Cycling
< Previous Article
Effect of Hypoxic Interval Training on Cycling Performance
Written by Dr. SkibaI was at the university gym a couple of weeks back, and heard two members of the track team discussing altitude training. They were considering traveling to high altitude before a major competition, because they had heard that training at altitude would benefit their performances. One of them also suggested that it was possible to "get a tent like Lance has" to do the same thing year round. We got to talking, and I very quickly realized that there are a lot of misconceptions out there regarding altitude and what it is supposed to do for you. In this article, we will discuss a little about some of the current research involving high-altitude training.
Altitude training has been thought to increase athletic performance by increasing the number of circulating red blood cells. This occurs because of a decrease in the amount of oxygen present at high elevation. In other words, your body senses the decrease in oxygen, and chooses to make more red blood cells to try and carry more of what little oxygen is around. As the fellows above commented, companies have been founded to manufacture tents which simulate high elevations by artificially decreasing the amount of oxygen present in the tent. In general, however, serious athletes have traditionally either lived at altitude, or participated in camps of several weeks duration to attempt to gain the benefits of decreased oxygen concentration. There are problems with this strategy. For example, if the athlete goes high enough that the body is stimulated to produce more oxygen carrying red blood cells, he or she is generally too high to successfully complete intense workouts. There just isn't enough oxygen around to support a very high workload for a sufficient period of time. It is sort of a catch-22: the body will only produce more blood cells when it senses a decrease in oxygen, but the reason it is making the cells is because the body is not operating optimally due to the decrease, and there isn't much point training if you aren't able to train well. Also, high altitude results in a loss of muscle mass...not good for an athlete who has gone through a lot of trouble to build it.
Hence, people came up with the idea of intermittent hypoxic training. The idea is that the person exercises in a decreased oxygen environment for short periods, but does not remain there long enough to suffer the effects of muscle cell deterioration or detraining. The results from this technique were mixed. So, a guy named Candau and his group decided to try something different. They asked, “What if we make the athlete do the intervals at a normal oxygen concentration, so that they can do a very hard work period, and then make the athlete do the recovery intervals at a decreased oxygen concentration, to stimulate the body to make more blood cells?”
The investigators rounded up 30+ cyclists and triathletes, and split them into three groups. One group did two interval sessions a week in normal conditions (Nor). The second group did the same workouts under a decreased oxygen concentration (IHT). The third group did the experimental workout (IHIT). The results were interesting: After 4 weeks, all groups improved by about 5% in a 10 minute TT between the groups. Also, there was no further improvement seen after 3 more weeks of training. VO2max did improve in the IHIT group, however, this did not translate into a performance improvement. Finally, there were no differences seen in blood tests between the groups.
The investigators were forced to conclude that their technique, while nice in theory, did not seem to pan out in practice. Moreover, since performance did not continue to improve after the third week of interval training, it would seem that periods of intense training do not need to continue very long before the stimulus ought to be changed. Finally, these results should make athletes consider whether altitude training is really worth the expense of a tent, or of travel, given that no performance difference was seen in any of the treatments.
Reference:
Roels et al. Effects of hypoxic interval training on cycling performance. Med. Sci. Sports Exerc. 37(1): 138-146. 2005.
