Colorado is a fantastic place to live, work, and explore—especially for those who love hiking, skiing, cycling, or simply taking in the spectacular mountain views. If you’re visiting Boulder County or heading up to higher elevations like Rocky Mountain National Park, Nederland, or points beyond, it’s essential to know how to prevent altitude sickness and recognize the warning signs.
Even healthy, active people can develop severe symptoms if they ascend too quickly or overexert themselves. If you feel unwell, don’t try to push through it. Rest, hydrate, and get medical help if your symptoms are severe. The mountains will still be here when you feel better.
What Is Altitude Sickness?
Even healthy, active people can develop severe symptoms if they ascend too quickly or overexert themselves. If you feel unwell, don’t try to push through it. Rest, hydrate, and get medical help if your symptoms are severe. The mountains will still be here when you feel better.[/ts_blockquote]Altitude sickness happens when your body doesn’t have time to adjust to thinner air and lower oxygen levels at elevation. Even elevations as low as 5,000–8,000 feet—standard throughout Boulder County—can trigger symptoms in some people. Three types of altitude sickness can occur, sometimes overlapping.
Acute Mountain Sickness (AMS)
The most common form, AMS, typically begins within the first 8 to 24 hours after arriving at altitude.
Symptoms can include:
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- Headache
- Fatigue or exhaustion
- Nosebleeds
- Dizziness or lightheadedness
- Loss of appetite
- Nausea + vomiting
- Insomnia or restless sleep
- Swelling of hands and feet
The most effective way to recover from altitude sickness is to descend to a lower elevation as soon as possible. If your symptoms are mild, staying at your current altitude while you rest and allow your body time to adjust can often help. Avoid strenuous activity and focus on hydration. In many cases, discomfort improves within one to two days without needing further treatment.
High-Altitude Pulmonary Edema (HAPE)
HAPE develops when fluids collect in the lungs as a response to lower oxygen levels at high elevations. This condition typically appears within 24 to 72 hours after ascending to altitude and can become life-threatening if not treated promptly.
Symptoms can include:
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- Severe cough that can progress from dry cough to coughing up pink, frothy mucus
- High heart rate
- Fast breathing
- Low fever
- Blue skin, lips, or nails
- Shortness of breath even with minimal activity
- Chest tightness, congestion, or pain
- Decreased exercise tolerance
HAPE is a medical emergency that requires immediate descent to a lower altitude and prompt medical care. As soon as possible, go to the nearest hospital that can provide oxygen therapy and has experience treating altitude-related conditions. Even if your symptoms start to improve after descending, seeking professional medical evaluation is essential.
High-Altitude Cerebral Edema (HACE)
HACE is swelling of the brain’s tissues, which develops 12–72 hours after ascent.
Symptoms can include:
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- Persistent headache
- Profound fatigue and weakness
- Lethargy
- Difficulty walking normally
- Loss of muscle coordination
- Confusion or trouble concentrating
- Dizziness and lightheadedness
- Loss of consciousness
HACE can be fatal and requires immediate descent and emergency medical treatment.
Tips to Prevent Altitude Sickness
If you’re visiting Boulder County or venturing up to Estes Park, the Indian Peaks Wilderness, or other high elevation destinations, preparation is key:
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- Ascend gradually—if possible, spend a night or two in Boulder (5,300 feet) before going higher.
- Ease into activities—start with light hiking or sightseeing rather than strenuous exercise.
- Stay hydrated—drink plenty of water and limit alcohol, especially in your first days at elevation.
- Know your limits—listen to your body and don’t ignore early symptoms.
- Talk to your doctor—ask about preventive medications like acetazolamide (Diamox) if you have a history of altitude sickness or plan a rapid ascent.
When to Seek Medical Care
Mild headaches and fatigue are common at high altitudes. However, if you experience severe shortness of breath, worsening confusion, or inability to walk steadily, seek medical care immediately. Altitude sickness can affect anyone—locals and visitors alike. Even healthy, active people can develop severe symptoms if they ascend too quickly or overexert themselves. If you feel unwell, don’t try to push through it. Rest, hydrate, and get medical help if your symptoms are severe. The mountains will still be here when you feel better.
About Boulder Medical Center
Boulder Medical Center is an independent, physician-owned multi-specialty practice that has been serving the health needs of our community for more than 75 years. With five convenient locations across Boulder County, our team includes primary care providers and specialists who work together to deliver comprehensive, patient-centered care.
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Disclaimer: This information is provided for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your healthcare provider with any questions you may have regarding a medical condition.