High-altitude running involves training or competing in locations situated at elevations of 5,000 feet or higher. Oxygen levels decrease as elevation increases, presenting a demanding environment for athletes.
Over recent years, many endurance athletes have increasingly turned to high-altitude areas in pursuit of performance advantages.
Running in thinner air challenges the body in new ways, encouraging physical adaptations that may enhance competitive edge.
Athletes are drawn to these environments for the physiological changes that come with adaptation. They believe training under these conditions can help maximize their capabilities when returning to lower altitudes.
How High Altitude Affects the Body
At high altitudes, oxygen availability drops significantly. Less oxygen in the atmosphere means less is delivered to the muscles during physical exertion.
Bodies must work harder to maintain the same intensity, making even routine workouts feel more strenuous.
Cardiovascular strain intensifies. Heart rate increases to compensate for the diminished oxygen supply, and breathing becomes more rapid.
Muscles fatigue faster, and athletes often struggle to maintain their usual training volume or intensity.
The struggle isn’t a setback, it’s the first step toward adaptation. Lower oxygen levels push the body into a state of constant demand, which leads to beneficial changes if managed with care.
But it’s important to recognize that performance may dip temporarily as the body adjusts.
Adaptations and Benefits
Running at high altitudes places extraordinary demands on the human body.
Over time, these demands prompt a series of physiological adaptations aimed at improving performance, endurance, and oxygen efficiency.
Athletes who spend consistent time training at elevation often notice significant improvements once they return to lower levels.
Increased Red Blood Cell Production

Exposure to reduced oxygen levels stimulates the kidneys to release erythropoietin (EPO), a hormone that prompts the bone marrow to generate more red blood cells.
These cells serve as carriers for oxygen, moving it from the lungs into the bloodstream and eventually into muscles during physical exertion.
Benefits include:
With more red blood cells in circulation, athletes can perform at higher intensities for longer durations.
Enhanced VO2 Max
VO2 max reflects the maximum volume of oxygen the body can utilize during intense physical activity. Training in hypoxic environments challenges the respiratory and cardiovascular systems to adapt, eventually raising this metric.
Advantages of an increased VO2 max:
Athletes with higher VO2 max levels often dominate endurance events, as their bodies require less effort to deliver needed oxygen.
Improved Aerobic Efficiency
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With regular altitude exposure, muscle cells learn to use oxygen more effectively.
Mitochondrial density increases, and muscles shift toward burning fuel more efficiently, delaying the switch to anaerobic energy systems.
Key outcomes:
Muscles become less prone to early fatigue, which benefits distance runners, cyclists, and triathletes.
Increased Capillary Density
Sustained hypoxic stress promotes the growth of new capillaries in muscle tissues.
These tiny blood vessels enhance the transfer of oxygen and nutrients between the blood and muscle fibers.
What this leads to:
Improved capillary density supports high-volume, low-intensity training and aids in muscle recovery.
Greater Lactic Acid Tolerance
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*This article was originally published in the Dec/Jan ’23 issue of UltraRunning Magazine.https://t.co/hzWA8JtIKI— UltraRunning Magazine (@UltraRunningMag) February 23, 2024
Repeated workouts in low-oxygen environments teach the body to handle rising levels of lactic acid without breaking down as quickly.
Increased buffering capacity means athletes can push past thresholds that would normally force them to slow down.
Performance enhancements include:
Athletes conditioned to tolerate lactic acid often surge when others fade, especially in races with hilly terrain or sprint finishes.
Hydration and Nutrition at Altitude
Dry mountain air and increased breathing rates accelerate fluid loss. At elevation, the body also produces more urine, compounding the dehydration risk. Staying hydrated becomes essential to sustain performance and avoid altitude sickness symptoms.
Electrolyte replacement, especially sodium, is critical. Sweating rates may remain the same or increase, but fluid retention declines. Consuming sports drinks, salt tablets, or natural electrolyte sources helps maintain balance and prevent cramping or dizziness.
For athletes seeking respiratory support at high elevation, portable oxygen options like revo2.com can provide a quick oxygen boost to improve recovery and reduce symptoms of altitude fatigue.
Iron plays a crucial role. Red blood cell production demands adequate iron stores, and a deficiency can blunt altitude adaptation. Iron-rich foods like red meat, beans, lentils, and fortified cereals should be emphasized in the diet.
Careful planning around meals and fluids can make or break an altitude training block. Timing, portion sizes, and nutrient density must all support the body’s increased physiological stress in these environments.
Training Methods

High-altitude adaptation strategies differ depending on an athlete’s goals, location, and available resources.
While some choose to immerse themselves fully in altitude environments, others balance altitude exposure with performance-oriented training sessions at sea level.
Choosing the right one requires careful consideration of race conditions, recovery capacity, and access to altitude facilities or natural high-elevation locations.
Live High, Train Low (LHTL)
Living at altitude while conducting high-intensity workouts at lower elevations allows the body to adapt to lower oxygen levels while still preserving workout quality. This method has become a preferred approach for elite athletes due to its dual effect on performance and adaptation.
Sleep and recovery take place in a hypoxic environment, encouraging physiological responses such as erythropoietin release and increased red blood cell count.
Meanwhile, workouts are performed where oxygen is more abundant, supporting high training intensity.
Key advantages include:
Successful implementation often involves athletes living at elevations between 6,000 and 8,500 feet while commuting to lower altitudes for key workouts. Many elite training centers in Colorado and Utah support this method with structured logistics and altitude houses.
Train High, Compete High

Preparing at elevation for events that will also take place at altitude allows the body to get accustomed to race conditions.
Muscles, lungs, and the cardiovascular system adapt to the reduced oxygen levels, improving performance efficiency under similar stress.
Best suited for:
Benefits include reduced altitude sickness risk on race day, better pacing strategies in low-oxygen environments, and more controlled breathing patterns.
However, care must be taken to manage fatigue, as training intensity typically decreases with prolonged high-altitude exposure.
Train High, Compete Low
Training at high elevation and then racing at sea level takes advantage of physiological improvements gained in low-oxygen conditions.
Once athletes return to oxygen-rich environments, endurance performance often improves significantly.
Muscles receive more oxygen per heartbeat, and fatigue onset is delayed due to better oxygen delivery and lactic acid tolerance.
Ideal for:
Performance improvements typically include:
One challenge with this method lies in timing. The positive effects of altitude exposure often peak within 7–20 days after returning to sea level, requiring precise scheduling before competition.
Summary
@thefashionjogger WELCOME TO ST. MORITZ ❤️🇨🇭Ready for the high altitude training in one of my favorite places 😍 Day 41/84 MARATHON TRAINING 💪 #running #runner #sport #fyp #marathon #workout #cardio ♬ Bye Bye Bye – *NSYNC
High-altitude running offers measurable advantages for athletes willing to embrace the challenge. Improved oxygen efficiency, enhanced stamina, and increased red blood cell production are among the key rewards.
Training at elevation works best for athletes with structured plans, clear goals, and enough patience to allow proper adaptation.
Careful scheduling, dietary support, and recovery strategies ensure the body can perform at its best both during and after altitude exposure.
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