What Is Mountain Sickness And Why Does It Happen?

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So what is mountain sickness and why does it happen? Also known as altitude sickness, mountain sickness is characterized by common symptoms that occur when you ascend to higher altitudes too quickly.

At higher elevations, the concentration of oxygen molecules in the air you breathe decreases. As a result, your blood does not carry sufficient oxygen to your body and vital organs.

Hence, this critical molecule for sustaining life is diminished. The result? Dizziness, nausea, general malaise, shortness of breath, and exhaustion, to name just a few symptoms.

A couple of years ago The Geez experienced something unusual. To begin with, when summiting Kaiser Peak, I had trouble breathing after hiking above 9,000 ft.

That had never happened before. I ended up descending to a lower elevation and breathing returned to normal. But that was not the only time.

On two subsequent occasions, I experienced several other classic symptoms. For example, while backpacking to Rae Lakes in Kings Canyon National Park I had headaches, dizziness, and nausea.

This scared the crap out of me. I was hiking on a narrow ledge on the side of a cliff and had never experienced these problems before. It must be true what they say, age is the great equalizer!

Three Levels of Altitude Sickness

  • Acute mountain sickness (AMS)
  • High-altitude pulmonary edema (HAPE)
  • High-altitude cerebral edema (HACE)

AMS is the most common and the least dangerous of the three syndromes. Usually, it strikes at elevations of about 8,000 ft.  Its symptoms are generally mild and manageable.

On the other hand, HACE and HAPE do not occur nearly as frequently. However, they’re more life-threatening, especially for older hikers. Some of their symptoms include drowsiness, confusion, increased breathlessness, weakness, and even death. 

Causes of Mountain Sickness

As I already mentioned earlier, mountain sickness occurs when you climb too rapidly before your body can adapt to the changing environmental factors. At sea level, the concentration of oxygen stands at about 21 percent.

While this percentage doesn’t change at higher altitudes, the number of molecules per cubic meter of air decreases significantly as altitude increases. It’s estimated that at 18,000 ft, only about half the amount of oxygen available at sea level enters the lungs with each breath you take in.

To compensate for this oxygen deficit, your heart pounds faster and your breathing rate increases. In short, the body tries to raise oxygen levels in the blood by every means possible.

Older adults tend to struggle more with this problem. As a result, extra caution is needed when you’re hiking at altitudes above 8,000 ft.

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Additional Mountain Sickness Alerts

Also at high elevations, fluids can start to leak from tiny blood vessels. This can cause fluid buildup in critical body organs like the lungs and brain. If the situation is not managed correctly, this problem can result in life-threatening conditions or even death.

The use of alcohol, tobacco, and steroids has also been found to trigger or accelerate mountain sickness. These substances, combined with less oxygen, lower your brain’s ability to coordinate body processes.

Therefore, your ability to acclimatize quickly may be reduced. Steer clear of these substances, especially during the first 48 hours of starting to hike at high altitudes.

Studies show that your genetic makeup may also increase the likelihood of experiencing mountain sickness. For example, deficiencies related to the SENP1 and ANP32D protein-coding genes are quite common among people who get altitude sickness.

what is mountain sickness and why does it happen on a background of the clouds and sky

Mountain Sickness Acclimatization Tips

Acclimatization is the process of letting your body gradually get used to environmental changes; in our case, the barometric air pressure is reduced as you climb to higher elevations.

Hikers and backpackers who fail to acclimatize properly to new elevations have the highest risks of getting mountain sickness.

The body needs time to adjust. Normally the human body takes between 2-3 days to adapt fully adapt to change in altitude. However, older hikers can take longer depending on their age, health status, and prior exposure to similar elevations and experiences.

During a hike to Rae Lakes in Kings Canyon National Park this past last year, The Geez was forced to slow down after I developed classic altitude sickness symptoms midway.

Rae Lake California steep mountain with a tree, lake, and rocks.
Middle Rae Lake California
To overcome the obvious AMS symptoms, we had to discontinue hiking to higher elevations and remain at the middle Rae Lake where we spent a non-hike zero-day at camp.

Most importantly, I now have a prescription for altitude sickness medication and carry it with me on every hike.

