What Is Considered High Altitude Hiking? (And How To Stay Safe)

The towering peaks of the mountains call to many of us that love the great outdoors. But not all adventurers know what is considered high altitude hiking, and there are important precautions to bear in mind to ensure you stay safe when hiking the tallest peaks.

High Altitude hiking is considered to be any hiking 8,000 ft (2,400m) above sea level. With some prior acclimatization and precautions, hiking above 8,000 ft can be done safely by most people in good health.

Prior preparation and acclimatization is essential for any hike above 8,000ft, and as altitudes increase to very high and extremely high elevations, the necessity of these preparations becomes more and more important. Below, we’ll take a closer look at each of these precautions.

What Counts As ‘High Altitude’?

While high altitude might sound like a vague term, when it comes to hiking there are very real differences between different elevations. For someone who lives at or near sea level these differences will be more noticeable. Hiking as low as 4,000ft could cause some who are not used to altitude to struggle.

High altitude, above 8,000ft, is the zone where almost everyone is going to feel some effects of the elevation and should begin to take precautions to ensure that their hike is successful.

High Elevation

High elevation is between 8,000 and 12,000ft (2,000m-3,650m). This is the level where the effects of the thinner air become noticeable, but the risk for problems is the lowest (of the three levels of altitude considered in this article). Following basic precautions should keep most people safe at these heights.

Many peaks in North America fall into this range and should be climbable for most people in good health.

Very High Elevation

Very High Elevation is any altitude between 12,000ft and 18,000ft (3,650-5490m). At these altitudes almost everyone will feel the effects of the thinner air and precautions are essential.

High altitude acclimatizing prior to ascent and ascending slowly become even more necessary the higher into this zone you climb. Understanding your body and knowing the symptoms of altitude sickness is also key here.

Most of the highest peaks in North America are in this zone, with Mt. Whitney, the tallest in the Lower 48, clocking in at 14,494ft (4,418m).

Extremely High Elevation

Extremely High Elevation is above 18,000ft (5490m). In this zone the dangers associated with altitude become serious and climbers must approach this zone with caution. At these heights mistakes can easily prove fatal and so you need to proceed with extreme caution.

All climbers will experience the effects of the altitude up in this zone, and as they ascend further the potential for Acute Mountain Sickness and the far more serious High Altitude Pulmonary/Cerebral Edema become more real.

Few mountains in North America reach this height, Denali being a famous exception. If you plan on hiking in the Himalayas or the Andes, though, peaks of these attitudes are far more common and climbers should come prepared.

General Precautions For Any High-Altitude Hike

Anytime you climb over 8,000ft, even if you are an experienced climber, the effects of the elevation will impact your trip. The thinner air, higher UV radiation, and unpredictable weather will become issues and the only real solution is to be properly prepared.

Always Acclimatize

When we arrive at a national park or a beautiful mountain range, often all we want to do is hit the trails. This instinct must be ignored if we want to tackle the higher mountains successfully. Acclimatizing to the altitude is key before any high-altitude hike.

There are no exceptions to this rule either. Fit, healthy, experienced climbers can struggle with altitude sickness. The only solution is to take some time to let your body produce the extra red blood cells you are going to need for your climb.

The higher you plan on climbing, the longer and more frequently you will need to stop to acclimatize. A good rule of thumb is a minimum of 3 days at 8,000 ft or above before you climb, only climbing 1,000 ft (330 m) per day, and an extra rest day after every 3,000 ft (1000 m) in elevation gain.

Climb High, Sleep Low

Experienced climbers in snowy refuges around the world will repeat the mantra‘climb high, sleep low.’ What this means is that you should climb above the altitude at which you plan on sleeping. A common recommendation is a minimum of half an hour at least 300 ft (100 m) above the altitude where you will sleep.

Spending time above your sleeping altitude, even if it is just sitting to take in the views, will be an enormous help when climbing at these high elevations. It essentially allows your body to gradually get used to higher altitudes, while resting at an altitude your body has already adjusted to.


Perhaps the most important step during your climb is hydration. 3-4 liters of water, roughly 3-4 quarts, per day is highly recommended for any climb. Remember that an ascent is physical exertion at high altitude, so your body is going to need all the water it can get. The dry air of the mountains will dry you out too.

Don’t worry about frequent bathroom breaks, it is usually a good sign. Remember what coaches around the world have said for years: “Pee clear and you’re in the clear.”

Prepare For The Elements

One of the most important things you can do to prepare for a climb is to make sure you have the proper clothing and equipment for the trail. High altitudes require more attention to detail than lowland hikes, and preparing properly will lead to a much more enjoyable hike.

Dress Properly

Just as in business, dressing for success is a must when taking on high altitude hikes. The higher you go, the colder it gets. Exposed areas are windy, and blue skies can turn to rain quickly. Wearing the proper clothes for your hike will often mean the difference between a great hike and a miserable one.

