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Acute Effects of Ephedra on Autonomic Nervous Modulation in Healthy Young Adults
Author(s) -
Chen WL,
Tsai TH,
Yang C C H,
Kuo T B J
Publication year - 2010
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.2010.66
Subject(s) - heart rate variability , placebo , crossover study , autonomic nervous system , medicine , clinical pharmacology , balance (ability) , heart rate , ingestion , pharmacology , cardiology , anesthesia , physical therapy , blood pressure , pathology , alternative medicine
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. Clinical Pharmacology & Therapeutics (2010) 88 1, 39–44. doi: 10.1038/clpt.2010.66