Tips for Higher Elevations on the Trail

If you are a hiker over 50 and looking for practical ways to ease the process of getting used to higher elevations, here are a few useful guidelines you can follow:

  • Always start your hikes at altitudes not exceeding 10,000 ft. Even when you drive or fly to a high-altitude area, be sure to incorporate a layover of at least a day at that or an intermediate elevation.
  • Drink plenty of water and increase the amount during hot and dry days. Depending on the prevailing weather conditions and the pace at which you are hiking, drink at least one liter every one to two hours. I also recommend adding some electrolyte tablets or powder to your water to replace lost sodium, magnesium, and potassium. It makes a tremendous difference in how you feel.
  • Never ignore signs of altitude sickness, no matter how mild they may appear. Whenever you start feeling or acting strange, take proactive measures. For example, moving to a lower elevation. If you are prone to altitude sickness, take medication before you start your hike.
  • As a rule of thumb, climb high and sleep low. Be aware that over 8,000 ft. elevation, every time you ascend more than the recommended 1000 ft. per day the probability of altitude sickness increases. The idea is to move to a lower elevation to pitch camp after a long day on the hiking trail at higher elevations.


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Diagnosing Mountain Sickness

As is the case with any other ailment, the diagnosis of altitude sickness depends on the signs and symptoms exhibited by the hiker. Earlier on, I explained the three levels of this condition and even outlined how each manifests itself.

In most cases, all you need is to move to a lower altitude when mountain sickness strikes to allow your body to acclimatize. Additionally, you can take over-the-counter (OTC) medications like acetaminophen, ibuprofen, or aspirin to stop headaches.

On the advice of your doctor, you can also use antiemetic drugs like prochlorperazine and ondansetron to deal with nausea. These medications also heighten your breathing rate, thereby leading to increased uptake of oxygen when in high-altitude areas.

If you have a prior history of altitude sickness, your doctor may prescribe acetazolamide to hasten acclimatization. The drug, which is a diuretic, seeks to increase the excretion of bicarbonate by the kidneys. This lowers your blood pH and, as a result, increases your breathing rate to boost oxygen levels in the blood.

However, be extremely careful about dehydration. Any medication that has a diuretic effect can be dangerous to older hikers. That is to say, between sweat, heavy rapid breathing, and diuretic medication it is easy to become dehydrated. If you are an older hiker, check out my post for additional life-saving tips rarely mentioned.

So, what happens when something worse like HACE or HAPE occurs? The first course of action should be to call for emergency services, particularly if the affected person loses consciousness or is immobile.

Be sure to carry a satellite messaging device or satellite phone for such an emergency when out of cell phone range. In the meantime, oxygen should be provided if available.


Other Altitude Sickness First Aid Tips

Other first aid tips to consider include:

  • Administer an antibiotic if the affected hiker has a fever or shows signs of pneumonia infection.
  • A steroid like dexamethasone has also been found to offer temporary relief for people suffering from HACE. It’s worth noting that some hikers may feel like they’re ready to continue climbing after using this drug. However, that should be discouraged as it can be life-threatening. Also, never take any medications without the advice of your physician.
  • Ultimately, descending from the current altitude is the only definitive treatment for all forms of mountain sickness. Most importantly, for severe cases like HAPE and HACE, this should be followed with a visit to the doctor for further checks and direction. Usually, the doctor will carry out examinations for fever, oxygen saturation in the blood, heartbeat rate, abnormal sounds coming out of the lungs, and mental state in the case of HACE.

Chronic vs. Acute Mountain Sickness – What’s the difference? Monge’s disease is the medical name for chronic mountain sickness. It develops after you spend an extended time at an altitude of over 3000m (approximately 9840 ft.) On the other hand, acute mountain sickness occurs after climbing too fast to a high elevation, usually above 8,000 ft.

Who can develop mountain sickness? Anyone can develop this condition. That is to say, regardless of age, fitness level, or gender. In short, your risk increases depending on how quickly you ascend to a higher altitude, the altitude at which you sleep, and how high you go.

Many older hikers with illnesses like high blood pressure and lung diseases are more likely to get altitude sickness compared to their younger counterparts.

How long does altitude sickness last? This depends on the severity of the condition. For example, acute mountain sickness can often go away as soon as you descend to a low-altitude area.

For other safety tips for older hikers make sure and check out my post 21 Simple Survival Tips for Hikers Over 50.

Hike safely, my friends!

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