What clothes you will need will greatly depend on the climb you are attempting. Proper research is essential and extra preparation is recommended.

UV Protection

The higher you climb the thinner the air gets, which means fewer air molecules to block the Sun’s rays. This can be nasty for the skin and the eyes, and can cause serious discomfort. Anti-UV clothes and sunglasses, as well as high SPF sunscreen is a must, and is recommended for all high-altitude hikes.

Watch The Weather

The higher you go in the mountains the more of an issue the weather will become. Beautiful days can turn into storms faster than you think, and often you only realize exactly how exposed you are when the wind picks up.

The easiest way to prevent weather related issues is to check multiple forecasts and take a very conservative attitude about climbing. ‘Iffy’ or ‘possibly bad’ weather is not your friend. It is far, far better to wait a day than to risk climbing in bad weather.

Prepare For The Unexpected

One of the leading causes of injury and death at high altitudes is an unexpected shift in weather. It is not rare to be prepared and have a great forecast, only to have blue skies turn violent with mere moment’s notice. The best way to stay safe is to prepare for unexpected weather. Pack rainproof gear, take extra warm clothes, and have emergency plans in case the weather shifts.

Unexpected shifts in the weather should be treated with great caution. All of us want to reach the peak, and a surprise storm can put a quick stop to that. It is extremely important that you do not risk it. It is far better to descend and try for the summit another day than risk injury – or worse.

How To Safely Hike At Very High Altitudes

As you climb above 12,000 ft all of the issues present at lower altitudes become more serious, and you must take further precautions. Prior acclimatization is absolutely necessary for almost all hikers. It is important at these attitudes to be sure to not push your limits. Only ascend 1,000 ft (330 m) per day, and have a rest day every 3,000 ft (1,000 m).

Hiking Above The Tree Line

Depending where you are in the world, these altitudes will often be above the tree line. Here there is far less protection from the elements and climbers have a lot more to contend with.

Wind, rain, and harmful UV are all significantly more intense and so you need to properly prepare for them. Sudden changes in weather also become more dangerous. There is much less cover should a storm roll in, and you need emergency plans to stay safe.

Acute Mountain Sickness

Above 10,000 ft (3,050 m) almost all hikers will experience some form of Acute Mountain Sickness. Normally the symptoms will be mild, and a slower pace and extra rest days should help most people recover.

Mild symptoms will include dizziness, shortness of breath, fatigue, and mild nausea. These are all normal and usually not serious, but should be taken seriously and monitored regardless.

More severe cases will see hikers act drunk, have trouble catching their breath when resting, and vomiting and dizziness are common too. When the case is severe you need to descend. For some, a few hundred feet of descent will help them recover. For more serious cases the affected person will need to descend several thousand feet.

This is a serious condition and not something to be taken lightly. It can strike the most experienced climbers and the best way to stay safe is to be cautious.Know your body and take all symptoms seriously.

How To Safely Hike At Extremely High Altitudes

Extremely high altitudes involve any hike above 18,000 ft (5,500 m). At these heights all of the issues present at lower altitudes are present and often present in much more serious forms. These elevations are often dangerous and should only be attempted by experienced climbers. Hiring a reputable guide is also highly recommended for any hike above 18,000ft.

Knowing Your Limits When Hiking

The best way to avoid having problems at extremely high altitudes is not to climb that high if you don’t have enough experience. These elevations are not for beginners and shouldn’t be undertaken on a whim. This is serious climbing and should only be done by experienced, serious climbers.

We all want to climb higher and trek further, but knowing your limits and not attempting something beyond your ability is the best way to prevent injury.

High Altitude Pulmonary Edema

At this extreme altitude, altitude sickness can become something significantly worse, like High Altitude Pulmonary Edema, or HAPE. HAPE results from fluid building up in the capillaries of the lungs. The symptoms are confusion and impaired mental function, shortness of breath at rest, and coughing up white fluid.

HAPE is extremely serious and the affected person must descend to lower altitudes and seek immediate medical attention.

High Altitude Cerebral Edema

An even more serious issue that can arise at extreme elevations is High Altitude Cerebral Edema, or HACE. This is a life-threatening condition that is caused by swelling of the brain. Loss of consciousness is common, as are psychotic behavior, and hallucinations.

A person with HACE will die if they do not immediately descend and seek medical treatment. This is a matter of life and death and is not to be taken lightly. Many experienced hikers have lost their lives to HACE.

Final Thoughts

Hiking at high altitudes can be an immensely rewarding experience. The vistas, the clean mountain air, and the feeling of accomplishment standing on the summit are all worth the effort to get up the trail. These treks, though, do come with some risks. With proper precautions, though, hikers can safely enjoy their climbs and return to tell the tale.