Hyperbaric is simply referencing a condition that is above standard atmospheric pressure.  Instead of breathing the normal 21% oxygen, the therapy involves breathing 100% oxygen in a chamber that is moderately pressurized to 1½ to 2 times normal, for an hour or more per day.  Oxygen Therapy has been used around the world for over fifty years in the prevention and improvement of debilitating conditions and in the enhancement of overall health.  

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