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Descripción
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| INTRODUCTION During submaximal steady-state (SS) exercise the adrenaline and noradrenaline concentration are supposed to increase continuously 1, 2, being an indicator of the sympathetic activation 6. Differents studies have shown relations between sympathetic and parasympathetic activity and the different spectral components of HRV 6. The aim of this study was to compare the catecholamines and HRV response at the MLSS in cycling, to differentiate the nervous activity during exercise. MATERIAL AND METHODS Twelve amateur cyclists participated in the study (21 ± 2.6 years; 179.8 ± 7.5 cm; 72.2 ± 9 Kg). Each subject performed an incremental test (25 W o min-1) until exhaustion on a cicloergometer, and two 30 minutes constant load tests to determine the MLSS 3, 4 at an intensity around the mean point of ventilatory thresholds (VT). Expired air was analyzed with a Jaeger Oxycon Pro. Arterialized venous blood samples were obtained at 0, 10, 20 and 30 minutes during the SS tests. Lactate concentration [L-] and catecholamines concentration were determined. The heart rate (HR) was obtained from a Polar HR monitor and HRV was measured using HRV analysis software. A one way ANOVA was used to compare the response of the variables in 0, 10, 20 and 30 minutes and Pearson correlation analysis was used to set the relationships between variables. The significant level was set at <0.05. RESULTS The VO2 during MLSS was 4225.17±414.39 mL/min (58.82±4.67 mL/min/kg) and 81.84±7.02 %VO2max. The workload was 279±28 W. The main significant correlations were obtained between [L-] and noradrenaline concentration [Nor] and HR (r=0.855 and r=0.835 respectively), [Nor] and HR (r=0.852), high frequency (HF) and low frequency (LF) and very high-frequency (VHF) (r=0.894 and r=0.839 respectively). There were not significant correlations between hormons concentration and HRV variables. Significant differences were found between 0 minute and 10, 20 and 30 minutes in almost all variables along the MLSS (p<0.05). Hidrogen ion concentration [H+], [L-] and adrenaline concentration were stable (10, 20 and 30 minutes), while HR and [Nor] increased from 10 minute to 30 minute (p<0.05). LF, HF and VHF decreased from 10 minute to 30 minute (p<0.05). DISCUSION HR and [Nor] did not stay stable during the MLSS test, due to the “cardiovascular drift” and the increase in sympathetic nervous system activity 2, 5. However, our results sugest there is no relation between catecholamines and HRV during the MLSS. Thus, the use of HRV is not clear to differentiate the nervous activity during MLSS6. References. 1. Urhausen, A, et al. Eur J Appl Physiol Occup Physiol (1994); 69: 16-20. 2. Rostrup, M, et al. Clin Physiol (1998); 18: 109-15. 3. Laplaud, D, et al. Eur J Appl Physiol (2006); 96: 446-52. 4. Beneke, R. Eur J Appl Physiol (2003); 89: 95-9. 5. Baron, B, et al. Int J Sports Med (2003); 24: 582-7. 6. Breuer, HW, et al. Br Heart J (1993); 70: 144-9. | |
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Internacional
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Si |
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Nombre congreso
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13th Annual Congress of the European College of Sport Science |
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Tipo de participación
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960 |
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Lugar del congreso
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Estoril (Portugal) |
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Revisores
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No |
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ISBN o ISSN
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978-972-735-156-5 |
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DOI
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Fecha inicio congreso
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09/07/2008 |
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Fecha fin congreso
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12/07/2008 |
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Desde la página
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18 |
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Hasta la página
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18 |
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Título de las actas
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13th Annual Congress of the European College of Sport Science. Book of Abstracts. Digital version |