Tissue half-time describes the time required for the amount of gas in a particular tissue to change by:

Tissue half-time refers to the time necessary for a specific tissue in the body to undergo a 50% change in the amount of dissolved gas, such as nitrogen or oxygen. This concept is crucial in understanding decompression and diving physiology, as different tissues absorb and release gases at varying rates.

In the context of diving, when a diver ascends and experiences a decrease in pressure, the dissolved gases in their tissues begin to be released back into the bloodstream and ultimately exhaled. The half-time metric allows divers and dive professionals to predict how long it takes for the concentration of gas in a given tissue to decrease by half.

Understanding tissue half-time helps in planning safe ascent rates and decompression stops to prevent conditions such as decompression sickness or "the bends," which can occur if dissolved gases come out of solution too rapidly and form bubbles in the body. Therefore, recognizing that the "half-time" specifically indicates a 50% change is essential for safe diving practices.