| Title | Acute effects of ephedra on autonomic nervous modulation in healthy young adults. | ||
| Author | Chen, W-L; Tsai, T-H; Yang, C C H; Kuo, T B J | ||
| Journal | Clin Pharmacol Ther | Publication Year/Month | 2010-Jul |
| PMID | 20520603 | PMCID | -N/A- |
| Affiliation | 1.Institute of Traditional Medicine, National Yang-Ming University, Taipei, Taiwan. | ||
The aim of this study was to assess the acute effects of ephedra on autonomic nervous modulation by means of heart rate variability (HRV) analysis, using a randomized, double-blind, placebo-controlled, crossover design. On three separate days, 20 healthy subjects took capsules containing either 1 or 2 g of ephedra dry extract or a placebo, and the sequential percentage changes in HRV measures were compared. After the subjects took ephedra, the normalized low-frequency component (LF) and the ratio of LF to high-frequency component (HF) increased significantly in a dose-dependent manner, whereas the normalized HF (HF%) decreased significantly. We conclude that ingestion of ephedra tilts the sympathovagal balance dose-dependently toward increased sympathetic activity and impairs parasympathetic activity.