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Effects of extreme endurance running on cardiac autonomic nervous modulation in healthy trained subjects
Juan Sztajzel1, Guillaume Atchou, Richard Adamec
1Cardiology Center, Department of Internal Medicine, University Hospital, Geneva, Switzerland. juan.sztajzel@hcuge.ch
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.
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