| Title | Effects of extreme endurance running on cardiac autonomic nervous modulation in healthy trained subjects. | ||
| Author | Sztajzel, Juan; Atchou, Guillaume; Adamec, Richard; Bayes de Luna, Antonio | ||
| Journal | Am J Cardiol | Publication Year/Month | 2006-Jan |
| PMID | 16442378 | PMCID | -N/A- |
| Affiliation | 1.Cardiology Center, Department of Internal Medicine, University Hospital, Geneva, Switzerland. juan.sztajzel@hcuge.ch. | ||
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.