What You Can’t Change

Before getting into training for high altitude, it’s worth being clear about the constraints.

At high altitude, the limiting factor is oxygen availability.

No amount of training at sea level will fully replicate that.  No fitness programme will make high altitude feel normal.

Some people are also more susceptible than others. Individual responses to altitude vary considerably.  Not everyone acclimatises at the same rate, even on the same itinerary.

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So, if you’re looking for a way to remove the problem entirely, it doesn’t exist.

But that doesn’t mean you’re powerless.

What You Can Influence

You’re not trying to “beat altitude.”

You’re trying to increase your capacity to work whilst at high altitude.

When people talk about altitude training, they are often referring to altitude tents and hypoxic systems, but the fundamentals are usually much simpler.

The fitter and more efficient you are, the less of your total capacity each step requires.

That’s how you create a reserve.  The five principles below give the biggest return on your training time. They are the areas I focus on before high-altitude trips.

One - Aerobic Base

If there’s one thing that consistently makes the biggest difference, it has to be aerobic base.

A strong aerobic base allows you to move more efficiently, recover more quickly between efforts and maintain a steady, sustainable pace for longer.

At altitude, that matters because spikes in effort are expensive. Every unnecessary surge increases oxygen demand at a time when oxygen is already limited.

The better your aerobic base, the more comfortable it becomes to operate at the sort of low-intensity effort levels that high-altitude travel often requires.

Improving your aerobic base is straightforward. Focus on long, steady efforts such as walking, hiking or uphill work at a conversational pace.  Typically this training should be within Zone 2, to build a strong foundation.  The key is consistency rather than intensity.

This is not hard training and it’s not glamorous, it’s the low intensity mundane work that is essential for a strong aerobic base.

If you aren’t up to speed with heart rate zones and what Zone 2 means, then a good starting point might be this British Heart Foundation article followed by this Harvard Health piece about understanding exercise heart rate zones.

Two - VO2 Max

If aerobic base determines how efficiently you can work for long periods, VO₂ max represents the size of the engine available to you when effort levels increase.

While aerobic base is the foundation, your upper capacity or VO₂ max, still plays a significant role.

Altitude reduces everyone’s VO₂ max. However, starting with a larger aerobic engine means you retain more usable capacity as you go higher.

As altitude increases, preserving usable aerobic capacity becomes increasingly important on peaks such as Mera Peak and Aconcagua, where reduced oxygen availability places significant demands on the body.

If your maximum capacity is higher, the same workload represents a smaller percentage of it.

That gives you more room for manoeuvre before breathing becomes laboured and effort levels begin to feel unsustainable.

You don’t need to train like a professional athlete, but some higher-intensity work, such as intervals or sustained uphill efforts, can help raise that ceiling.

You can learn more about VO₂ max in this useful Harvard Health article.

Three - Muscular Endurance

Altitude isn’t just about heart and lungs, it’s about whether your legs can keep working, under load, for long enough.

If your legs fatigue early, your movement becomes less efficient, your breathing rate increases and, in turn, your heart rate rises.

These factors push you closer to your limit faster.

Useful training includes long uphill days with a moderately heavy pack. Step-ups, hill reps, squats and leg press work can also help.

Don’t just focus on the legs though.  Whilst legs are a key component and essential for upward movement in the mountains, neglecting the other elements of your body will lead to an imbalance, your strength and muscular endurance training should focus on the whole body.

Four - Pacing Discipline

The first three elements are relatively straightforward.  Pace discipline, the ability to select an appropriate pace and stick to it, is where a lot of people come unstuck.

These principles are just as relevant on a trek such as Everest Base Camp as they are on a climbing objective.  On mountains like Kilimanjaro, pacing errors often destroy summit success.

Perhaps though, there is a lack of understanding of what constitutes an appropriate pace.  This is where we link back to our aerobic base.  An appropriate pace is not necessarily a super slow pace but as you go higher it will naturally be slower.  I find the best guide to this is my heart rate.  So long as I’m keeping my heart rate firmly within Zone 2 then the pace will be about right.  If I edge towards the top end of Zone 3 then I’m working too hard.  Longer term that’s not going to do me any favours.

