Hyperoxic training

Hypoxic training has been around for quite a while. The idea is to train and/or live in the environment with lower concentration of oxygen. This leads to the body producing more red blood cells, the effect similar to EPO doping. So when you exerciser inhaling air with normal oxygen content the performance improves. There are two basic ways to produce hypoxic environment: go to areas at high altitude or spend time in hypoxic chamber.

Reading the latest edition of the Lore of Running I came across opposite idea, training in the environment enriched with oxygen. One of the first people to try this was Roger Bannister who in the 1950-s broke 4 minute mile barrier. He was a medical student and then a research fellow at the time and spent some time in the lab studying running performance. They did a lot of interval training on the treadmill while taking blood samples for lactate concentration. Most subjects were serious athletes and were able to push themselves to the limit.

Among various factors affecting performance the researches tested the effects of inhaled oxygen concentration. Interestingly, some runners said that with oxygen mask on they could just run forever. Interesting, because it re-kindles the debate about what makes you tired during exercise. I don't remember exactly, but I believe there are three main theories of sports fatigue. One is Metabolic (proper name is different): as you exercise more and more energy production happens anaerobically, and the accumulation of lactate and the resulting acidosis severely impair the ability of the muscle cell to contract. Second, Substrate Depletion theory. According to this view, muscle cells get depleted of energy substrates: creatin phosphate, ATP, glycogen, so that there is no fuel for the muscle cell to contract.

There are some observations that contradict both of the theories above. Particularly the Substrate Depletion one. According to that theory finishing Ironman Triatlon in Hawai - 7.5 km of swimming, 180 km of cycling followed by full marathon - is a biochemical impossibility: there is just not enough energy substrate to cover this kind of activity.

Hence the third theory, that of the Central Governor. According to it is the central nervous system that limits the volume and intensity of exercise so that serious damage to the heart is avoided. What triggers the feeling of exhaustion is not clear, though it looks like the body temperature plays a role here. In any case, this theory makes most sense to me. Flexibility is limited by the nervous system, so is 1RM in lifting, so it is reasonable to suggest the same happens with endurance activities.

If the Central Governor theory is correct then the whole purpose of training is to re-set your Governor, so that it allows you to perform at higher intensity. There are various ways to fool the Governor in strength training. Plyometrics, for example. By pre-stretching the muscle before the jump Golgi apparatus is activated, and the resulting contraction of the muscle is stronger.

It looks like training in oxygen enriched environment may have similar effect on the Governor for endurance. With more oxygen in blood the physiological demands on the cardiovascular system are lower, and the brain gets fooled into believing that current intensity level is actually lower that it is. The result - you can sustain higher intensity longer, and the training effect is superior.

There is not much literature on the subject and frankly, I am a bit lazy to do comprehensive search. There is one interesting link -
http://www.pponline.co.uk/encyc/0427.htm - that discusses a piece of research on hyperoxic training on cyclists. Not exactly randomized or controlled, it is nevertheless impressive. A group of cyclists were followed throughout their training until they plateaued. After that hyperoxic training was introduced for six weeks.

Hyperoxic training improved the athletes' performances considerably. Quote from the link: Their endurance while pedalling at 85 per cent of maximal workload (90-95 per cent of maximal heart rate) increased by 32 per cent, and heart rate during high-intensity cycling declined by around five beats per minute, a change which would make tough pedalling velocities feel easier. Since the athletes had plateaued just before the hyperoxic work began, it's likely that the high-oxygen training was responsible for these two major advances. Importantly, the athletes achieved their gains without having to spend more time training; they trained with the same frequency and duration which they had used before the six-week, hyperoxic-training period. The only change was the raising of interval intensity from 85 to 95 per cent of maximal, an increase made possible by the supplemental oxygen. End of quote. Read the whole thing, it is interesting.

The bottom line? This weekend I am on call. I am going to borrow an oxygen cylinder from the hospital and do some snatches with the oxygen mask on. That must look freaky! I will report the results.