4 Secrets to Running at High Altitude + 5 Mountain Myths Debunked

Ever try running at high altitude when you're not used to the elevation?
Eavesdrop on tourists at the top of Colorado's Pikes Peak at 14,000 feet above sea level, and you'll hear...

  • “It’s like breathing through a straw!”
  • “Wow. There’s no oxygen up here.” 

There’s something incredibly alluring about the vast and wild beauty of high altitude mountains—their harsh, stark, yet stunning summits.
For many runners, including those who live at sea level, high altitude adventures are a bucket list item.
So how do you train for running at high altitude for epic races like Pikes Peak Marathon & Ascent, Ultra Trail du Mont Blanc (UTMB), or Hardrock 100?
In this article you'll learn...

  • The different classes of high altitude
  • How running at high altitude affects the body
  • 4 training secrets to prepare for running at high altitude
  • The truth about 5 prolific mountain running myths
Aurelien Dunand-Pallaz descends from the Hardrock 100 high point in 2023 when he won with a time of 23:00:30.

For the road runners reading this...

  • There isn’t as much demand for road races at high altitude when compared to trails
  • But there are a few road races that take place at high altitude such as the Bolder Boulder 10K and Utah Valley Marathon

Regardless of your preferred running terrain, you’ve probably caught whispers of the benefits of altitude training.
But what is altitude training and how does it benefit runners?
Keep reading and find out!

🏔️But first, let's define the different classes of high altitude

  • 🏔️An elevation between 4900 ft (1500m) and 11,500 ft (3500m) is what we’ll refer to as “high altitude”. Leadville 100, UTMB, and parts of the Western States course fall into this category.
  • 🏔️“Very high altitude” lies between 11,500ft and 18,000 ft (3500m-5500m). Pikes Peak Marathon & Ascent and Hardrock 100 top out around 14,000 ft. 
  • 🏔️“Extreme altitude” exceeds 18,000 ft (above 5500m)
At the Hardrock 100 in Silverton, Colo., runners climb 33,197 feet. The average elevation is 11,186 feet above sea level. The low point is 7,680 feet (Ouray) and high point 14,048 feet (Handies Peak).

How does running at high altitude affect the body?

In general, when an athlete is at altitude, the body’s oxygen transport systems are working double time.
Here's what happens...

  • To compensate for lower oxygen availability, the production of erythropoietin, AKA EPO, (don’t worry–naturally produced EPO is legal in sport) ramps up. 
  • EPO is a hormone secreted by the kidneys that stimulates red blood cell production. 
  • More red blood cells means more oxygen transport–and as runners, we need plenty of that sweet oxygen! 
  • However, the body is smart and will not overproduce red blood cells, thus, EPO produced as a result of altitude exposure is finite. 

There are two phases of adaptation to altitude...

📈Phase 1: Immediate adaptations to altitude

About 24-72 hours after you arrive at altitude, the body tries to artificially boost red blood cell count through a process called haemoconcentration...

  • Red blood cells. Haemoconcentration essentially means that the ratio of red blood cells (hematocrit) to fluid increases, making the blood more viscous. 
  • Heart rate. With this temporary increase in hematocrit, and lower plasma volume, the heart has to work harder to compensate, resulting in an elevated heart rate at rest and during activity. 
  • Ventilation rate. Additionally, your ventilation rate and depth of breathing increase because of the decrease in blood oxygen. 
  • pH balance. With all of these changes occuring, your body’s pH actually shifts and EPO releases to stimulate red blood cell production. 
  • Kidneys. The kidneys also respond to the pH change with increased urination. 

Some common symptoms you might feel during immediate adaptation to altitude are:

  • Headache
  • Loss of appetite
  • Fatigue
  • Poor sleep
  • Increased heart rate
  • Increased ventilatory rate

📈Phase 2: Long-term adaptations to altitude

After 2-3 weeks at altitude, your body has produced shiny new, mature red blood cells. 

  • Hemoglobin increases and blood plasma volume finally catches up to hematocrit. 
  • Each of these adaptations result in the body’s enhanced ability to carry more oxygen–and in you feeling much, much better.  
  • These longer term adaptations are what the pros are chasing when they visit high altitude training camps in locations like Flagstaff, Boulder, Colorado Springs, or Mammoth Lakes. 

