Overview
Altitude sickness happens when the body does not adjust well to lower oxygen levels at higher elevations. It includes acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE). AMS is the mildest form, while HACE and HAPE are medical emergencies.
Key Symptoms
Mild altitude sickness often causes headache, loss of appetite, nausea, dizziness, unusual tiredness, and poor sleep. More serious warning signs include severe shortness of breath, cough, chest tightness, confusion, trouble walking straight, extreme weakness, or blue lips or fingernails. Symptoms may begin within hours after arrival at altitude and can worsen if the person keeps climbing.
Causes and Risk Factors
The main cause is going to high altitude faster than the body can adapt to lower oxygen levels. Sleeping at a higher elevation each night, strenuous activity soon after arrival, and a past history of altitude illness can raise risk. Anyone can be affected, including healthy and physically fit people.
Who Is Affected
Travelers, hikers, trekkers, climbers, skiers, and people flying or driving quickly to mountain areas can develop altitude sickness. People visiting high places for work, tourism, or religious travel may also be affected. Children and adults can both get it.
Prevention
The main way to lower risk is to ascend gradually and give the body time to acclimatize. Avoid going higher to sleep too quickly, and take it easy for the first day or two at altitude. If you have had altitude sickness before or are planning rapid ascent, ask a healthcare professional before travel about prevention options and your personal risk.
Diagnosis and Tests
Diagnosis is usually based on recent altitude exposure and the pattern of symptoms. A healthcare professional may check breathing, oxygen level, heart rate, and mental status, and look for signs of serious illness. Tests may be used to rule out other problems or assess complications, especially if severe symptoms are present.
Treatment Categories
For mild symptoms, the usual approach is to stop ascending, rest, and monitor closely. If symptoms do not improve or if they worsen, the person should go to a lower altitude and get medical help. Severe forms such as HACE or HAPE need urgent treatment, which may include oxygen and emergency evacuation to lower altitude.
When to Seek Medical Care
Seek medical care if symptoms of altitude sickness are moderate, are not improving with rest, or are making it hard to eat, drink, walk, or sleep. Medical advice is also important for anyone with heart or lung disease who plans travel to high altitude. Do not continue ascending while symptoms are present.
When It May Be an Emergency
Get emergency help right away for confusion, unusual behavior, fainting, inability to walk normally, severe shortness of breath at rest, coughing up frothy sputum, chest pain, or blue lips. These can be signs of dangerous swelling in the brain or fluid in the lungs at high altitude. Immediate descent and urgent medical care are critical.