Pressurization and acute mountain sickness

Area of Science:

• Altitude Medicine
• Physiology
• Environmental Health

Background:

• Acute mountain sickness (AMS) is a common concern for trekkers at high altitudes.
• Portable pressure chambers have been anecdotally reported as effective AMS treatments.
• The efficacy of early pressurization for preventing AMS during rapid ascent has not been well-studied.

Purpose of the Study:

• To investigate if early, short-term pressurization can prevent or delay AMS symptoms in unacclimatized individuals during rapid high-altitude ascent.
• To test the hypothesis that a 3-hour exposure in a portable pressure chamber upon arrival at high altitude mitigates AMS.

Main Methods:

• 51 healthy subjects rapidly ascended from 1,030m to 4,360m in the Alps within 12 hours.
• Upon arrival, subjects' AMS scores, oxygen saturation (SaO2), and heart rate (HR) were measured.
• Subjects were randomly assigned to a 3-hour pressurization group or a control group.

Main Results:

• Immediately after treatment, the pressurization group showed a significant decrease in AMS scores and an increase in SaO2 compared to the control group.
• However, by the following morning, AMS scores, SaO2, and HR were similar between the pressurized and control groups.
• The intervention demonstrated a slight delay in AMS onset but did not prevent its occurrence or reduce its severity.

Conclusions:

• Early 3-hour pressurization offers a temporary improvement in AMS symptoms and oxygenation following acute altitude exposure.
• This intervention does not provide a long-term preventative effect against AMS development or severity.
• Further research may explore different pressurization protocols or combinations with other acclimatization strategies.