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Moderate exercise training reduces arterial chemoreceptor reflex drive in mild hypertension

100%

Izdebska E., Izdebski J., Cybulska I., Makowiecka-Ciesla M., Trzebski A.

Journal of Physiology and Pharmacology. Supplement

2006

tom 57

nr 11

93-102

The aim of our study was to check the responsiveness the chemoreceptor reflex in 28 young mildly hypertensive men (HTS), aged 18-32 years and 25 normotensive male subjects (NTS) aged 19-32 years, before and after 3-months dynamic exercise training. We tested the hypothesis that dynamic training reduces arterial chemoreceptor drive in mild hypertension. Circulatory response to 3-min hyperoxic inactivation of arterial chemoreceptors induced by 70% oxygen breathing was measured before and after training. Arterial blood pressure (BP) was recorded continuously by Finapres method, stroke volume and arm blood flow were registered by impedance reography, heart rate by ECG. Both groups were submitted to moderate 3-months dynamic exercise training. Before training the hyperoxic breathing caused in HTS a significant decrease in systolic BP by 6±1mmHg p<0.01, in diastolic BP by 2±0.6mmHg p<0.01, and in total peripheral vascular resistance (TPR) by 0.24±0.04 TPRU (p<0.01). After training hyperoxia augmented systolic BP by 2.64±1.9mmHg (NS), diastolic BP by 2±1mmHg p<0.05, and TPR by 0.043±0.05 TPRU (ANOVA). In NTS before training brief hyperoxia produced insignificant change in BP and TPR. In NTS after training hyperoxia increased systolic BP by 4.2 mm Hg±1.23 p<0.01 and diastolic BP by 3.1±0.6mmHg p<0.01 respectively and TPR by 0.053±0.02 TPRU. Our results confirm earlier finding on the enhanced arterial chemoreceptor reflex drive in mild human hypertension. We conclude that normalizing arterial blood pressure in subjects with mild hypertension which occurred after 3-months dynamical exercise training is due to attenuation of the sympathoexcitatory chemoreceptor reflex drive by exercise training. The mechanism of this effect requires further study.

Effects of moderate physical training on blood pressure variability and hemodynamic pattern in mildly hypertensive subjects

100%

Izdebska E., Cybulska I., Izdebski J., Makowiecka-Ciesla M., Trzebski A.

Journal of Physiology and Pharmacology

2004

tom 55

nr 4

The objective of our study was to compare the cardiovascular effects of moderate exercise training in heathy young (NTS, n=18, 22.9±0.44 years) and in hypertensive human subjects (HTS, n=30, 23±1.1). The VO2max did not significantly differ between groups. HTS of systolic blood pressure (SBP) 148±3.6 mmHg and diastolic blood pressure(DBP) 88±2.2mmHg, and NTS of SBP: 128.8 ± 4 mmHg and DBP: 72 ± 2.9 mmHg were submitted to moderate dynamic exercise training, at about 50% VO2max 3 times per week for one hour, over 3 months. VO2max was measured by Astrand's test. Arterial blood pressure was measured with Finapres technique, the stroke volume, cardiac output and arm blood flow were assessed by impedance reography. Variability of SBP and pulse interval values (PI) were estimated by computing the variance and power spectra according to FFT algorithm. After training period significant improvements in VO2max were observed in NTS- by 1.92 ±0.76 and in HTS by 3±0.68 ml/kg/min). In HTS significantly decreased: SBP by 19 ±2.9 mmHg, in DBP by 10.7±2 mmHg total peripheral resistance (TPR) by 0.28 ±0.05 TPR units. The pretraining value of low frequency component power spectra SBP (LFSBP) was significantly greater in HTS, compared to NTS. PI variance was lower in HTS, compared to NTS. After physical training, in HTS PI variance increased suggesting a decrease in frequency modulated sympathetic activity and increase in vagal modulation of heart rate in mild hypertension. A major finding of the study is the significant decrease of resting low frequency component SBP power spectrum after training in HTS. The value of LFSBP in trained hypertensive subjects normalized to the resting level of LFSBP in NTS. Our findings suggest that antihypertensive hemodynamic effects of moderate dynamic physical training are associated with readjustment of the autonomic cardiovascular control system.

Ograniczanie wyników

1 Journal of Physiology and Pharmacology

1 Journal of Physiology and Pharmacology. Supplement

2 Cybulska I.

2 Izdebska E.

2 Izdebski J.

2 Makowiecka-Ciesla M.

2 Trzebski A.

1 2006

1 2004

Wyniki wyszukiwania

Moderate exercise training reduces arterial chemoreceptor reflex drive in mild hypertension

Effects of moderate physical training on blood pressure variability and hemodynamic pattern in mildly hypertensive subjects