title: Effects of extreme endurance running on cardiac autonomic nervous modulation in healthy trained subjects.
abstract: This study examined spectral components of heart rate variability (HRV) during endurance mountain running in 8 healthy trained subjects. The data showed that during this type of mountain running, all spectral components of HRV may severely decrease, particularly very-low-frequency and low-frequency (LF) power, suggesting extreme activation of the sympathetic nervous system. The physiologic response of the heart in this situation was the downregulation of the beta-adrenergic receptors to protect myocardial function, with a subsequent increase in parasympathetic tone, reflected by an increase in high-frequency (HF) power and a decrease in the LF/HF ratio.
authors.affiliation: Cardiology Center, Department of Internal Medicine, University Hospital, Geneva, Switzerland. juan.sztajzel@hcuge.ch
authors.forename: Juan
authors.initials: J
authors.lastname: Sztajzel
authors.forename: Guillaume
authors.initials: G
authors.lastname: Atchou
authors.forename: Richard
authors.initials: R
authors.lastname: Adamec
authors.forename: Antonio
authors.initials: A
authors.lastname: Bayes de Luna
mesh_terms: D000328:Adult; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D012420:Running / Q000502:physiology*
chemical_list: D011943:Receptors, Adrenergic, beta