ATA stands for ‘atmospheres absolute’, and is a term used to measure the pressure of the air surrounding us at any given time.
When an individual is at sea level, the air is at 1.0 atmosphere absolute - about 14.7 pounds of pressure per square inch. While in a HBOT chamber, the ATA is increased multiple levels, allowing rapid oxygen absorption into the bloodstream and increased distribution of oxygen to all areas of the body.
The rate of oxygen absorption doubles with every increase in atmosphere absolute, but this doesn’t necessarily mean that higher is better.
At 2.0 ATA, the oxygen saturates any remaining oxygen-deficiency in the hemoglobin, and is then sent to nourish plasma all around the body. Every ATA increase from that point on exponentially increases the amount of oxygen forced into the bloodstream, but must be monitored and permitted for a finite period.
Oxygen toxicity, which occurs when an excess amount of oxygen becomes trapped in the body’s tissues due to overexposure or inappropriate ATA, can result in damage to the central nervous system and go so far as to induce seizures.
Mild Hyperbaric Oxygen Therapy chambers (mHBOT for short) can be pressurized between 1.3 - 1.7 ATA, while hospital-grade multi-place chambers go as high as 6.0 ATA.