What is a critical step in providing care for someone who has acute mountain sickness?

Descending to a lower altitude is the most critical step in providing care for someone experiencing acute mountain sickness (AMS). When an individual suffers from AMS, the symptoms typically result from the body's inability to acclimatize to high altitudes due to lower oxygen levels. Descending helps alleviate symptoms by increasing the availability of oxygen as the pressure improves at lower elevations, allowing the body to recover more effectively from the effects of altitude.

While staying hydrated is important and pain medications can offer temporary relief for headaches or discomfort, these measures do not address the underlying issue of insufficient acclimatization. Ascending further only exacerbates the condition by increasing altitude exposure, which can lead to more severe symptoms. Therefore, the most effective and immediate response to AMS is to descend to a lower altitude where oxygen levels are higher and the risk of complications decreases.