Even moderate altitudes can have a significant effect on athletic performance. Click to see the effects on physical performance at altitude.
All athletes seek a competitive advantage. Although the benefits of some interventions (like training, for example) are clear, most strategies are less well proven. Altitude is no exception to this. Training at high altitude has been used by competitive athletes as a means of improving their potential. However, despite a good deal of research into the topic, its true effects and a recommended approach are still not well established. Additionally, altitude training is usually expensive and fraught with logistical problems.
Exposure to high altitude could theoretically improve an athlete’s capacity to exercise. Exposing the body to high altitude causes it to acclimatise to the lower level of oxygen available in the atmosphere. Many of the changes that occur with acclimatisation improve the delivery of oxygen to the muscles -the theory being that more oxygen will lead to better performance.
For any type of exercise lasting longer than a few minutes, the body must use oxygen to generate energy. Without it, muscles simply seize up and can become damaged. This type of exercise is called aerobic exercise, meaning with oxygen.
The body naturally produces a hormone called erythropoetin (EPO) which stimulates the production of red blood cells which carry oxygen to the muscles. Up to a point, the more blood cells you have, the more oxygen you can deliver to your muscles. There are also a number of other changes that happen during acclimatisation which may help athletic performance, including an increase in the number of small blood vessels, an increase in buffering capacity (ability to manage the build up of waste acid) and changes in the microscopic structure and function of the muscles themselves.
However, acclimatisation to high altitude is not simple, and there are a number of other effects that could cancel out the above benefits. For example the increase in red blood cells comes at a cost - having too many blood cells makes the blood thicker and can make blood flow sluggish. This makes it harder for your heart to pump round the body, and can actually decrease the amount of oxygen getting to where it is needed.
At very high altitudes (>5000m), weight loss is unavoidable because your body actually consumes your muscles in order to provide energy. There is even a risk that the body’s immune system will become weakened, leading to an increased risk of infections, and there may be adverse changes in the chemical make-up of the muscles. Additionally, the body cannot exercise as intensely at altitude. This results in reduced training intensity, which can reduce performance in some sports. At very high altitudes, further problems are encountered: loss of appetite, inhibition of muscle repair processes and excessive work of breathing. On top of this, there is the problem of altitude illnesses, which can dramatically reduce the capacity to be active at altitude, or foreshorten the exposure to high altitude altogether.
Taking some of the information about altitude training into consideration, various techniques have been devised in order to expose the athlete to the beneficial effects of high altitude whilst not reducing their ability to train effectively. These have been labelled ‘Live High – Train High, ‘Live Low – Train High’ and ‘Live High – Train Low’. The typical altitudes used are around 2000-2500m, which in itself reduces the risk of some of the unhelpful effects of altitude exposure. The ‘low’ altitudes may not actually be at sea level, but could be 1250m, for example. However, the difference between the two altitudes is significant enough to have an effect on training [see the difference in oxygen and pressure at these altitudes with our high altitude calculator].
Maximum exposure to altitude. Evidence of a positive effect at sea level is controversial, and there is less support for this method amongst experts.
The idea behind this regime is that the athlete is exercising in a low oxygen environment, whilst resting in a normal oxygen environment. There have been some interesting findings suggesting that this technique might work, but there are no good studies showing that the technique makes any difference to the ultimate competitive performance of the athlete at sea-level. Additionally, training intensity is reduced so some athletes may find that they actually lose fitness using this regime.
The theory behind this regime is that the body will acclimatise to altitude by living there, whilst training intensity can be maintained by training at (or near) sea level. Hence, the beneficial effects of altitude exposure are harnessed whilst some of the negative ones are avoided. However, residence at altitude must be for more than 12 hours per day and for at least 3 weeks. With this technique, improvements in sea-level performance have been shown in events lasting between 8 and 20 minutes. And interestingly, athletes of all abilities are thought to benefit.