Question:
I know that oxygen intake is good for the body, and I just wasn`t sure how to answer this question. Does the pressurized oxygen breathed in the hyperbaric chamber increase the production of free radicals in the body? A friend said that we take antioxidants to ward off the harmful effects of oxygen. Or, are free radicals even a concern when one is in the hypebaric chamber?

Answer:
We metabolize oxygen largely to produce energy so that our cells may operate. Simply put, in the absence of cellular energy, you are dead. In addition to making oxygen available to the cells for the production of energy, the body also generates free radicals (i.e., highly reactive oxygen species such as the superoxide anion or hydrogen peroxide). An important function of radical oxygen is immune, with certain immune cells producing free radicals, which are toxic to foreign cells like bacteria. In other words, free radicals are good. On the downside, free radicals can also damage native cells in the body (e.g., those that make up the tissues like liver or muscle). In this case, free radicals are bad.

In the hyperbaric environment, both the good and bad aspects of oxygen may be amplified to an extent, just as you would expect. Increased availability of oxygen, as is seen in the hyperbaric environment, can aid in the destruction of certain bacteria, for example, but patients may also be at elevated risk of oxygen toxicity.

Oxygen toxicity comes in two basic forms, acute and chronic. Acutely, high concentrations of oxygen under pressure may attack the central nervous system, perhaps rendering patients vulnerable to seizures (among other things). With longer exposures to oxygen, one may find that the lungs and the lenses of the eyes may show structural and functional changes. In both acute and chronic forms of oxygen toxicity, it is thought that free radicals are to blame.

The basic point is that you need free radicals, but they can also cause you trouble, perhaps contributing to degenerative disease and aging. By taking antioxidants (e.g., vitamins C and E), the intention is to ward off the trouble. Similarly, in the hyperbaric environment, the intention is to maximize the beneficial effects of oxygen while minimizing the risks of oxygen toxicity. Fortunately, we are now quite good at delivering hyperbaric oxygen with maximal benefit and minimal harm. That is not to say, however, that breathing hyperbaric oxygen is entirely without risk.