Ale Santuz: Running at 4000 m: the hypoxic chamber (altitude training).

Have you ever thought about training at altitude? If you are a runner with passion for mountains, probably the answer is affirmative.
But what's altitude training?
Wikipedia says that "the basic concept of living or training at altitude is to cause the body to adapt to the lower oxygen content by producing more oxygen-carrying red blood cells and hemoglobin. This improves the athlete’s ability to perform work, because more oxygen is available to the working muscles".
Why is there less oxygen at high altitude?
At sea level the air contains around 20.9% oxygen. On the top of Mount Everest (8848 m), too. Why do we say, then, that there's less oxygen? The difference is all in the air pressure: at sea level there is a pressure over our heads equivalent to 10 m of water. At 8848 m this pressure is equivalent to around 3.5 m of water. The percentage of the oxygen is the same, but being the pressure lower, the molecules are less compressed and, thus, more distant from each other: there are few molecules of everything in the same volume. That's why the oxygen intake is lower, if the respiration rate is the same.
Does this kind of training really improve performance?
Apart from the cool thing of running at 4000 m even if your city is at sea level, the results of hypoxia (lack of oxygen) training are not clear. As Prof. Dr. Joachim Mester said in his speech titled "Altitude training: on myths and methods" (you can find the pdf here), the analysis of more than 100 international studies in the last 40 years show:

"practical experiences and also controlled studies indicate performance enhancement effects, other do not;
acute and chronic hypoxia induce well-known physiological effects in gas exchange, hematology etc.;
performance enhancement may occur; it is, however, in onset, magnitude and duration very individual;
re-adaptation to sea level is quite rapid, the duration of positive effects is scientifically unclear;
the effects of all options live high/train low – train high/live low are not sufficiently proven;
criteria for individual input (training load at altitude) are often insufficient: High-low responders, early-late responders."

One thing is for sure: training at altitude (simulated or not) is hard!
I tried two different conditions in three different session. The first day (06/01/2012), the chamber was simulating the 4000 m conditions: 12.2% oxygen (18.0 °C the temperature, 41.5 % the humidity). The workout consisted in:

Warm-Up (2.50 km @ 4'35"/km);
1x1000, 1x800, 2x400 @ 3'40"/km, 2'30" recovery @ 7'30"/km;
Cool-Down (1.0 km @ 4'15"/km, 1.0 km @ 4'35"/km, 1.0 km @ 5'00"/km).

And here you have the HR graph:

HR acquisition of the 4000 m training (06/01/2012).

The second (09/01/2012) and the third day (11/01/2012), the chamber was simulating the 2500 m conditions: 14.8% oxygen (18.5-17.0 °C the temperatures, 72.5-60.5 % the values of humidity). Both workouts consisted in:

WU (3.00 km @ 4'35"/km)
4x1000 @ 3'30"/km, 2'00" recovery @ 7'00"/km
CD (3.10 km @ 4'35"/km).

Unfortunately the acquisition of the first training is pretty bad, but the data are very clear in the second graph.

HR acquisition of the first 2500 m training (09/01/2012).

HR acquisition of the second 2500 m training (11/01/2012).

When the oxygen percentage goes under 14%, things are really difficult: the recovery time appears to be far useless (actually it isn't, but my body said the opposite), breathing is difficult and HR cannot increase (188 out of 195 bpm, that is my max threshold) or decrease (150 bpm the lowest value between the repetitions) too much. For values of oxygen around 15%, everything is much easier and you can carry on your workout without any particular problems, even if the paces are slower than normal (the recovery time starts to be useful!).
Obviously if you train at low oxygen percentage, you should being constantly monitored: the oxygen saturation in the blood shouldn't go under 80%, to stay distant from hypoxemia risk (the use of a pulse oximeter, a device that uses a red and an infrared light to measure indirectly the oxygen saturation of the blood, is the easiest way to stay monitored).

Blood's oxygen saturation monitoring right after the training session.

For the record, al the data have been acquired in the Himaxx Center for Altitude Training in Berlin (Germany). If you have any question don't hesitate to contact me! Keep on training!

Here you can find a list of my running-related posts. Now shut down the notebook and have a run!

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