Palma RK, Brito JO, Sanches IC, Irigoyen MC, De Angelis K - Braz. J. Med. Biol. Res. (2015)

Bottom Line: Sympathetic tone was also lower in the trained group.Moreover, sympathetic tone was positively correlated with resting HR (r=0.7, P<0.05).This benefit may be associated with resting bradycardia and reduced cardiac sympathetic tone after training, which suggests potential benefits of resistance exercise for the management of hypertension after ovarian hormone deprivation.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiologia Translacional, Programa de Ciências da Reabilitação, Universidade Nove de Julho, São Paulo, SP, Brasil.

ABSTRACT
The aim of this study was to investigate the effects of resistance exercise training on hemodynamics and cardiac autonomic control in ovariectomized spontaneously hypertensive rats. Female rats were divided into 4 groups: sedentary control (SC), sedentary hypertensive (SH), sedentary hypertensive ovariectomized (SHO), and resistance-trained hypertensive ovariectomized (RTHO). Resistance exercise training was performed on a vertical ladder (5 days/week, 8 weeks) at 40-60% maximal load. Direct arterial pressure was recorded. Vagal and sympathetic tones were measured by heart rate (HR) responses to methylatropine (3 mg/kg, iv) and propranolol (4 mg/kg, iv). Ovariectomy resulted in additional increases in blood pressure in hypertensive rats and was associated with decreased vagal tone. Resistance exercise trained rats had lower mean arterial pressure than untrained rats (RTHO: 159±2.2 vs SHO: 177±3.4 mmHg), as well as resting bradycardia (RTHO: 332±9.0 vs SHO: 356±5 bpm). Sympathetic tone was also lower in the trained group. Moreover, sympathetic tone was positively correlated with resting HR (r=0.7, P<0.05). The additional arterial pressure increase in hypertensive rats caused by ovarian hormone deprivation was attenuated by moderate-intensity dynamic resistance training. This benefit may be associated with resting bradycardia and reduced cardiac sympathetic tone after training, which suggests potential benefits of resistance exercise for the management of hypertension after ovarian hormone deprivation.

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Hemodynamic and cardiac autonomic control in the studied groups. SC: sedentarycontrol; SH: sedentary hypertensive; SHO: sedentary hypertensive ovariectomized;RTHO: resistance-trained hypertensive ovariectomized. *P<0.05vs SC; #P<0.05 vs SH;+P<0.05 vs SHO (one-way ANOVA, followed byStudent-Newmann-Keuls test).
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f01: Hemodynamic and cardiac autonomic control in the studied groups. SC: sedentarycontrol; SH: sedentary hypertensive; SHO: sedentary hypertensive ovariectomized;RTHO: resistance-trained hypertensive ovariectomized. *P<0.05vs SC; #P<0.05 vs SH;+P<0.05 vs SHO (one-way ANOVA, followed byStudent-Newmann-Keuls test).

Mentions: Ovariectomized hypertensive rats had a higher MAP than non-ovariectomized hypertensiverats (SHO vs SH group). Rats that underwent resistance exercisetraining had a lower MAP relative to those in both the SH and SHO groups. Resistanceexercise training also resulted in resting bradycardia in the RTHO group (Figure 1).


Dynamic resistance training decreases sympathetic tone in hypertensive ovariectomized rats.

Shimojo GL, Palma RK, Brito JO, Sanches IC, Irigoyen MC, De Angelis K - Braz. J. Med. Biol. Res. (2015)

Hemodynamic and cardiac autonomic control in the studied groups. SC: sedentarycontrol; SH: sedentary hypertensive; SHO: sedentary hypertensive ovariectomized;RTHO: resistance-trained hypertensive ovariectomized. *P<0.05vs SC; #P<0.05 vs SH;+P<0.05 vs SHO (one-way ANOVA, followed byStudent-Newmann-Keuls test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470311&req=5

f01: Hemodynamic and cardiac autonomic control in the studied groups. SC: sedentarycontrol; SH: sedentary hypertensive; SHO: sedentary hypertensive ovariectomized;RTHO: resistance-trained hypertensive ovariectomized. *P<0.05vs SC; #P<0.05 vs SH;+P<0.05 vs SHO (one-way ANOVA, followed byStudent-Newmann-Keuls test).
Mentions: Ovariectomized hypertensive rats had a higher MAP than non-ovariectomized hypertensiverats (SHO vs SH group). Rats that underwent resistance exercisetraining had a lower MAP relative to those in both the SH and SHO groups. Resistanceexercise training also resulted in resting bradycardia in the RTHO group (Figure 1).

Bottom Line: Sympathetic tone was also lower in the trained group.Moreover, sympathetic tone was positively correlated with resting HR (r=0.7, P<0.05).This benefit may be associated with resting bradycardia and reduced cardiac sympathetic tone after training, which suggests potential benefits of resistance exercise for the management of hypertension after ovarian hormone deprivation.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiologia Translacional, Programa de Ciências da Reabilitação, Universidade Nove de Julho, São Paulo, SP, Brasil.

ABSTRACT
The aim of this study was to investigate the effects of resistance exercise training on hemodynamics and cardiac autonomic control in ovariectomized spontaneously hypertensive rats. Female rats were divided into 4 groups: sedentary control (SC), sedentary hypertensive (SH), sedentary hypertensive ovariectomized (SHO), and resistance-trained hypertensive ovariectomized (RTHO). Resistance exercise training was performed on a vertical ladder (5 days/week, 8 weeks) at 40-60% maximal load. Direct arterial pressure was recorded. Vagal and sympathetic tones were measured by heart rate (HR) responses to methylatropine (3 mg/kg, iv) and propranolol (4 mg/kg, iv). Ovariectomy resulted in additional increases in blood pressure in hypertensive rats and was associated with decreased vagal tone. Resistance exercise trained rats had lower mean arterial pressure than untrained rats (RTHO: 159±2.2 vs SHO: 177±3.4 mmHg), as well as resting bradycardia (RTHO: 332±9.0 vs SHO: 356±5 bpm). Sympathetic tone was also lower in the trained group. Moreover, sympathetic tone was positively correlated with resting HR (r=0.7, P<0.05). The additional arterial pressure increase in hypertensive rats caused by ovarian hormone deprivation was attenuated by moderate-intensity dynamic resistance training. This benefit may be associated with resting bradycardia and reduced cardiac sympathetic tone after training, which suggests potential benefits of resistance exercise for the management of hypertension after ovarian hormone deprivation.

Show MeSH
Related in: MedlinePlus