Are you a mountain lover? Is the thrill of scaling heights irresistible? Before you embark on your next mountain adventure, there’s something essential you must know. Altitude sickness can turn a breathtaking journey into a literal breathless ordeal. In this guide, I will draw from my decades of mountaineering experience to help you understand altitude sickness and how to mitigate its effects.

Understanding Altitude Sickness


Altitude sickness, often referred to as “mountain sickness,” is a combination of symptoms that may occur when you expose yourself to high altitudes, particularly above 2,500 meters (8,202 feet). The main culprit?

Reduced oxygen levels and air pressure changes that your body hasn’t had time to adapt to. This can lead to headaches, nausea, vomiting, dizziness, and fatigue.

But beware, it’s not just the mild discomfort. In severe cases, altitude sickness can cause life-threatening brain and lung complications.

The Underlying Cause

The primary cause of altitude sickness is ascending too rapidly. Your body doesn’t get ample time to adapt to the decreased oxygen and changes in air pressure at higher altitudes. Various factors like rapid ascents, dehydration, overexertion, and cold temperatures can contribute to it.

Fun fact: Did you know that at an altitude of 3,658 meters (12,000 feet), there is 40% less oxygen than at sea level? Imagine your body’s strain trying to adapt!

Symptoms to Watch Out For

Identifying the symptoms of altitude sickness is your first line of defense. They can range from mild headaches and nausea to severe complications such as High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE).

Acute Mountain Sickness (AMS) is the mildest and most common form. Here’s how you can categorize it:

  • Mild AMS: Mild headache, fatigue – not too bad, and your activities aren’t hindered. Give it a few days for your body to adjust.
  • Moderate AMS: Here, the symptoms start impeding your activities. You might experience severe headaches, nausea, and coordination problems. Descending is necessary to feel better.
  • Severe AMS: Shortness of breath even at rest and difficulty in walking. Immediate descent and medical attention are critical.

Altitude Sickness Complications

Severe types of altitude sickness can develop at exceedingly high altitudes. The two most severe types of altitude sickness are pulmonary edema (fluid in the lungs) and cerebral edema (fluid in the brain) (swelling of the brain).

High altitude pulmonary edema is known as “High Altitude Pulmonary Edema” (HAPE), while cerebral edema is known as “High Altitude Cerebral Edema” (HACE).

HAPE and HACE are potentially fatal conditions, and a steroid called dexamethasone can relieve symptoms until the affected person can descend to a lower altitude. Many of the lesser altitude sickness symptoms may be handled without descending.

This decline may generally be avoided with rest, medication to treat symptoms, and enough fluids to prevent dehydration.

High Altitude Cerebral Edema (HACE)

HACE is essentially the swelling of the brain due to a lack of oxygen. Symptoms include weakness, nausea, coordination problems, confusion, and hallucinations. HACE can develop rapidly and is life-threatening.

HACE Treatment:

  • Descend immediately to a lower altitude
  • Take dexamethasone (a steroid that reduces brain swelling)
  • Use supplemental oxygen if available

High Altitude Pulmonary Edema (HAPE)

HAPE is the accumulation of fluid in the lungs. Symptoms include cyanosis (bluish skin), breathing difficulties, chest tightness, a prolonged cough with pink or white foam, and extreme fatigue.

HAPE Treatment:

  • Descend immediately to a lower altitude
  • Take nifedipine (a medication that alleviates chest tightness and improves breathing)
  • Use supplemental oxygen if available.

Who is at Risk?

Altitude sickness can be an unwelcome companion to anyone, regardless of age, gender, or physical fitness. However, certain individuals are more susceptible:

  • People who ascend too rapidly
  • Those with a history of heart or lung diseases
  • People with low hemoglobin levels
  • People who are dehydrated or sleep deprived
  • People who engage in strenuous activities at high altitudes
  • People who stay at high altitudes for longer periods of time
  • People with weakened immune systems

How can you tell if you have altitude sickness?

You can recognize altitude sickness by a combination of symptoms that typically occur within 24 to 48 hours after reaching higher altitudes. The most common symptoms include headache, nausea, fatigue, dizziness, shortness of breath, and sleep disturbances.

If you have a headache along with one or more of these symptoms, you might be experiencing altitude sickness. If you start to experience any symptoms of altitude sickness, stop your ascent and descend immediately. Avoid strenuous activities and rest until you feel better.

How do you acclimatize to high altitudes?

Acclimatization to high altitudes involves a gradual process of adjusting to the decreased oxygen levels. Here are some guidelines for acclimatization:

  • Ascend gradually: Do not increase your altitude by more than 300 meters (980 feet) per day once you are above 3,000 meters (9,840 feet).
  • Sleep at a lower altitude than the highest point you reached during the day.
  • Stay hydrated by drinking plenty of water.
  • Avoid alcohol and tobacco.
  • Consider using medications like acetazolamide to help acclimatize faster.
  • Take rest days every 3,000 feet to allow your body to adjust.

Can medication help to prevent altitude sickness?

mountain hiking

Yes, medications like acetazolamide and dexamethasone can be used to prevent altitude sickness. These medications can help to alleviate symptoms and aid in acclimatization. Consult your doctor before taking any medications, especially if you have underlying health conditions.

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Conclusion: Be Prepared and Stay Safe

Embarking on a hiking adventure in the mountains can be an exhilarating experience. However, it’s crucial to be informed and prepared for altitude sickness, especially if you’re a beginner. Recognizing the symptoms and understanding the importance of acclimatization are essential in preventing and handling altitude sickness.

Being equipped with the knowledge and taking precautions will not only help you to enjoy the breathtaking views and the sense of achievement that comes with mountain hiking but also ensure your safety and well-being.

Always remember the golden rule: listen to your body. If you feel unwell, it’s best to take it easy, descend, and seek medical help if necessary. Happy trails!