Altitude Training: Strategies for Running High Above Sea Level

Whether you're preparing for a high-elevation race or seeking an extreme challenge, training at (or simulating) altitude can unlock serious performance gains. This guide breaks down everything runners need to know about altitude training, from the science-backed benefits to how to reap its rewards.

What is High Altitude Training?

High altitude training, or ‘hypoxic training’, means training at elevations 2,000 meters above sea level or higher. At these heights, the air is thinner and contains less oxygen, making it harder to breathe. This environment forces the body to adapt, and those adaptations can lead to improved endurance and performance.

Why Train at Altitude?

Although altitude training was known about, it wasn’t until the 1968 Mexico City Olympics – held at 2,240 metres above sea level – that the benefits were widely recognized. The games highlighted that training in low-oxygen environments could greatly enhance athletic performance. Since then, sports science advanced, and so did the understanding of altitude training and how it can help elite athletes.

Acclaimed runners Shalane Flanagan, Galen Rupp, and Gwen Jorgensen have been known to favor high-altitude environments, like Colorado and Utah. And many runners are now training at high altitudes to get the benefits for themselves.

What Are the Benefits of High Altitude Running?

Exercising at elevation feels different for everyone. It will suit some runners more than others. And how to get the most from high altitudes is still being studied. That said, two significant, proven benefits are:

1. Increased Red Blood Cell Production

At high altitudes, the air contains less oxygen. In response, the body produces more erythropoietin (EPO), a hormone that helps make more red blood cells. And the more red blood cells, the more oxygen can be delivered to the muscles. Leading to…

2. Improved VO2 Max

With more oxygen reaching the muscles, the body becomes more efficient at creating energy during exercise. This leads to an increase in VO2 max – the maximum amount of oxygen the body can use during intense exercise. A higher VO2 max translates to better endurance and overall performance.

Who Benefits from Altitude Training?

While altitude training is most accessible to professional athletes who can temporarily relocate, anyone who does these sports will benefit:

• Marathon and distance runners

• Triathletes and cyclists: 

• Cross-country skiers

• Swimmers

Because it helps increase the body's aerobic capacity and oxygen delivery to muscles. 

How to Train and Perform at High Altitudes

It’s not possible to just ‘show up’ to a high altitude run. It requires planning and preparation. Here are 7 ways to get ready:

1. Aerobic Work

A strong aerobic base is key. Increase your aerobic base with moderately intense running or other forms of cardio that raise the pulse to 50–70% of your maximum heart rate (MHR).

An individual's MHR is estimated by taking away their age from 220, says the American Heart Association. Use this estimate to then work out your ‘target heart rate zone’ for moderate and vigorous cardio work.

As an example, a 40-year-old would have a MHR of 180 (220 - 40 = 180)

Moderate Exercise

This target heart rate zone for moderate exercise is 50–70% of your MHR. When exercising at this intensity, you can talk but might be slightly breathless.

A 40-year-old would average 90–126 beats per minute during moderate exercise.

Pushing it Further

Build up your base gradually. Once doing this, look to add vigorous exercise like interval training and hill sessions to your training. High-intensity interval training (HIIT) improves the body's ability to process oxygen, which is great for preparing to run at high altitudes.

Vigorous Exercise

This target heart rate zone is 70–85% of your maximum heart rate. You breathe harder exercising at this intensity and would struggle to hold a conversation. 

A 40-year-old would average 127–153 beats per minute during vigorous exercise.

2. Taking Iron (If Needed)

Red blood cell production depends on iron availability. So, if needed, you can take iron supplements. Request a blood test and consult a doctor before making any big changes. Also consider:

• Taking iron with vitamin C to boost absorption.

• Increasing dietary iron through leafy greens, legumes, and lean meats.

3. Prioritize Hydration

• Drink more water than usual. The humidity is lower at high altitude, and you lose water faster.

• Watch for signs of dehydration and altitude sickness (e.g., nausea, headaches).

4. Antioxidants

At high altitudes, there’s less oxygen. This can cause the body to produce more free radicals (unstable molecules that can damage your cells). This kind of stress on the body is called oxidative stress.

