Both healthy cells and cancer cells gain energy from glucose, but healthy cells require oxygen to combine with the glucose, while cancer cells break down glucose without oxygen, therefore obtaining only 1/15th of the energy per glucose molecule that a normal cell produces. (This explains why people who consume excessive quantities of sugar may be more at risk from cancer).

Cancer cells are anaerobic, meaning they no longer require oxygen to metabolise. The anaerobic breakdown of glucose by cancer cells forms large amounts of lactic acid. Some of this is converted back into glucose by the liver, which in doing so uses one fifth of the energy per glucose molecule that a normal cell can; but that still leaves three times more available energy for cancer cells. This is wasteful metabolism that becomes self-sustaining and dominant unless (a) the cancer’s energy supply is eliminated or (b) oxygen or energy levels to normal cells are significantly increased.

In essence, therefore, advocates of oxygen therapy claim that it is the lack of oxygen on a cellular level that is responsible for disease. The greater oxygen levels in our bodies, the more resistant we become to viruses and harmful bacteria. This is the principle upon which oxygen therapy is based.