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

Article Article scientifique Article Autonomic nervous control of heart rate at altitude (5050 m) eng 1994 author Farinelli Cédric 24221 author Kayser Bengt E. 0000-0002-9776-7501 24108 author Binzoni Tiziano 0009-0004-2592-7926 23000 author Cerretelli Paolo 25401 author Girardier Lucien 24900 502-507 10.1007/BF00239867 7713070 0301-5548 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. Acclimatization/physiology Adult Altitude Autonomic Nervous System/physiology Electrocardiography Heart Rate/physiology Humans Male Signal Processing, Computer-Assisted Dewey 616.0757 Dewey 616.8 53 Département de neurosciences fondamentales 21A 62 Département de radiologie et informatique médicale 227 false 184 Groupe Binzoni Tiziano (radiologie) 234 European journal of applied physiology and occupational physiology 69 6 b398ade5-b069-4b7c-9faf-77aabd2a25d6 Article (Published version) Restricted art%3A10.1007%2FBF00239867.pdf 684934 application/pdf restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de neurosciences fondamentales Faculté de médecine / Section de médecine clinique / Département de radiologie et informatique médicale

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Autonomic nervous control of heart rate at altitude (5050 m)	European journal of applied physiology and occupational physiology			1994	461	0

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Girardier, Lucien