In my experience, fit individuals struggle with this the most at altitude.  Often they will go too fast too early, surge their pace, pushing their heart rate up into Zone 3.  They will feel ok whilst they are pushing but generally fail to recognise the downstream effects.  It’s common for the consequences of overexertion to become apparent only after you’ve arrived at your sleeping altitude.  Quite often, symptoms of AMS don’t start to show until 6 to 12 hours later.

At altitude, listening to your body is key, slow is efficient, steady is sustainable and surging is costly.

This isn’t just physical, it’s behavioural and it’s one of the biggest differentiators I see between those who cope well and those who don’t.

Five - Acclimatisation

No amount of training replaces a good itinerary.  The fundamentals of a gradual ascent, controlled increases in sleeping altitude and proper planned rest days remain key to success.

Guidance from specialist bodies such as the Wilderness Medical Society is clear on this: ascend too quickly and your risk increases, regardless of how fit you are.

Choosing an itinerary with appropriate acclimatisation days remains one of the most important factors in high-altitude success.

Our Mera Peak itinerary includes a dedicated stop at Mera Base Camp before moving to High Camp, helping maximise acclimatisation before the summit push.

Training builds capacity.

Acclimatisation allows you to use it.

So, Can You Extend Your Limit?

Yes.  You totally can.  Some focused training before going to altitude can help you move more efficiently, tolerate effort better and delay the point at which things become unsustainable.

But you can’t remove the limit entirely.

At some point, for everyone, the margin runs out.

Next Steps

If you’re planning a high-altitude trek or preparing to climb a peak above 5,500m, keep it simple and focus on what actually makes a difference.  Here are seven actionable points:

1. Build a base first: Aim for consistent, steady training 3 to 4 times per week.  Long walks, hikes, or uphill sessions are far more valuable than occasional hard efforts.

2. Add some intensity, but not too much: One session a week where you push a bit harder (intervals, hills) is enough to raise your ceiling without burning you out.

3. Get used to moving under load: You’ll likely be carrying a pack whilst on your trip so train with one.  Start light and build up gradually.

4. Spend time on your feet: There’s no shortcut for this.  The more time you spend walking, especially on uneven ground, the more efficient you’ll become.

5. Practice going slower than you think you should: This is one of the most underrated skills.  Get used to monitoring your heart rate, staying in Zone 2 and learn what a sustainable pace actually feels like.

6. Don’t try to shortcut acclimatisation: No amount of training replaces time spent at altitude.  Choose itineraries that follow the Wilderness Medical Society guidance and allow plenty of time plus some spare days for flexibility.

7. Keep perspective: You’re not trying to eliminate difficulty; you’re trying to give yourself enough reserve to deal with it.

What About Altitude Tents and Hypoxic Training?

You’ll come across altitude centres and hypoxic training setups that simulate reduced oxygen environments before a trip.

On the face of it, the logic makes sense, expose the body to lower oxygen, trigger adaptation, arrive better prepared.

There’s likely some benefit there.

But in practice, it’s worth keeping it in perspective.

The adaptations you get from short-term hypoxic exposure are relatively modest, and more importantly, they don’t last indefinitely.  By the time most people actually reach meaningful altitude on a trek or expedition, any early gains may already have reduced or disappeared.

That doesn’t make it pointless, it just means it’s not a substitute for a well-paced itinerary or proper acclimatisation on the mountain.

Where these setups can be genuinely useful is in the training itself.

If using a reduced oxygen environment helps someone train more consistently, push their aerobic system and get used to feeling uncomfortable then there’s clear value in that.

But it’s worth understanding where the real benefit is coming from.  For most people, the biggest gains will still come from building a solid aerobic base, increasing VO2 max, improving strength and endurance and learning to maintain an appropriate pace.

Hypoxic training might sit on top of that but in my opinion, it doesn’t replace it.

The Bottom Line

The goal isn’t to become immune to altitude and at any rate, that’s not possible.

The goal is to give yourself as much room as possible to operate safely whilst at altitude.

Better fitness doesn’t make the mountain smaller, but it does give you a slightly bigger more efficient engine to work with when you get there.