But for the rest of us mere mortals who can’t afford to spend weeks immersed in the sport at high altitude, how can we find success above 4900 ft?
Here are the FOUR secrets to running at high altitude...

💪Secret #1: Get as fit as you possibly can!

No, the first secret is not to buy an altitude tent…
Fitness is the number one predictor of success at altitude.

  • The more consistent you’ve been in your training, the more likely you’re to show up at your target event and excel even if you’re coming from somewhere as flat as a pancake. 

Having the right balance of volume and intensity for your goals isn’t the most exciting concept, but it can make or break your experience in the mountains.

  • This is because altitude places stress on your aerobic systems and ability to use oxygen. Training hard and recovering, even at sea level, does the same thing! 

If you’re wondering about how to create the best training plan for your goals and training availability, it could be a prime opportunity to hire a running coach that understands high altitude training and racing– especially if a high altitude event is your A-goal for the year.

📆Secret #2: Time your arrival strategically

There are two options if you are coming from around sea level and want to perform your best at altitude. 

  • Option 1: Race before your body knows it’s oxygen deprived
  • Option 2: Arrive with at least one week before you’re planning to race

For athletes who have families, work full-time, and have busy schedules, making high altitude races week-long vacations might not always be the most practical. 

  • Thankfully, the body has a bit of a delayed response to lower oxygen availability.
  • If you can race before your body starts its initial adaptation process (24-72 hours after initial altitude exposure), you can avoid most of the negative effects of altitude.

On the other hand, if you can arrive at the race location at least one week in advance, this allows you to get over the acclimatization hump and feel your best on the big day!  

Both of these strategies should come with the important disclaimer that runners will respond at different rates to altitude acclimatization.

  • Illness, inflammation, genetics, and iron status impact a runner’s response to altitude, too.
DJ Fox devours a donut after summiting Pikes Peak (14,115 ft above sea level) from Manitou Springs. The ascent climbs more than 6,000 feet over 13.3 miles with a starting elevation of 6,412 feet above sea level.

😋Secret #3: Sip frequently & nibble often

The combination of drier air, reduced thirst signaling and greater fluid loss via urine, and increased respiration at high elevations make for the perfect storm of dehydration. 

  • Dehydration by as little as 2% (referring to a 2% loss in body weight) can negatively impact endurance performance.
  • Keeping on top of fluids at high altitude is critical–even more so if you’ve taken a long distance flight to your destination. 

A 2018 study on Israeli Air Force aviators’ fluid balance found that:

  • On average, subjects lost 462 mL every hour during flight. 
  • Of course, as a passenger on a plane, you’re not suited up and performing metabolically demanding tasks.
  • But this study highlights the surprising amount of fluid loss that can happen during a flight as the result of dehumidified cabin air and the body’s slightly elevated respiration rate. 

At elevations higher than 4,900 feet, the body makes some interesting changes when it comes to prioritizing oxygen delivery. 

  • In order to meet the body’s demand for oxygen, your metabolism increases. 
  • Consequently, carbohydrate metabolism ramps up. 
  • This means that carbohydrate utilization during exercise is higher at altitude than it would be at sea level. 
  • Taking in enough fuel to meet demands is critical, but it’s not always as simple as just eating more.

Similar to running in heat, the body starts to shunt blood away from the digestive tract and into the working extremities.

  • This can slow gastric emptying and produce GI distress with large quantities of nutrition while exercising at high altitude.

So what’s a runner supposed to do?

The best course of action–particularly in longer races where food intake is crucial, runners can implement the sip, sip, nibble strategy. 

  • Taking in smaller quantities of hydration and nutrition with greater frequency can offset some of the challenges at high altitude. 

If you’re running an ultramarathon, it’s wise to test out an array of foods prior to your race.

  • Sometimes your go-to gel or chew won’t agree with you at higher elevations. 
  • Having back up nutrition you’ve practiced with in training is never a bad idea. 
The author ascends the final miles of Pikes Peak during an early summer training run. It is not uncommon for well-trained runners to run 15-20 minute miles at very high altitude.

🚶‍♂️Secret #4: Slow it down

Your race paces will feel more effortful at high altitude. 

