As athletes try to improve their athletic performance, new techniques keep popping up on the fitness scene. One method that has been gaining more popularity recently is high altitude training.

This exercise strategy involves working out at locations considerably higher than sea level, where the concentration of oxygen is lower and breathing is harder.

But that’s just the tip of the iceberg!

There is a mountain of interesting information regarding the types, effects, benefits, and equipment surrounding high altitude training. So, keep reading to find out scientific-backed facts about high altitude training.

What Happens to the Body During High Altitude Training?

Our bodies respond to being at varying levels of altitude in different ways. When we talk about high altitude training, the general idea is that exercise is happening at an elevation of about 7,000 to 8,000 feet above sea level.

At such an elevation, there isn’t as much oxygen in the air as we’re normally used to at sea level.

As a result, some changes occur in the body to adapt to the new environment.

Immediate/Short-Term Changes After Going to a Higher Altitude

These changes are how the human body adapts to survive in a low-oxygen environment.

These changes are also known as the acclimatization process, which takes place as you adjust to living at a higher altitude.

Acclimatization: Lungs

In high altitudes, the blood enters a state known as “hypoxemia.” This means that the blood has less oxygen than normal.

The very first change the body experiences when training at a high altitude is the increased rate of ventilation. This means you take more breaths in one minute.

But why does the body need to breathe more at high elevations? Because there’s less oxygen in your lungs for every breath, your body tissues also get less oxygen with each breath. So, the body is forced to take more breaths per minute to make up for the lower oxygen levels.

This change in breath frequency lasts about 10 to 14 days after arriving at a high altitude, depending on how high above sea level you are.

Acclimatization: Heart

When you go to a high point for altitude training, changes involving the heart, blood vessels, and blood (called the cardiovascular system) take place.

As such, you’ll experience the following effects:

  • Higher heart rate
  • Higher blood pressure
  • Heart pumping more blood
  • Heart pumping with greater force

These changes can happen as early as four to eight hours after arriving at a high altitude. The purpose is to make up for the lower oxygen levels across the body.

Acclimatization: Blood Components

As part of the cardiovascular system, the blood itself goes through changes when you go to a high altitude environment. These acclimatization effects include the following:

  • Higher number of red blood cells (type of blood cells that transports oxygen)
  • Heavier red blood cells
  • More hemoglobin (component inside red blood cells that carries oxygen)
  • Less amount of liquid in the blood (lower volume)
  • More erythropoietin production (that’s the production of red blood cells)

These changes in blood components take place within the first two to three weeks after arriving at a high elevation.

The drop in blood volume is due to dehydration resulting from taking more breaths. Breathing evaporates liquids from inside the body. Drinking more water while at higher altitudes is very, very important.

Acclimatization: Kidneys

The renal system also jumps on the wagon and responds to all the changes mentioned above through the following effects:

  • Higher secretion of bicarbonate (a compound that balances the pH or acidity of the blood)
  • More frequent urination
  • Expelling more phosphate and calcium in the urine (less phosphate and calcium in the blood)
  • Less expelling of hydrogen ions in the urine, so the urine becomes more acidic (and the blood less acidic)

Acclimatization: Nerves and Psychology

When you go to a high point for altitude training, changes in the nerves and psychology will also happen such as:

  • The vessels in the brain become wider
  • Less production of chemicals in the brain
  • Decrease in mental abilities
  • Mood changes
  • Decrease in sensations and movement

Acclimatization: Exercise

Woman wearing an endurance mask while running

During exercise at a high altitude, the blood has low oxygen levels because the lungs get less oxygen from the surrounding air.

Additionally, during the first couple of weeks after arriving at a high elevation, the maximal oxygen consumption or VO2 max (the maximum amount of oxygen that a person can use during intense exercise) is lowered.

Long-Term Changes From Living at a High Altitude

The long-term effects of staying at a high altitude environment result from chronic (long-time) exposure to the low oxygen concentration in the air.

The short-term effects discussed above will develop into long-term changes as the body goes through advanced or full acclimatization.

In adults, long-term changes can be summarized as follows:

LungsIncreased blood pressure within lung blood vessels
Less breaths per minute
More blood volume in lung blood vessels
If you suffer from chronic pulmonary disease, it becomes more severe
Suffering from high altitude pulmonary edema (HAPE) repeatedly
HeartLow blood pressure (systolic and diastolic)
The size of the right half of the heart increases (muscle hypertrophy)
Low level of oxygen in the blood
More fats in the blood
If you suffer from congenital heart disease, it becomes more severe
Potential heart failure
BloodHigh concentration of red blood cells
High concentration of hemoglobin
The blood has a larger capacity to carry oxygen
KidneysSlight increase of albumin (a type of protein) in the urine
High level of uric acid in the blood (can cause gout)
Less blood flow in kidneys Increased size of the blood vessels in the kidney
The kidneys work harder to filtrate blood
Nerves and PsychologyLower sleep quality
Brain tissues have less oxygen
You’re more likely to suffer from mood disorders (with higher severity)
Decrease in mental abilities
Reduced movement skills
Less motion stability
ExerciseLong-term decrease in aerobic exercise capacity

What Are the Types of High Altitude Training?

There are three main approaches to high altitude training:

Live High, Train High

First up, we’re looking at the classic method of high altitude training, commonly known as “Live High, Train High”.

This is the original approach in which athletes spend about two to four weeks at a high elevation location where they live, train, and sleep.

The aim is to induce altitude acclimatization by keeping the athletes in a continuous state of hypoxia. As a result, athletes get more red blood cells, enabling them to endure more physical stress and develop gains in performance.