Taking antioxidants, like Vitamin E or a daily multivitamin, can help because they neutralize these free radicals and protect your cells. It’s a good idea to start taking antioxidants before you head to the mountains to help your body adjust more easily.

5. Acclimate Gradually

If travelling to a high altitude, when you reach your destination:

• Spend the first few days adjusting and keep effort levels easy.

• Accept that your pace will drop – it’s normal.

• Slowly increase altitude levels (if going higher) and distance.

6. Respect Recovery Time

• Increase your exercise-to-rest ratio.

• At altitude, use a 1:2 interval ratio (e.g., 3 min effort = 6 min rest).

• Get more rest and sleep. Especially as it can be harder to sleep at altitude, with disbanded sleep and frequent stirring common.

7. Practice Breathing Techniques

• Use breathing techniques (such as yogic breathing) to regain control during breathless moments.

• Slow, deep breaths can help reduce panic and restore rhythm.

How Long Should You Stay at Altitude?

• Minimum effective stay: 3–4 days (to see a spike in the hormone EPO, which contributes to red blood cell production)

• Adequate ‘short stay’: 7–10 days

• Maximum benefit: Up to 30 days

  • After 30 days, EPO levels have been shown to plateau

To keep seeing improvements after this point, alternate between altitude and sea level training or increase the level of altitude you are training at.

How to Simulate High Altitude Training at Sea Level

If relocating isn’t realistic, simulating altitude can help runners gain some of the same benefits and experiences as spending time high above sea level.

Altitude Tents and Chambers

This equipment creates a low-oxygen environment for sleeping, adjusting or training in. Altitude tents fit over a bed or part of a bed, while altitude chambers are larger ‘rooms’ that can accommodate multiple people or be used for training sessions.

Altitude Tents: reduced oxygen levels inside the ‘tent’ allow you to sleep in a low-oxygen environment and get used to the experience.

Altitude Chambers: ‘room-like’ structures that create a low-oxygen environment for sleeping in and offer more space than altitude tents, meaning athletes can train in them.

Do High Altitude Simulators Increase Red Blood Cells?

Yes, high-altitude simulators can increase red blood cell production, which is a key benefit of altitude training. The reduced oxygen levels in altitude tents and chambers trigger spikes in erythropoietin (EPO), a hormone that boosts red blood cell production.

Altitude Training Masks

Altitude masks limit airflow and restrict breathing, you’ll inhale less air, which means your body receives less oxygen. While this doesn’t create a true low-oxygen (hypoxic) environment like high altitudes do, it can simulate some of the effects. For example, you may become short of breath more quickly at a lower intensity of exercise.

FAQ: Altitude Training for Runners

• How long does it take to acclimate to altitude? Most athletes need 7–10 days to begin adapting. Full acclimation may take up to 3 weeks.

• Can I benefit from altitude training if I only stay for a few days? Yes. Even a 3- to 4-day stay can trigger the hormone EPO to spike, which is what contributes to greater red blood cell production.

• How do I know the altitude training worked? You can have a blood test assess how much oxygen-carrying hemoglobin is present in the blood, which is a bodily adaptation to altitude training. But returning from altitude and noticing improvements – such as a new PB – is a great indicator of success.

• Are altitude training masks effective? Altitude training masks simulate restricted airflow, not actual oxygen deprivation. They can build mental and respiratory strength, but they don’t fully replicate high altitude environments.

• How much water should I drink at altitude? It’s advised to drink an extra 1–1.5 liters of water daily at altitude, adding up to a total of 3–4 liters. Your body loses water faster due to increased breathing and the drier air at altitude. This is particularly important for runners to keep in mind.

• What if I get altitude sickness? Mild symptoms (headache, nausea) are common. Rest, hydrate, and descend if symptoms worsen.

• What to wear when altitude training? When altitude training, wearing layers helps runners adapt to changing temperatures and weather conditions. A moisture-wicking base layer will dry fast and help moderate your temperature, while a quality outer layer, like a windbreaker jacket, will fend off wind and rain. Other items you can take on and off (hats, gloves) are also great for taking on elevation.

Hitting New Highs

Altitude training is a powerful training technique. Whether preparing for a race or looking to take your endurance to the next level, the key is preparation, proper hydration, patience, and respecting your body’s limits. Where will your training take you?