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Don't Let Altitude Sickness Get You Down: Learn to Prevent, Recognize, & Treat It

Altitude sickness affects 1 out of 2 people who climb a 14er, and 1 in 3 people who visit Rocky Mountain National Park. Learn how to prevent altitude sickness, recognize its symptoms in the field, and treat them effectively with our science-backed free guide.

Table of Contents

What is Altitude Sickness?

Altitude sickness, often referred to as Acute Mountain Sickness (AMS), is a medical condition that can affect individuals who ascend to high elevations too quickly. AMS and altitude sickness are related terms, with AMS being a subtype that specifically deals with neurological symptoms. They occur when your body doesn’t have enough time to adapt to the lower levels of oxygen and reduced air pressure at higher elevations. Altitude sickness can be encountered in various mountainous regions around the world, including the Rocky Mountains of Colorado.

This condition is not just an inconvenience but a risk multiplier. The symptoms of altitude sickness can impede decision-making, affect balance, and lead to dehydration. This makes activities like hiking, camping, and skiing more hazardous.


Q: What happens during altitude sickness?

A: Altitude sickness occurs when you cannot get enough oxygen from the air at high altitudes. This leads to symptoms such as headaches, dizziness, and shortness of breath. At higher altitudes, the pressure of the air decreases, and thus, the amount of oxygen available decreases. This can result in hypoxia, a condition where there’s not enough oxygen in the body to sustain bodily functions.

A: Risk factors include rapid ascent to high altitudes, a lack of acclimatization, previous history of altitude sickness, and individual susceptibility. Physical fitness does not necessarily provide immunity against AMS. Certain pre-existing health conditions like heart or lung diseases can also increase susceptibility.

A: The three main types are Acute Mountain Sickness (AMS), High-Altitude Cerebral Edema (HACE), and High-Altitude Pulmonary Edema (HAPE). AMS is the mildest and most common, HACE is a severe form affecting the brain, and HAPE affects the lungs.

A: Altitude sickness typically starts at elevations as low as 2,500 meters (8,200 feet) above sea level and becomes more common and severe at altitudes above 3,500 meters (11,500 feet).

Altitude Sickness Prevention

Dispersed camping in Colorado

Acclimatizing to the high elevations found in the Colorado Rocky Mountains is crucial for both residents and visitors who want to enjoy outdoor activities safely. Failure to properly acclimatize can result in altitude sickness, which can range from mild symptoms to life-threatening conditions like HAPE (High-Altitude Pulmonary Edema) or HACE (High-Altitude Cerebral Edema). 

Here are some of the best standard practices for acclimatization:

Acclimatization with a Gradual Ascent

Initial Stage: Spend 1-2 nights at a moderate elevation (around 5,000 to 7,000 feet) to give your body a chance to adapt to increased altitude.

Further Ascent: Avoid increasing your sleeping elevation by more than 1,500-2,000 feet per day after that.

Climb High, Sleep Low

Day hikes to higher elevations, followed by returning to a lower elevation for sleep, can help your body adjust gradually. For example, before climbing a 14er, setup camp or stay at a motel at 9,000 feet elevation. Take a day hike up to 10,500-11,000 feet, before returning to your accomidation for the night. 

Medication Options

While most people don’t need medication to prevent AMS, it might be a good idea if you have a history of developing altitude sickness symptoms. Consult your doctor about medications like Diamox that can help in AMS prevention. 


Q: How can I prevent altitude sickness in Colorado?

A: In Colorado, gradual acclimatization is key. Spending a couple of nights at a moderate elevation can be beneficial before ascending higher. Also, adhering to the principle of “climb high, sleep low,” proper hydration, and consultation with a healthcare provider for preventive medication can aid in prevention.

A: Acetazolamide (Diamox) is commonly prescribed for preventing altitude sickness. It helps to speed up acclimatization. Always consult a healthcare provider for proper diagnosis and prescription.

A: Acetazolamide (Diamox) is the most commonly used medication, but others like Dexamethasone and Nifedipine are used for more severe types of altitude sickness like HACE and HAPE.

A: Hydration is crucial but overhydration can lead to dilution of electrolytes in the body. Generally, 3-4 liters of water per day is advised. Avoid alcohol and caffeine, as they can lead to dehydration.

The Symptoms of Altitude Sickness

Recognizing the symptoms of Acute Mountain Sickness (AMS) is crucial for anyone venturing into high-altitude areas. Understanding the severity of these symptoms can help determine the appropriate course of action, which can sometimes be life-saving. Here’s a more comprehensive look at the symptoms and how to recognize them:

Mild Symptoms

  • Headache: Usually starts as a dull ache and can intensify. It’s often the first sign of AMS.
  • Dizziness: Feelings of light-headedness or unsteadiness.
  • Nausea: General stomach upset or discomfort, sometimes accompanied by loss of appetite.
  • Fatigue: Unusual tiredness or weakness, often out of proportion to the physical effort exerted.

Moderate Symptoms

  • Severe Headache: Unrelieved by over-the-counter medications or lying down.
  • Vomiting: Persistent or severe nausea that leads to vomiting.
  • Difficulty Walking: Trouble with balance, coordination, and may also exhibit poor judgment.
  • Breathlessness: Shortness of breath even when resting.

Severe Symptoms

  • Confusion: Altered mental state, including difficulty thinking clearly or making decisions.
  • Shortness of Breath: Severe breathing difficulties, possibly with a blue tinge to the skin (cyanosis).
  • Loss of Consciousness: This is an extremely dangerous symptom and requires immediate descent and medical attention.


Q: How do you know if you have altitude sickness?

A: Symptoms like headaches, dizziness, fatigue, and nausea are common indicators. In more severe cases, difficulty in walking, breathlessness, and confusion can occur. These symptoms are usually worse at night.

A: Four key symptoms are headache, nausea, fatigue, and dizziness. These can vary in intensity and may be accompanied by other symptoms like shortness of breath and poor coordination.

A: Early warning signs include a mild headache, dizziness, and fatigue. These symptoms often manifest within a few hours of ascent and can be worse during the night.

A: Severe headaches, vomiting, and breathlessness at rest are extremely concerning symptoms. Cognitive symptoms like confusion or loss of coordination are also very serious and indicate the potential onset of HACE.

Treating Altitude Sickness

injured hunter rescued custer SAR

The symptoms of mild AMS, like nausea and headache, can often be addressed with OTC medication, hydration, and a slower pace and effort. However, if symptoms do not resolve they will eventually progress and threaten causing an emergency.

If you suspect you’re experiencing moderate or severe AMS, descend immediately and rest.

For moderate to severe symptoms, immediate medical attention is crucial. If you fall unconscious or become incapacitated if may be impossible to move you to a lower elevation to address your symptoms.


Q: What is the best remedy for altitude sickness?

A: The most effective treatment for altitude sickness is to descend to a lower elevation as quickly and safely as possible. Oxygen therapy and medications like Diamox may also be used to treat symptoms.

A: Yes, descent is the most effective treatment. Medications can help alleviate symptoms but are not a substitute for descent or medical evaluation. Oxygen therapy can also be effective.

A: There’s no quick fix for acclimatization. The body generally takes several days to acclimatize to high altitudes. Prophylactic medications can aid but are not a replacement for gradual acclimatization.

A: Immediate descent is crucial. Oxygen therapy is typically administered, and medications like Dexamethasone for HACE and Nifedipine for HAPE may be used. These are extremely serious conditions that require urgent medical attention.

Additional Resources:

Watch our Webinar: Altitude Sickness 101

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