Oxygen is life, without it we can't exist
Our body requires 96% - 100% of Saturated Oxygen (Red blood cells carrying capacity), and that Oxygen needs to be replaced constantly everyday just to perform the functions of daily activity. If our oxygen saturation falls below 85%, this will cause Hypoxia.  

Some hypoxia symptoms include:

• Restlessness.

• Headache.

• Confusion.

• Anxiety.

• Rapid heart rate (tachycardia).

• Rapid breathing (tachypnea).

• Difficulty breathing or shortness of breath (dyspnea).
   

We have no system to store oxygen like we do for fats. The air we breath contains 21% Oxygen at sea level and is even lower the higher you go. If you go below sea level a gradient is created and the way we absorb oxygen completely changes. When the pressure in the chamber increases it mean that the pressure outside of the body is greater than the pressure inside the body. This is how oxygen absorption is increased.

Boyles law & Henry's law explain how this increase is achieved. We can dissolve more oxygen into our blood plasma and into our body's tissue when these laws are applied to a hyperbaric oxygen chamber.