Exercising at high altitude: how to adapt in the first few days

Exercising at high altitude calls for a different approach than at sea level: in the first days you need to cut back and give your body time to adjust. This applies not only to hiking and mountaineering but to ordinary trips too — many people end up at altitude for work or on vacation: high cities in Latin America, mountain resorts, summer camps. And almost everyone notices the same thing: you get out of breath sooner, your heart rate is higher and your usual pace feels impossible.

Why is it harder to exercise at high altitude?

The higher you go, the less oxygen you get with each breath, and your body needs time to adjust. The CDC states plainly that maximum exercise capacity at altitude is always lower than at sea level — even for well-trained people.

So a slow pace in the mountains isn't a sign of poor fitness. Comparing yourself with your results at home in the first days is pointless: different conditions, different numbers.

• Your heart rate at rest and during exercise may be higher than usual.
• Shortness of breath comes sooner, especially on climbs.
• Sleep can be lighter for the first few nights.

Are there benefits of exercising at high altitudes?

There are, but for most people they're not about "altitude training" — they're about moving in the fresh air. For athletes, altitude is a well-known tool, but it requires a plan and supervision by specialists.

For a traveler, the goal is more modest and more enjoyable: keep the habit of moving without overloading your body while it adapts. Walks on mountain trails, easy runs on a flat road, stretching with a view of the valley — all of this supports fitness and mood. Read how nature affects stress and sleep in "Walking in nature".

How to exercise at high altitude in the first few days

The first two days are the most important: during this time it's best to move gently and rest a lot.

• First 48 hours — only gentle activity: walks, light stretching. The CDC recommends this for anyone sleeping above about 2,450 m (8,000 ft).
• During those same two days, skip alcohol and hard workouts — this is one of the basic recommendations for travelers.
• If you're heading even higher on a hike, don't go from sea level to above 2,750 m (9,000 ft) in a single day, and then raise your sleeping altitude gradually.
• Lower your pace and volume: go by how you feel and your breathing, not by the usual numbers on your watch.
• Drink water throughout the day and take a bottle to your workout — more on hydration in "How much water do you need to drink".

How do you return to your usual workouts after adapting?

Return gradually, adding a little volume or intensity at a time and watching how you feel the next day.

• First increase the duration of easy exercise, and only then the pace.
• Alternate active days with lighter ones.
• If fatigue lingers after a workout or you sleep worse, make the next day an easy one.
• An easy run at a "conversational" pace works well at this stage — more in "Zone 2 cardio".

How should you plan a trip to a high city like Mexico City if you train regularly?

Pack your usual shoes and gear, but plan your first days as "easy" ones: walks around the city instead of intervals. If you're preparing for a hike, the tips in "How to prepare for mountain hiking" and "Preparing for a hike: water and effort" will help.

Once you've adapted and want to return to full workouts, some athletes bring the X49 patch — according to the company, it's designed for endurance in active people. And for steady energy on the road without caffeine, there's Energy Enhancer. But in your first days at altitude, your best helper is patience.