Preconditioning is a concept whereby the body is exposed to a form of stress or stimulation that will give it some protection. A classic example is formed by vaccines. You can protect yourself from dangerous viruses by injecting weak viruses. Exposed the body will produce antibodies as defense.
Meaning for HBOT.
HBOT is mainly used as protection against the consequences of ischemia, leading to an acute lack of oxygen. Our cells constantly maintain a balance between oxygen free radicals and the defenses against them. Free oxygen radicals are vital but dangerous when they are in excess, that is why cells produce defenses to avoid their excess. Following an interruption of blood circulation, the cells lack both, oxygen and free oxygen radicals. As a consequence cells will stop producing defenses against free oxygen radicals (oxygen-derived free radical scavengers). When the circulation is restored, oxygen and and free oxygen radicals are flowing in cells which lack defense against the free oxygen radicals because building this defense takes some time. Excess free radicals aggravate the cellular damage created by ischemia. This is called reperfusion injury.
HBOT can paradoxically protect the body against these deleterious effects if applied before circulation is reopened. In fact, HBO significantly increases the number of free radicals in a few minutes and therefore stimulates the production of protective enzymes whose lifespan is 24 hours.
Where do these protection mechanisms take place?
Experimental animal studies show a protective effect in the following organs: liver ( 1 , 2 ), heart ( 3, 4, 5 ), brain ( 6 , 7 , 8 ), muscles ( 9 ), spinal cord ( 10 , 11 ), kidneys ( 12 , 13 ), lungs ( 13 ), skin ( 14 ).