Altitude Sickness: What It Is, Why It Happens, and How to Stay Safe

When dealing with altitude sickness, the collection of symptoms that appear when you ascend too quickly to high elevations where oxygen is thin. Also known as acute mountain illness, it can range from a mild headache to life‑threatening brain swelling.

In practice, hypoxia, the reduced oxygen pressure at high altitude is the core trigger, so altitude sickness essentially encompasses hypoxia. The body’s response hinges on acclimatization, a gradual exposure process that lets breathing, blood count, and circulation adjust. When you give your body time to adapt, the risk drops dramatically. If the climb is too fast, many travelers turn to acetazolamide, a carbonic anhydrase inhibitor that forces faster breathing and improves oxygen delivery as a preventive step. Studies show that the drug can cut the incidence of moderate symptoms by up to 50 % when started a day before ascent. Together, these three elements—hypoxia, acclimatization, and acetazolamide—form a logical chain: altitude sickness requires proper acclimatization, and preventive medication influences outcomes.

Practical Tips to Manage the Risk

First, know the common warning signs: headache, nausea, dizziness, and trouble sleeping. If you notice these within the first 24 hours, pause the climb and hydrate. Second, follow the “300‑meter rule”: limit daily gains to about 1,000 feet above 2,500 meters, and add a rest day for every additional 600 meters. Third, keep moving slowly once you’re above 3,000 meters; a steady pace lets the body fine‑tune its oxygen uptake. Fourth, consider a low‑dose acetazolamide regimen (125 mg twice daily) if you have a history of symptoms or plan rapid ascents. Finally, be aware of severe forms like high‑altitude pulmonary edema (HAPE) and high‑altitude cerebral edema (HACE); these require immediate descent and medical care. Carry a pulse‑oximeter to monitor oxygen saturation—values below 85 % signal a red flag.

Armed with these basics, you’ll be able to read the signs, pace your ascent, and decide when medication makes sense. Below you’ll find a curated set of articles that dive deeper into specific drugs, compare treatment options, and explain the science behind the body’s adaptation. Use them to fine‑tune your plan and stay healthy while you chase the summit.