acute mountain sickness

noun

: altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting, insomnia, dizziness, and fatigue, and may lead to serious complications including severe edema of the brain or lungs

—abbreviation AMS

Examples of acute mountain sickness in a Sentence

Recent Examples on the Web

There are three main types: acute mountain sickness, which is the mildest and most common form and whose defining feature is headaches; high-altitude cerebral edema, which involves swelling in the brain; and high-altitude pulmonary edema, which involves swelling in the lungs. —Alex Hutchinson, Outside, 15 Sep. 2025

Altitude sickness, which most commonly refers to acute mountain sickness, presents a significant challenge to those traveling to and adventuring in high-altitude destinations. —Brian Strickland, Discover Magazine, 9 Mar. 2024

To begin with, there are three kinds of altitude sickness: acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema. —Allie Conti, Field & Stream, 27 Sep. 2023

The acute mountain sickness diagnosis came later, when Lt. Alkonis was evaluated by a U.S. Navy neurologist after his release from jail. —The Editorial Board, WSJ, 1 Mar. 2023

And in 2015, a 14-year-old called Warren Asiyo died from acute mountain sickness while on a church trip. —Kang-Chun Cheng, The Christian Science Monitor, 20 Oct. 2022

Word History

First Known Use

1903, in the meaning defined above

Rhymes for acute mountain sickness

• homesickness
• seasickness
• quickness
• thickness

Medical Definition

acute mountain sickness

noun

: altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting, insomnia, dizziness, and fatigue

Note: Acute mountain sickness can lead to serious complications including severe edema of the brain or lungs.

… acute mountain sickness … is common in travelers who ascend rapidly to altitudes above 8,000 feet.

—Erick A. Weiss, Rock & Ice Magazine

—abbreviation AMS