Courir en altitude

Running at altitude

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Trail running is becoming increasingly popular and the number of mountain races is increasing. As a result, it is only natural that runners are interested in running at altitude.Having been a very important subject of study at the beginning of the 1960s in preparation for the Mexico Olympics (a city located at latitude of 2200 m), there are certain restrictions associated with the altitude that must be taken into consideration. However it can also be of benefit for training purposes. Let us get an overview of the subject…

 

The features of high altitudes

As altitude increases, atmospheric pressure decreases:it is halved at an altitude of 5000m and three times less when you are 8000m above sea level. This drop in atmospheric pressure (called hypobaria) is what causes the funny sensation you may feel in your ears when you go up in altitude.Oxygen becomes rarefied (known as hypoxia) simply because there is less air. The consequence of this is a drop in the quantity of oxygen that the body can absorb and carry in the blood (called hypoxaemia). At the top of the Mont Blanc, there is only half as much oxygen as at sea level and, for those attempting to climb Everest, this figure drops to 30%.

The temperature also drops at altitude:it decreases by about 1° every 150m. And this drop in temperature will be felt even more due to the wind chill factor.

You will therefore have to take all of these factors into consideration before taking part in a mountain run. Make sure that the layers of insulation and hydration are suited to the conditions you will encounter. To do this you will have to look at the weather forecast before any outing at altitude.

 

The benefits of altitude on the body

But what are the long-term consequences of all these altitude effects? The body will adapt to the main physical factor, which is the increasing lack of air, hence oxygen, that reduces the body's capacity to produce effort. Initially, therefore, the breathing rate and heart rate will increase: these are the only 2 factors that the body can adjust immediately in an attempt to respond to the demands put upon it. This is what is known as the accommodation phase.

At the same time, the body naturally secretes a hormone (erythropoietin) that stimulates the production of red blood cells, which are responsible for carrying the oxygen in the blood.1 week after the accommodation phase, the red blood cells are mature enough to fulfil their role, such that the breathing rate and heart rate can slow down again.this is where the acclimatisation phase begins.

Indeed, it is this increase in the number of red blood cells that is the objective of altitude training because its effect is lasting: on return to sea level, the red blood cells remain for several weeks allowing runners to stretch their limits in training and racing.

 

How do you manage the altitude when running?

As has just been mentioned, the altitude is not without consequence on the body and on performance. If you are going to the mountains for a race and you do not have much time (3 or 4-day weekend), try to get there 1 or 2 days before the event. This will give your body some time to adapt to the attitude and surely prevent some of the side effects (problems sleeping, headaches).

If you are going to the mountains for a longer period, with the aim of improving your level of performance (increasing your VO2max and your ability to recover by increasing the number of red blood cells among other things), you need to spend at least 3 weeks at attitude.Less than this time and the body does not have the time to make all the necessary adaptations.Within the context of a training regime, you will have to slow down the pace during the first days of training for a period of 5 to 9 days depending on experience and your level of physical fitness.This will prevent certain physical difficulties which would reduce the benefits of your training sessions. Before going back down to sea level, you should reduce the pace of your training over the last 2 days.

 

How can you use the benefits of altitude training when running after coming back down to sea level?

On returning from the mountains, there is a window of 24 to 72 hours that is sometimes very favourable to achieving excellent performance levels, depending on the athlete. Generally, this is followed by a period of one week where the body cannot perform quite as well and during which it is adapting to its new living conditions. After this period of about 10 days following the return to sea level, performance levels will peak for about two weeks thanks to the benefits of the altitude training. It is therefore advisable to plan your altitude training dates in order to take full advantage for your running performance.

 

Training in the mountains can be of use to all runners, regardless of their level of performance.You just need to adapt the time you spend in the mountains and the intensity of the training to your level of mountain training expertise and your physical ability.When done properly, altitude training will give you a massive boost!

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