When the Air Gets Thin: Understanding Altitude Sickness

When the Air Gets Thin: Understanding Altitude Sickness

Altitude sickness, also known as acute mountain sickness (AMS), occurs when the body struggles to adjust to lower oxygen levels at high elevations. It typically develops at altitudes above 8,000 feet and can affect hikers, skiers, and travelers visiting mountainous regions. As elevation increases, air pressure decreases, making it harder for the body to obtain adequate oxygen. Symptoms can range from mild discomfort to serious, life-threatening complications. Recognizing symptoms early and responding appropriately is essential for safety at high altitudes. Read the following blog to learn more about altitude sickness!

Causes of Altitude Sickness

Altitude sickness is caused by reduced oxygen availability at high elevations. When the body ascends too quickly, it does not have enough time to adjust to lower oxygen levels. Some of the most common causes of altitude sickness are:

• Rapid ascent to high altitude: Climbing or traveling to high elevations too quickly prevents proper acclimatization.

• Low oxygen levels in the air: Higher altitudes contain less available oxygen, stressing the respiratory system.

• Inadequate acclimatization time: Skipping gradual elevation increases the risk of symptoms.

• Physical exertion at high elevation: Intense activity raises the amount of oxygen needed, worsening symptoms.

Risk Factors for Altitude Sickness

Certain factors increase the likelihood of developing altitude sickness. These risk factors affect how well the body adapts to high elevations. Some of the most common risk factors for altitude sickness include of:

• Ascending above 8,000 feet: The risk increases significantly at higher elevations where less oxygen is available.

• Previous history of altitude sickness: Individuals who have experienced it before are more likely to develop it again.

• Rapid travel by plane or vehicle to high altitude: Quick elevation gain limits the body’s ability to adjust.

• Dehydration: Fluid loss can worsen symptoms and impair oxygen circulation.

• High physical activity immediately upon arrival: Overexertion increases oxygen demand before acclimatization occurs.

Symptoms of Altitude Sickness

Symptoms often appear within hours of reaching high altitude. They may resemble flu-like symptoms but are directly related to oxygen deprivation. Some of the most common symptoms of altitude sickness are:

• Headache: A persistent headache is one of the earliest and most common symptoms. They can be very intense and uncomfortable.

• Nausea and vomiting: Digestive discomfort can occur as the body reacts to the low oxygen levels.

• Dizziness or lightheadedness: Reduced oxygen supply affects balance and coordination.

• Fatigue and weakness: Low oxygen levels decrease energy production in the body.

• Shortness of breath: Breathing may feel more difficult from the decreased oxygen, especially during exertion.

Effects of Altitude Sickness

If not addressed, altitude sickness can progress into more serious conditions. Severe cases require immediate medical attention. Some of the most common effects of altitude sickness include of:

• Reduced physical performance: Activities such as walking, running, or hiking become more difficult.

• Confusion or poor coordination: Brain function may be affected in severe cases.

• Fluid buildup in lungs (HAPE): High-altitude pulmonary edema causes breathing difficulty and chest tightness.

• Fluid buildup in the brain (HACE): High-altitude cerebral edema leads to severe neurological symptoms.

Types of Altitude Sickness

Altitude sickness is commonly categorized based on the severity and the body system affected. Identifying the type of altitude sickness can help determine treatment type and urgency. Some of the most common types of altitude sickness are:

• Acute Mountain Sickness (AMS): The mildest and most common form, causing headache and nausea.

• High-Altitude Pulmonary Edema (HAPE): A serious condition involving fluid accumulation in the lungs.

• High-Altitude Cerebral Edema (HACE): A life-threatening condition involving swelling of the brain.

Treatments for Altitude Sickness

Treatments depend on symptom severity. The primary goal is restoring oxygen levels and preventing progression. These treatments will help with comfort. Some of the most useful treatment for altitude sickness are:

• Descending to a lower altitude: Moving to a lower elevation is the most effective treatment.

• Rest and limiting physical activity: Reducing exertion allows the body to adjust.

• Hydration: Adequate fluids support circulation and oxygen delivery.

• Supplemental oxygen: The use of oxygen therapy helps relieve symptoms in moderate to severe cases.

• Medications such as acetazolamide: Certain medications can assist acclimatization and symptom relief.

A Day in the Life with Altitude Sickness

Living with altitude sickness can quickly turn an exciting trip into a physically challenging experience. A person may wake up with a throbbing headache and feel unusually tired or nauseated. Simple tasks like walking uphill or carrying gear may cause shortness of breath. Rest becomes necessary, and activities are often postponed or canceled. In more severe cases, descending to a lower altitude becomes the priority for safety.

• Morning headaches and fatigue: Symptoms are often worse after the first night at high elevation. This can make fun events not enjoyable due to high levels of discomfort.

• Limited physical activity: Even light exertion may cause dizziness or breathlessness.

• Frequent rest breaks: Recovery requires slowing down and conserving energy. The body needs extra time to recover from working.

• Careful symptom monitoring: Watching for worsening signs is essential to prevent complications.

• Possible early descent: Safety may require cutting a trip short to lower altitude.

Citations

Clinic, Cleveland. “Altitude Sickness: Not Always an Uphill Battle.” Cleveland Clinic, 17 Dec. 2025, https://my.clevelandclinic.org/health/diseases/15111-altitude-sickness

CDC. “High-Altitude Travel and Altitude Illness.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 2025, https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html

UK, NHS. “Altitude Sickness.” NHS Choices, NHS, 2024 https://www.nhs.uk/conditions/altitude-sickness/