Altitude exposure and physical activity became a popular concept with the believe that exercising at such environment helps to increase performance. Let’s breakdown the benefits to use altitude for training, increase performance and the last but not least health.

1. Gas exchange efficiency

The true quiz of the whole question lies in the air we breath. The truth is that at altitude there is no less O2. Air distribution is almost the same in the atmosphere about  78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. What does really happen is that the barometric pressure decreases as we stand on higher ground. Despite having the same gas distribution barometric pressure decreases with altitude and so does oxygen (O2) partial pressure.
What our body reads and adapts to is that the gas exchange function is challenged because of decreased barometric pressure and decreased O2 partial pressure.

Chart. PpO2 percentage decrease by altitude

All the physiologic processes and pathways inolved with gas exchange and its distribution that take place in the lungs. Those try to perform at its maximal capabilities using all posible resources but are unable to provide their complete function due to external factors.
This environment implies a cascade of physiological reactions and adaptations in order to maintain normal function and demands. These responses can induce specific adaptations that will allow to increase gas exchange dynamics and function overcoming the stress even under a challenging environment as is hypoxia.

2. Cardiac and ventilatory output

Turns out that this O2 deficit, detected by specific sensors on the circulatory system, implies a physiological challenge to wich respiratoy and cardiovascular systems reacts with different actue adaptations. Both, above all, will try to supply the demand (lack of O2 due to beforementioned gas exchange) induced by altitude and exacerbated by exercise.
Those acute effects will involve increased ventilation and breathing rate, increased heart rate and therefore increased blood flow. The reaction is simple, the system tries to provide supply faster, something that will work under normoxic enivoments and normal conditions, although gas exchange is not at its full potential. Long story short, increased cardiac load without increased efficiency. This scenarios applies indistincly to altitude exposure or exercising under such environment, until certain physiological adaptations are met.

3. Intensity thresholds

Due to altitude gas exchange environment conditions and our physiological acute adaptations to altitude a metabolic energy shift will take place.
Hypoxic environments will involve a metabolic shift and increaseing systemic intensity to a relative load compared to normoxia. Upon such environment intensity thresholds will move down in our metabolic profiles allowing us to push and stimulate certain higher pathways and biological process in a more accessible way allowing to push our bodies to maximized stress.
As higher you go and with more intensity you exercise closer you get to your physiological limits, intrinescally this translates to maximal aerobic potential and dynamism but higer grade of anaerobic participation as soon as aerobic pathways can not provide maximal efficency which they will not.

4. Altitude adaptations

Altitude offers a wide range of adaptations based on exposure and well to exercise at this environements:
+ It improves aerobic metabolism by enhancing energy efficiency and dynamism.
+ It improves the cardiovascular system mechanics.
+ It improves blood profiles.
+ It improves anaerobic metabolism.
+ It improves hormonal response and sensivity.
+ It improves function and physiologic performance.

5. Progression

Altitude is a resoursful tool to develop adaptations and biological profiles for athletic or health goals alike.
Altitude exposure can be natural or artificial. Artificial altitude or hypoxia is through hypobaric chambers, expensive and complex equipment. Altitude training devices that change air distribution simulating hypoxic environments reducing the overall percentage of O2 do not change gas partial pressure. Therefore altitude simulation per se its not the same althoguh some advantages can be driven from their use.

Different strategies to benefit from altitude are used (Train low-live high, Train high – live low,…) however the most important principle towards altiude adaptation is acclimatization wich involves temporary exposure to altitude and return to the previous altitude point within a time window matching hormonal and biological timings and behaviors.

About the author:
Albert Piñol – MSc in Physical Activity and Sports Science, MSc in Exercise Physiology, MAT Certified, DHE Snowboard Coach, DE Mountain Guide and Mountain Bike Coach. Specialized in exercise physiology, hypoxia, neuromuscular system and motor skill development. IG: @albert_pinol