Sleeping with Elevated Upper Body Does Not Attenuate Acute Mountain Sickness: Pragmatic Randomized Clinical Trial

Area of Science:

• Altitude Medicine
• Sleep Physiology
• High-Altitude Physiology

Background:

• Acute mountain sickness (AMS) is a common condition affecting individuals ascending to high altitudes.
• Sleep can exacerbate AMS symptoms, with cephalad fluid shifts implicated in its pathophysiology.

Purpose of the Study:

• To investigate whether sleeping with the upper body elevated by 30 degrees reduces the risk and severity of acute mountain sickness.
• To assess the impact of upper body elevation on AMS symptoms and sleep efficiency at high altitude.

Main Methods:

• A pragmatic, randomized, observer-blinded field study was conducted at 4554 meters altitude.
• 134 adults with existing AMS symptoms were randomized to sleep with upper body elevation (30 degrees) or in a horizontal position.
• The primary endpoint was the change in the Acute Mountain Sickness-Cerebral (AMS-C) score; sleep efficiency was a secondary endpoint.

Main Results:

• The AMS-C score increased slightly in both groups, with no statistically significant difference between the elevated and horizontal sleeping positions (P = .308).
• Oxygen saturation levels were similar between the intervention and control groups (P = .863).
• No significant difference in sleep efficiency was observed between the two sleeping conditions (P = .115).

Conclusions:

• Elevating the upper body by 30 degrees while sleeping at high altitude does not significantly reduce acute mountain sickness symptoms.
• This sleeping position did not lead to relevant improvements in hypoxemia or sleep efficiency in the study population.