Autonomic control of the cardiovascular system during acclimatization to high altitude: effects of sildenafil

Cornolo, Jérémy; Mollard, Pascal; Brugniaux, Julien V.; Robach, Paul; Richalet, Jean‐Paul

doi:10.1152/japplphysiol.00239.2004

Cited by 66 publications

(55 citation statements)

References 32 publications

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“…The increase in the ratio is believed to imply that the sympathetic system is dominant compared to the parasympathetic. Similar results were obtained by Cornolo et al [ 91 ] who reported that exposure to an altitude of 4,350 m for 1-2 days reduced power in the highfrequency band but increased low-frequency power, thereby increasing the low to high frequency ratio. From this they concluded that acute exposure to hypoxia is associated with decreased parasympathetic and increased sympathetic tone.…”

Section: Heart Rate Variabilitysupporting

confidence: 89%

Autonomic Nervous System

2013

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Section: Heart Rate Variabilitysupporting

confidence: 89%

Autonomic Nervous System

2013

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“…Analyses showed an increase in the LH/HF ratio during acclimatization (Sevre et al, 2001). Since HF power is assumed to be a marker of parasympathetic activity and LF power to be a combination of both parasympathetic and sympathetic tonic activity, it has been concluded that the sympathetic tone is less reduced than the parasympathetic control of HR upon high-altitude exposure (Sevre et al, 2001;Cornolo et al, 2004).…”

Section: Cardiovascular Responsementioning

confidence: 99%

Acclimatization to chronic intermittent hypoxia in mine workers: a challenge to mountain medicine in Chile

Farías

Jiménez²,

Osorio³

et al. 2013

Biol. Res.

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In the past two decades, Chile has developed intense mining activity in the Andes mountain range, whose altitude is over 4,000 meters above sea level. It is estimated that a workforce population of over 55,000 is exposed to high altitude hypobaric hypoxia. The miners work under shift systems which vary from 4 to 20 days at the worksite followed by rest days at sea level, in a cycle repeated for several years. This Chronic Intermittent Hypoxia (CIH) constitutes an unusual condition for workers involving a series of changes at the physiological, cellular and molecular levels attempting to compensate for the decrease in the environmental partial pressure of oxygen (PO 2 ). The mine worker must become acclimatized to CIH, and consequently undergoes an acute acclimatization process when he reaches the worksite and an acute reverse process when he reaches sea level. We have observed that after a period of 3 to 8 years of CIH exposure workers acclimatize well, and evidence from our studies and those of others indicates that CIH induces acute and chronic multisystem adjustments which are eff ective in off setting the reduced availability of oxygen at high altitudes. The aims of this review are to summarize fi ndings of the physiological responses to CIH exposure, highlighting outstanding issues in the fi eld.

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“…12 Preliminary studies measuring HRV during acute hypobaric hypoxia exposure reported a reduction in HRV by means of a decrease in total spectral power. 13,14 These studies demonstrated a change in the sympathetic---parasympathetic balance, in that the relative sympathetic tone increases along with a decrease in parasympathetic tone. A relationship between changes in VO 2 max and HRV alterations during acute hypobaric hypoxia has also been observed, with a decrease in the power of the high (HF) and low frequency (LF) bands and an increase in the LF/HF ratio.…”

Section: Introductionmentioning

confidence: 99%

Cardiorespiratory parameters during submaximal exercise under acute exposure to normobaric and hypobaric hypoxia

Basualto-Alarcón

Rodas

Galilea

et al. 2012

Apunts. Medicina de l'Esport

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Seven healthy young men were submitted twice to a hypoxia tolerance test at a simulated altitude (3000 m). Their first acute exposure was in a hypobaric chamber; and the second, in a hypoxic tent. Cardiorespiratory parameters and heart rate variability measurements were obtained under each hypoxic condition. A significant decrease of 6% to 8% compared to normal oxygen conditions was observed in arterial oxygen saturation (SpO 2 ) in both hypoxic conditions at rest; whereas exercise led to decreases of 10% in SpO 2 despite an increase of 27% in respiratory minute volume. The low frequency (LF) and high frequency (HF) components of heart rate variability significantly changed from normoxia (LF: 37.1, HF: 62.9, LF/HF: 1.27) to hypobaric hypoxia (HH) (LF: 49.1, HF: 50.6, LF/HF: 1.96). However, these changes were not observed under normobaric hypoxia. Thus, heart rate variability behaved differently in the two hypoxic conditions, supporting the hypothesis that normobaric hypoxia and hypobaric hypoxia are not equal stimuli to the cardiovascular and respiratory systems. A correlation was found between sympathetic and vagal modulations in normoxia and SpO 2 at exercise under hypobaric hypoxia (HH). Individuals with higher sympathetic modulation (LF%) in normoxia had higher SpO 2 at exercise under HH (r = 0.808, P < 0.05) and individuals with higher vagal modulation (HF%) in normoxia showed a trend to lower SpO 2 in exercise under HH (r = −0.636, P = 0.125). This opens up the possibility of using this correlation as a tool for predicting the individual capacity to altitude acclimatization. © 2011 Consell Català de l'Esport. Generalitat de Catalunya. Published by Elsevier España, S.L. All rights reserved. * Corresponding author. E-mail address: gviscor@ub.edu (G. Viscor). PALABRAS CLAVEVariabilidad de la frecuencia cardiaca; Prueba de tolerancia a hipoxia; Tienda hipóxica; Cámara hipobárica; Saturación arterial de oxígeno Parámetros cardiorrespiratorios durante ejercicio submáximo en hipoxia aguda hipobárica y normobáricaResumen Siete jóvenes sanos y en buena condición física realizaron dos pruebas de tolerancia a hipoxia a una altitud simulada de 3.000 m. La primera fue en cámara hipobárica, mientras que la segunda se efectuó en una tienda hipóxica. Se registraron varios parámetros cardiorrespiratorios y la variabilidad de la frecuencia cardiaca. En comparación con las condiciones de normoxia, se observó un decremento significativo del 6% al 8% en la saturación de oxígeno arterial (SpO 2 ) en reposo en ambas condiciones de hipoxia. El ejercicio desencadenó descensos de un 10% en SpO 2 pese a un incremento del 27% del volumen minuto ventilatorio. Tanto los componentes de baja (LF) como alta frecuencia (HF) de la variabilidad del ritmo cardiaco cambiaron significativamente en hipoxia hipobárica (LF: 49,1, HF: 50,6, LF/HF: 1,96) respecto a normoxia (LF: 37,1, HF: 62,9, LF/HF: 1,27). Estos cambios no se apreciaron en condiciones de hipoxia normobárica, lo cual apoya la hipótesis de que la hipoxia hipobárica y norm...

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Autonomic control of the cardiovascular system during acclimatization to high altitude: effects of sildenafil

Cited by 66 publications

References 32 publications

Autonomic Nervous System

Autonomic Nervous System

Acclimatization to chronic intermittent hypoxia in mine workers: a challenge to mountain medicine in Chile

Cardiorespiratory parameters during submaximal exercise under acute exposure to normobaric and hypobaric hypoxia

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