Autonomic nervous control of heart rate at altitude (5050 m).

Détails

ID Serval
serval:BIB_BFC3CD4F121D
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Autonomic nervous control of heart rate at altitude (5050 m).
Périodique
European Journal of Applied Physiology and Occupational Physiology
Auteur⸱e⸱s
Farinelli C.C., Kayser B., Binzoni T., Cerretelli P., Girardier L.
ISSN
1439-6319
ISSN-L
0301-5548
Statut éditorial
Publié
Date de publication
1994
Volume
69
Numéro
6
Pages
502-507
Langue
anglais
Résumé
To investigate possible changes in autonomic regulation of heart rate as a result of acclimatization to high altitude, indexes of autonomic nervous activity were obtained non invasively by spectrum analysis of heart rate variability on five healthy male subjects [age, 31 (SEM 2) years] during a postural change from supine to seated, both at sea level and after 1 month of exposure to an altitude of 5050 m. Heart rate fluctuations at the respiratory frequency (high frequency, HF) are mediated by the parasympathetic system whereas fluctuations at about 0.1 Hz (low frequency, LF) are due to both sympathetic and parasympathetic nervous systems. Maximal heart rate, as measured during an incremental exercise test, decreased from 184 (SEM 5) beats.min-1 at sea level to 152 (SEM 2) beats.min-1 at 5050 m. At sea level, the change in posture from supine to seated induced an increase in LF amplitude accompanied by an increase or a decrease in HF amplitude, whereas after 1 month at altitude the HF amplitude decreased in all subjects, with little or no change in LF amplitude. These results indicate a changed strategy of heart rate regulation after acclimatization to high altitude. At sea level, the postural change induced an increase in sympathetic activity in all subjects with different individual vagal responses, whereas at altitude the postural change induced a net decrease in vagal tone in all subjects, with little or no change in sympathetic activity. These results corroborate the reported reduced sensitivity of the heart to adrenergic drive in chronic hypoxia, which may, at least in part, explain the decreased maximal heart rate in altitude-acclimatized human subjects.
Mots-clé
Acclimatization/physiology, Adult, Altitude, Autonomic Nervous System/physiology, Electrocardiography, Heart Rate/physiology, Humans, Male, Signal Processing, Computer-Assisted
Pubmed
Web of science
Création de la notice
19/09/2013 10:17
Dernière modification de la notice
20/08/2019 15:34
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