Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: lower body negative pressure

Sortuj według:

Ogranicz wyniki do:

Cardiovascular and neurohormonal responses to lower body negative pressure [LBNP]: effect of training and 3 day bed rest

100%

Gasiorowska A., Mikulski T., Smorawinski J., Kaciuba-Uscilko H., Cybulski G., Zieba A. W., Krzeminski K., Niewiadomski W., Nazar K.

Journal of Physiology and Pharmacology. Supplement

2006

tom 57

nr 10

85-100

Both intensive training and bed confinement impair orthostatic tolerance, however, moderate training may exert beneficial effect on cardiovascular adjustment to gravitational stimuli. It was hypothesized that moderate training attenuates effects of bed rest. To test this assumption 24 healthy male volunteers aged 20.8±0.9 yrs were subjected to 6° head down bed rest (HDBR) for 3 days before and after 6 weeks of moderate endurance training. Before and after HDBR graded LBNP tests (-15, -30, -50 mmHg) were performed. During these tests heart rate (HR), stroke volume (SV), blood pressure (BP), plasma catecholamines, ACTH, adrenomedullin, atrial natriuretic peptide, plasma renin activity (PRA) and hematocrit were determined. HDBR did not systematically influence LBNP tolerance up to -50 mmHg, but it enhanced rates of reduction of SV, cardiac output and systolic BP and increased elevations of HR and PRA. Training did not alter significantly effects of HDBR on LBNP-induced changes in HR, SV, CO and TPR but it attenuated decrease in systolic BP and diminished increases in plasma noradrenaline and PRA. In conclusion, training has negligible effect on the HDBR-induced changes in central hemodynamics during LBNP but may increase vascular sensitivity to some vasoconstricting factors.

Effect of 6-week endurance training on hemodynamic and neurohormonal responses to lower body negative pressure (LBNP) in healthy young men

80%

Nazar K., Gasiorowska A., Mikulski T., Cybulski G., Niewiadomski W., Smorawinski J., Krzeminski K., Ziemba A. W., Dorsz A., Kaciuba-Uscilko H.

Journal of Physiology and Pharmacology

2006

tom 57

nr 2

Endurance training is considered as a factor impairing orthostatic tolerance although an improvement and lack of effect have been also reported. The mechanisms of the changes and their relation to initial tolerance of orthostasis are not clear. In the present study, effect of moderate running training on hemodynamic and neurohormonal changes during LBNP, a laboratory test simulating orthostasis, was investigated in subjects with high (HT) and low (LT) tolerance of LBNP. Twenty four male, healthy subjects were submitted to graded LBNP (-15, -30 and -50 mmHg) before and after training. During each test heart rate (HR), stroke volume (SV) and blood pressure, plasma catecholamines, ACTH, adrenomedullin, atrial natriuretic peptide, and renin activity were determined. Basing on initial test, 13 subjects who withstood LBNP at -50 mmHg for 10 min were allocated into HT group and 11 subjects who earlier showed presyncopal symptoms to LT group. Training improved LBNP tolerance in six LT subjects. This was associated with attenuated rate of HR increase and SV decline (before training, at -30 mmHg DHR was 21 ± 4 beats/min and SV – -36± 8 ml while after training the respective values were 8 ± 4 beats/min and -11± 6 ml). No differences in hemodynamic response were found in HT subjects and those from LT group whose LBNP tolerance was unchanged. In neither group training affected neurohormonal changes except inhibition of plasma ACTH rise in subjects with improvement of LBNP tolerance. It is concluded that some subjects with low orthostatic tolerance may benefit from moderate training due to improvement of cardiac function regulation.

Ograniczanie wyników

1 Journal of Physiology and Pharmacology

1 Journal of Physiology and Pharmacology. Supplement

2 Cybulski G.

2 Gasiorowska A.

2 Kaciuba-Uscilko H.

2 Krzeminski K.

2 Mikulski T.

2 Nazar K.

2 Niewiadomski W.

2 Smorawinski J.

1 Dorsz A.

1 Zieba A. W.

1 Ziemba A. W.

2 2006

Wyniki wyszukiwania

Cardiovascular and neurohormonal responses to lower body negative pressure [LBNP]: effect of training and 3 day bed rest

Effect of 6-week endurance training on hemodynamic and neurohormonal responses to lower body negative pressure (LBNP) in healthy young men