  • Your body is working even harder to move you over the terrain because of the lower oxygen availability. 
  • Expect your paces to be slower than they would be at sea level. 

Try to adjust your expectations prior to the race and prepare yourself to race intelligently.

  • Starting out slower can help you gauge your body’s response to the altitude, and if all goes well, you can ramp up effort later into the race. 

If you plan to run at altitude for a long period of time during a camp, it can be beneficial to use a heart rate monitor as a proxy for intensity.

  • You might not even realize how hard your heart is working to keep up–even if you’re running your sea-level easy paces! 
  • It’s also advised that athletes refrain from doing long tempos or hard intervals during their first week or so at high altitude. 
  • Short bursts of speed like strides or sprints and easy running is the best way to ensure a smooth adaptation period. 

🏔️5 mountain myths about high-altitude running debunked

Now that you have the four secrets to running at high altitude, let’s discuss some of the common myths surrounding these hypoxic locales.

❌Myth 1:

There is less oxygen present in the atmosphere at high altitude.

Fact: The gasses at altitude remain the same as they are at sea level. There is the same amount of oxygen present at the top of Everest as there is in Miami, Florida. 

  • The difference in the two environments is the atmospheric pressure. 
  • The decrease in partial pressure of oxygen at high altitude makes it more difficult for oxygen to enter the lungs and circulatory system.
  • The human body relies on a partial pressure gradient for inhalation, exhalation, and gas exchange from lung alveoli to capillary beds.

❌Myth 2:

Altitude masks or airflow restriction devices are a great way to prepare for high altitude goals.

Fact: There is no quality evidence to show that airflow restriction devices (ARDs) promote the desired adaptations that will improve performance at high altitude. 

  • ARDs make breathing during activity feel tough, but they aren’t stimulating EPO release and red blood cell production. 

❌Myth 3:

If you’re coming from sea level to high altitude, you’re guaranteed to get altitude sickness.

Fact: Individuals respond differently to high altitude. Your:

  • Genetics
  • Fitness
  • Prior exposure to altitude
  • Iron status, and...
  • Rate of ascent play into your response.

If you’re planning to spend an appreciable amount of time (weeks/months) at high altitude, it’s not a bad idea to:

  • Get a comprehensive iron blood work panel 8-10 weeks prior to your trip. 
  • Your stored iron, AKA ferritin, should be high enough to meet the increased demand for iron in red blood cell production once you are at high altitude. 
The author runs up a steep incline at 12,000 feet above sea level.

❌Myth 4:

I’m going to commit to altitude training. I should go as high as possible for as long as possible to get the benefits.

Fact: More is not always better in the case of high altitude. 

  • Most of the positive benefits begin to diminish above 10,000 ft. 
  • The stress your body experiences during long periods of time spent training above 10k will likely compromise adaptation and training quality. 

The popular method of sleeping high and training low is designed to maximize the benefits while minimizing the negative effects of a hypoxic environment. 

  • Runners cannot train as hard at high altitude as they might at sea level, which results in slower paces during workouts and compromised intensity levels. 
  • By training at lower elevations and then returning to high altitude for sleep, athletes expose themselves to reduced oxygen during recovery, but they don’t sacrifice workout quality.

❌Myth 5:

I’m planning to race a high altitude event, therefore, I MUST go train at altitude or use an altitude tent beforehand.

Fact: Altitude training at a camp or with an altitude tent is a matter of marginal gains. 

  • Elites do it since they are already operating near the top end of their athletic ability and are attempting to squeeze out the last 1%.
  • Most sub-elite runners haven’t exhausted all of their training options to achieve peak performance. 
  • Quite often, athletes will benefit more from adding training volume and threshold work than they will from adding the stress of altitude.

It’s worth noting that runners who visit high altitude training camps are most likely benefiting more from the limited distractions and the sole focus on their training than they are from the altitude itself.
🔥If you’re interested in using heat training to prepare for a high altitude event, check out this article

📈Have you ever run a race at high altitude?

What mountainous adventures do you have on your bucket list? Let us know in the comments!

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Abigail Lock
Durango, CO
24 Following

Endurance athlete with a proclivity for mountain running and high altitude desert dwelling. NASM Certified Sports Nutriti...


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