How to Prevent Altitude Sickness While Hiking

For those of us who love to travel and explore the mountains wherever we go, it’s important to be aware of what altitude sickness is, what causes it, and how to prevent it. Altitude sickness (also called “mountain sickness”) is a temporary condition caused by reduced oxygen levels available in the air in low barometric pressure environments.

In other words, when we find ourselves at altitudes significantly higher than what we’re used to — altitude sickness starts becoming a risk above 2,500 meters (8,000 feet) — our bodies struggle to adjust to the drop in pressure and can suffer from decreased oxygen levels. This can cause light-headedness, nausea, dizziness, headaches, fatigue, and even vomiting.

I was unlucky enough to experience altitude sickness in Kyrgyzstan while hiking at 3,900 metres on the Ala Kul Pass. Thankfully my case wasn’t severe, but it did make the final part of the ascent desperately hard work, and I woke up in the night with heart palpitations several times.

It’s safe to say that no hiker wants to deal with any of these symptoms while trekking in a gorgeous mountain range or tackling a long-sought peak, so let’s take a look at how to prevent altitude sickness while hiking.

What is altitude sickness?

Altitude sickness is a condition that strikes when we ascend to an elevation our bodies aren’t used to. The decrease in barometric pressure creates reduced oxygen availability in the air, and our bodies can struggle to catch up. This can lead to symptoms such as dizziness, fatigue, headaches, nausea, or vomiting.

For those who live year-round at higher elevations (in places like Santa Fe, New Mexico, or Cusco, Peru), their bodies adjust over time and get used to the low pressure and reduced oxygen availability. But for those of us who live much closer to sea level, it takes some preparation and mindfulness to prepare ourselves for high-altitude ascents.

Before we dive in any further, it’s important to remember that there are multiple different types of altitude sickness — acute altitude/mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE).

HAPE and HACE are both severe, dangerous, and potentially life-threatening conditions. Medical attention should be sought immediately if anyone is suspected of having these more severe types of altitude sickness. (Alex over at Lost With Purpose has a detailed account of her harrowing experience with HACE here, and Karl Watson’s Quest for Everest vlog shows his friend Chris in hospital with HAPE).

Acute altitude sickness on the other hand is mild, common, and more of an uncomfortable inconvenience than a dangerous condition. For the purposes of this article, I will be focusing on acute altitude sickness.

How to recognize altitude sickness

As altitude sickness is caused by a lack of oxygen in the body, the symptoms can feel similar to anything else that might deprive our brains or bodies of this critical element. For example, the way altitude sickness feels is sometimes compared to the feeling of a hangover.

The symptoms of altitude sickness are unmistakable and easy to spot. Anytime you’re hiking at or above an elevation of 2,500 meters (8,000 feet), it’s important to pay attention to your body and watch out for the signs.

Symptoms of altitude sickness include:

• sudden headaches
• dizziness
• nausea and/or vomiting
• sudden fatigue or loss of energy
• shortness of breath
• loss of appetite
• increased heart rate and/or heart palpitations

If you’re on a multi-day trek and sleeping at high altitudes, it’s also important to pay attention to any symptoms that might arise during the night, as trouble sleeping can also be an early sign of altitude sickness.

How to prevent altitude sickness

The best way to deal with altitude sickness is to prevent it altogether. Luckily, preventing it is fairly easy as long as you follow a few basic rules. So before we talk about what to do if any of these symptoms ever arise when you’re out on the trail, I’ll go over some tips on how to prevent altitude sickness in the first place.

1) Ascend slowly

The best way to prevent altitude sickness is to make sure you’re pacing yourself as you ascend. While it can be tempting to power up the mountain and summit as early in the day as possible, this can end up causing our bodies trouble when we’re hiking at higher elevations. Pace yourself, take breaks, and embrace the slow and steady. (Bonus tip: it can be especially helpful to go extra slow during the first 24 hours of an ascent.)

2) Give yourself time to adjust

Regardless of where your starting point is, it’s good to give yourself a few days at base camp to adjust before ascending above 2,500 meters. Of course, we can’t always time our ascents perfectly, but as a rule, it’s good to avoid things like flying directly into high-altitude zones from low-altitude zones or climbing more than 500 meters per day. If you have your sights set on doing a certain high-elevation ascent as a day hike, consider what it would take to adjust your plans to stretch that trek out over a few days instead.

3) Take days off

When tackling a multi-day climb at a high elevation, it’s essential not to hike every day. Taking one day off for every 900 meters gained in height (or every 3-4 days if you’re not tracking elevation that closely) is a good rule. Use that time to soak in the views, observe the wildlife, or just get some good rest.

4) Drink lots of water

That’s right: something as simple as making sure that you’re drinking enough water can help prevent altitude sickness. This is because water helps our bodies transport oxygen and other essential nutrients to our brains, and when we’re hiking at high elevations, we need all the oxygen we can get. Plus, drinking enough water while we’re hiking will help our bodies in myriad other ways, keeping us focused, energized, and resilient on the trail.

5) Make sure to eat enough calories

We all know how easy it is to eat light on the trail. Packing in all the food we need can be a nuisance when we’re trying to think of any possible way to lighten our packs. But the truth is, eating enough food (especially high-calorie foods) can mean the difference between having an amazing time in the wilderness or hiking with a headache and nausea. Not to mention that eating too little while doing extreme exercise can lead to low blood sugar, which can bring about many of the same symptoms as altitude sickness. To prevent both, try to eat between 1,500 and 2,000 calories per day.

How to deal with altitude sickness

While taking precautions will drastically reduce the risk, altitude sickness can always strike, no matter how careful you are. So if you start experiencing symptoms of altitude sickness, what should you do?

The most important thing is to stop hiking. In fact, you should stop moving or exercising altogether. Find a place to sit, tell anyone you might be hiking with what you’re experiencing, and take some time to assess the situation.

For at least 24 hours from the time you start experiencing symptoms, it’s important not to gain any more elevation. Take that time to drink lots of water, rest, eat high-calorie foods, and monitor your symptoms. If you’re still feeling ill after 24 hours, try descending at least 500 meters (1,600 feet), and give yourself another full day to rest there.

Once you’re feeling completely better, it’s safe to keep going. Remember to take your symptoms seriously and not brush them off. Even though acute altitude sickness is often mild and not particularly dangerous, it can become much more serious if early symptoms aren’t addressed and you continue to push on up that mountain. Take the time to rest and go at the pace your body can handle, then enjoy the rest of the ascent once you’re back in top form.

In conclusion

To sum up, the key to preventing altitude sickness is to go slow, go slow, and go slow! Pacing yourself, taking your time, and giving your body the time it needs to adjust are the most important methods for preventing altitude sickness.

It’s also vital to ensure you keep your body fuelled with enough water, nutrients, and calories to give yourself an even better shot at having an exclusively good time in the mountains.

If you follow all of these basic, easy steps, it will help immensely in preventing altitude sickness while hiking.

More hiking tips & guides 🥾

• See my Hiking Hub for all my hiking content
• How to plan your first multi-day hiking trip
• What to pack for a hiking trip
• My favourite hiking apps

Thank you for reading! If you found this post useful, I’d be grateful if you would consider using the affiliate links below when planning your travels. I’ll make a small commission at no extra cost to you. This will help me to keep this blog running. Thanks for your support — Lauren.

Accommodation – Booking.com
Flights – Booking.com
Travel insurance – World Nomads
Excursions & tours – Viator
Outdoor gear – Decathlon
eSIMs – Airalo

Alternatively, you could buy me a coffee to say thanks!