Which symptom indicates Acute Mountain Sickness might be developing?

The development of Acute Mountain Sickness (AMS) is characterized by a collection of symptoms that often emerge when individuals ascend to high altitudes too quickly. A headache accompanied by dizziness is a key indicator of AMS. This combination suggests that the body is struggling to acclimatize to decreased oxygen levels typical of elevated heights.

A severe headache alone can occur for a variety of reasons and does not specifically indicate AMS without accompanying symptoms. Increased appetite is not a symptom of AMS; in fact, many individuals may experience a decrease in appetite due to the discomfort associated with altitude. Lastly, decreased fatigue is contrary to what individuals often experience with AMS, as fatigue often increases as the body grapples with the effects of altitude sickness. Thus, the presence of a headache along with dizziness is a strong signal that AMS may be taking hold, making it critically important for individuals to recognize and respond to these symptoms promptly.