There’s a catch though; if the altitude is too high, the quality and intensity of training will go down. Ideally, the altitude for effective “Live High, Train High” ranges between 5,900 to 8,200 feet above sea level.

In a study published in 2013, the effects of the “Live High, Train High” approach were tested in a team of Australian Football players that was divided into two groups.

One group lived and trained at a high altitude for 19 days while the control group lived and trained at sea level for the same period. This duration was part of an 8-week training plan.

In this study, the researchers monitored the athletes’ running performance using a running time trial of 2000 meters. They measured the training duration, training load, and perceived exertion rate.

The results of this study offered three facts:

  • The training duration was greater in the altitude group.
  • The training load was greater in the altitude group.
  • The mean rate of perceived exertion was greater in the altitude group.

In the 2000-meter time trial, the altitude group was faster and performed better than the control group.

As such, this study demonstrates that the “Live High, Train High” type of altitude training can help improve the performance of an athlete.

Live High, Train Low

Next up, we’re looking at the “Live High, Train Low” approach to high altitude training, otherwise known as sleeping at altitude.

In this type of altitude training, the athlete lives and sleeps at a high altitude location but trains at a lower elevation.

The limitation of this technique was quickly revealed to be the amount of time required to travel so that the athlete can spend the appropriate time at both locations. There would have to be a very special location choice that can adequately cut down the needed travel time.

This obstacle led to the development of equipment that can simulate the environment of a high altitude location, including altitude tents, altitude masks, and altitude rooms.

Using such equipment, the athlete can exercise at a normal elevation and then enter the modified altitude tent or room to live and sleep.

Still, there’s a catch; the athlete has to spend enough hours in the “high altitude” location to achieve the benefits of this training method. The recommended amount of time that an athlete should spend in hypoxia is around 14 hours per day.

Live Low, Train High

Shortened to IHB, Intermittent Hypoxic Breathing Training is a technique of high altitude training that simulates the conditions at a certain elevation while physically being at sea level.

Also known as “Live Low, Train High”, the athlete following this approach breathes air with a very low concentration of oxygen while sitting in a stationary position. The altitude breathing is done in intervals with instances of sea-level breathing scattered in the series.

The general protocol of IHB consists of five minutes of breathing low-oxygen air, followed by five minutes of breathing air with normal oxygen concentration.

The problem with this type of high altitude training is that not enough research has been done to show its effects. That’s because the induced state of hypoxia is usually too short to induce any of the acclimatization changes linked to this type of exercise.

That said, there’s a study published in 2003 that supports the hypothesis that IHB helps improve performance in endurance sports. Another study published in 2013 supports the claim that daily acute IHB boosts the walking capacity of patients suffering from a spinal cord injury.

What Are the Benefits of High Altitude Training?

Since high altitude training is a relatively new training technique, research efforts are still ongoing to determine the extent of its benefits in the world of fitness.

That being so, there are multiple advantages that people can potentially reap from incorporating high altitude training into their fitness routine.

1. Your Muscles Get More Oxygen

To be able to exercise, you need your muscles to work. For your muscles to exert effort, they need oxygen from the blood.

Oxygen helps the cells that make up the tissues of your muscles burn carbohydrates and other compounds to generate energy and do activities.

As you keep working out, your heart and blood lose the ability to meet the increasing oxygen demands of your muscles. Eventually, the lack of oxygen results in fatigue.

When training at a high altitude location was compared to training at normal sea level, a 2016 study found that hypoxic/altitude training can be more effective as it can improve the blood’s capacity for oxygen delivery.

One of the reasons for this positive effect is the increase in the production of EPO (erythropoietin); a hormone responsible for producing red blood cells that carry oxygen across the body.

2. Your Capacity for Aerobic Exercise Increases

In the fitness world, athletes keep track of their maximal oxygen consumption.

That’s the maximum amount of oxygen that a person can use during intense exercise that remains unchanged despite increasing the exercise load.

Following a high altitude training program can help raise the limit of your maximal oxygen uptake. According to this 2020 study, adolescent runners who participated in eleven days of altitude training experienced improved VO2 max.

This effect was also shown in seven professional distance runners who experienced an increase in VO2 max after completing 28 days of altitude training.

3. Your Tolerance to Lactic Acid Increases

In addition to an enhanced oxygen flow and aerobic exercise capacity, high altitude training can also help increase your tolerance to lactic acid; a byproduct of energy production in muscles.

The build-up of lactic acid in muscles causes fatigue. Incorporating high altitude training into your workout routine can help your body endure the accumulation of lactic acid for a longer time.

This tolerance boost is observed in the same 2020 study where adolescent runners were found to experience improved running velocity and cardiorespiratory fitness at numerous blood lactate levels.

How to Train for High Altitude While at Sea Level

You can bring the mountain to sea, aka perform high altitude training while at sea level using special equipment that can mimic the hypoxia conditions of a real high altitude location. For example:

  • Altitude chambers: these are oxygen-controlled rooms available in a wide range of sizes and specifications.
  • Altitude masks: these are masks linked to low-oxygen air generators; used in IHB and can transform your exercise into high altitude training by simply putting them on.
  • Altitude tents: these are cover-like structures that enclose your bed and are connected to a low-oxygen air generator.
Woman wearing mask while running

Wrapping It Up

There you have it! A guide to fascinating and scientific-backed facts about high altitude training.

This relatively new training method can promote oxygen blood flow to muscles, enhance aerobic capacity, and increase lactic acid tolerance.

While it can improve your endurance sports performance, exposure to a high altitude can also cause acclimatization changes to your lungs, cardiovascular system, blood, kidneys, and even your nervous system!



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