A 25-year-old man is climbing from an altitude of 6,500 feet to 8,200 feet and complains of weakness and nausea. What is he most likely experiencing?

The symptoms presented by the 25-year-old man, specifically weakness and nausea during ascent from 6,500 feet to 8,200 feet, are indicative of Acute Mountain Sickness (AMS). AMS typically occurs when individuals ascend to higher altitudes too quickly without allowing their bodies sufficient time to acclimate to the decreases in oxygen levels found at these elevations.

Common symptoms of AMS include headache, nausea, dizziness, fatigue, and sometimes difficulty sleeping. The key factor here is the recent increase in altitude, which puts the individual at risk for AMS, especially given the short time frame during which they are experiencing these symptoms. The elevation gain, combined with the symptoms, aligns well with the typical presentation of AMS.

Other conditions like High-altitude pulmonary edema (HAPE), High-altitude cerebral edema (HACE), and Decompression sickness involve more severe symptoms and generally occur under different circumstances. HAPE typically includes symptoms such as cough and difficulty breathing due to fluid in the lungs, which the person does not exhibit. HACE involves serious neurological symptoms such as confusion or loss of coordination, which are also not evident here. Decompression sickness occurs when a diver ascends too quickly from deep water and is unrelated to high altitude changes. Thus, the