High-altitude training is typically characterized by training performed at altitudes of at least 2,100m (6,900 ft) above sea level. Starting at this elevation, barometric pressure decreases as compared to sea-level conditions.
As a result, oxygen molecules in the air are further apart, reducing the quantity inhaled with each breath. This factor increases as altitude rises.
Less oxygen in the air translates into a decreased level in the bloodstream of persons not accustomed to living in a high-altitude environment. This explains why people arriving from sea level to altitude feel poorly and fatigue quickly, especially with intense physical aerobic efforts, for a minimum of one week.
Researchers at the University of California San Diego School of Medicine suggested that living at elevation for at least seven days forces the body to adapt to an oxygen-poor environment by building up the red blood cell count.
Once back at sea level, the cyclist should see an increase in performance thanks to a flood of oxygen into the bloodstream carried by an abundance of red blood cells.
In this article, we’ll take a deeper look into the various benefits of training at altitude to improve cycling performance.
Improved oxygen delivery to muscles
As a cyclist, you’ve probably heard of EPO (erythropoietin), but in the negative sense as part of past doping scandals in professional cycling. EPO is a hormone that encourages the creation of red blood cells in our bone marrow that carry oxygen to our bodies to the muscles and other internal organs.
EPO exists naturally in our bodies. It’s produced in the kidneys and in modest quantities by the liver.
Because less oxygen is present at higher altitudes, our bodies compensate for the deficiency by creating additional amounts of EPO to serve hypoxic (oxygen-starved) muscles. Excess amounts of EPO are simply eliminated in the urine.
EPO’s function alone explains why cyclists turn to its synthetic form (rh-EPO) to improve performance. The harder you work, the more oxygen your muscles need to keep going.
Oxygen-deficient muscles produce lactic acid, which causes them to fatigue. It’s a build-up of lactic acid that sends the message to our brain that it’s time to stop, an undesirable result during a race.
Enhanced aerobic capacity
Living and training at altitude do more than increase the body’s red blood cell count to improve oxygen delivery to working muscles. It also enhances your maximal oxygen intake (VO₂ max).
What is VO₂ max exactly?
VO₂ max is defined as the quantity of oxygen your body can absorb during intense exercise. It’s also referred to as maximal oxygen uptake.
As oxygen enters our lungs, it’s turned into energy in the form of adenosine triphosphate (ATP). It’s the ATP that fuels our cells and helps our bodies expel carbon dioxide (CO₂), which is a byproduct of respiration.
The greater the VO₂ max, the more oxygen cyclists can consume during high-intensity exercise, and the more ATP is produced. The greater the amount of ATP, the higher the muscle fuel stores. This translates into a body better adapted to aerobic endurance activities such as cycling up a long mountain pass at altitude during a Grand Tour.
Key takeaway : A cyclist’s VO₂ max is often used as a predictor of athletic performance and can be used as a marker to track aerobic gains.
Increased lactic acid tolerance
We discussed above that lactic acid is a byproduct of muscles working at an intense level in an oxygen-deprived environment.
Increased levels of lactic acid in the blood lead to fatigue and muscle weakness or that little voice inside that tells you to take it easy.
The first stage of lactic acid levels in the blood is known as hyperlactatemia. As the blood lactate volume increases, it’s defined as lactic acidosis (LA). The body can typically compensate with hyperlactatemia, but the increased levels of the LA stage severely impede intense physical efforts.
Data shows that training at altitude increases muscle tolerance to lactic acid. As a result, cyclists can perform at intense levels for longer before feeling the effects of lactic acid. Heart rate has also decreased, which points to an enhanced aerobic capacity.
Oxygen levels by altitude
The table below shows the effective oxygen levels by altitude. Most of the high mountain passes used in the Giro d’Italia, Tour de France, and Vuelta Espana sit between 5,000 to 9,000ft (1,524 to 2,744m) in elevation.
|Altitude (ft)||Altitude (m)||Effective Oxygen (%)||Example location|
|1,000||305||20.15%||Ouagadougou, Burkina Faso|
|2,000||610||19.43%||Col d’Èze, France|
|3,000||915||18.72%||Col de la Madone, France|
|4,000||1,220||18.04%||Salt Lake City, Utah|
|5,000||1,524||17.38%||Col du Télégraphe, France|
|6,000||1,829||16.74%||Alpe d’Huez, France|
|7,000||2,140||16.11%||Col du Tourmalet, France|
|8,000||2,440||15.51%||Col du Granon, France|
|9,000||2,744||14.92%||Col de l’Iseran, France|
|12,000||3,659||13.27%||La Paz, Bolivia|
|13,000||3,963||12.75%||Yabuk Camp, Sikkim, India|
|14,000||4,268||12.25%||Pikes Peak, Colorado|
|17,000||5,183||10.85%||Everest Base Camp|
|18,000||5,488||10.41%||Mount Elbrus, Russia|
|19,000||5,793||9.99%||Mount Kilimanjaro, Tanzania|
|20,000||6,098||9.58%||Laila Peak, Pakistan|
|22,000||6,707||8.80%||Mount Pandim, India|
|27,000||8,232||7.07%||Cho Oyu, Nepal|
|29,000||8,841||6.46%||Mount Everest, Nepal|
|30,000||9,146||6.18%||Airline cruising altitude|