Abstract
BackgroundRhodiola crenulata (R. crenulata) is widely used to prevent acute mountain sickness in the Himalayan areas and in Tibet, but no scientific studies have previously examined its effectiveness. We conducted a randomized, double-blind, placebo-controlled crossover study to investigate its efficacy in acute mountain sickness prevention.MethodsHealthy adult volunteers were randomized to 2 treatment sequences, receiving either 800 mg R. crenulata extract or placebo daily for 7 days before ascent and 2 days during mountaineering, before crossing over to the alternate treatment after a 3-month wash-out period. Participants ascended rapidly from 250 m to 3421 m on two separate occasions: December 2010 and April 2011. The primary outcome measure was the incidence of acute mountain sickness, as defined by a Lake Louise score ≥ 3, with headache and at least one of the symptoms of nausea or vomiting, fatigue, dizziness, or difficulty sleeping.ResultsOne hundred and two participants completed the trial. There were no demographic differences between individuals taking Rhodiola-placebo and those taking placebo-Rhodiola. No significant differences in the incidence of acute mountain sickness were found between R. crenulata extract and placebo groups (all 60.8%; adjusted odds ratio (AOR) = 1.02, 95% confidence interval (CI) = 0.69–1.52). The incidence of severe acute mountain sickness in Rhodiola extract vs. placebo groups was 35.3% vs. 29.4% (AOR = 1.42, 95% CI = 0.90–2.25).ConclusionsR. crenulata extract was not effective in reducing the incidence or severity of acute mountain sickness as compared to placebo.Trial registrationClinicalTrials.gov NCT01536288.
Highlights
Rhodiola crenulata (R. crenulata) is widely used to prevent acute mountain sickness in the Himalayan areas and in Tibet, but no scientific studies have previously examined its effectiveness
Acute mountain sickness (AMS) occurs in individuals rapidly ascending to high altitude and it usually results in headache, along with anorexia or nausea, fatigue, dizziness, and insomnia [1]
All participants were exposed to the same temperatures, as no statistically significant differences were found between the four ascents (Table 1)
Summary
Ethics statement This study has been approved by the Institutional Review Board (IRB) of Chang Gung Medical Foundation, Linkou Medical Center, Taoyuan, Taiwan. The number inside the envelope determined the treatment sequence that each participant was allocated to (Rhodiolaplacebo or placebo-Rhodiola). Participants were not permitted to self-treat their AMS symptoms Instead, they were told in advance that investigators would provide oral acetaminophen (500 mg) or ibuprofen (400 mg) for headache, meclizine (25 mg) for dizziness or intramuscular prochlorperazine (5 mg) for nausea and/or vomiting. According to the study design, assuming the absence of carry-over or period effects, a sample size of 133 participants was deemed sufficient to provide a power of 80% with a two-sided alpha level of 0.1 and a probability of discordant pairs of 0.7 to detect an odds ratio for the incidence of AMS of 0.59 between the Rhodiola group and the placebo group.
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