What does the high gradient factor (GF High) indicate?

The high gradient factor (GF High) is an important aspect of decompression theory in diving, specifically relating to how divers manage their ascent to avoid decompression sickness. GF High is a parameter used in decompression models that indicates the maximum pressure gradient allowed between the tissue compartments of a diver's body and the surrounding water as they ascend.

When you dive, nitrogen is absorbed into your body tissues under pressure. Upon ascent, if the ascent rate is too quick, dissolved nitrogen in the tissues may form bubbles, leading to decompression sickness. The GF High specifically dictates how aggressively you can perform your ascent relative to the nitrogen saturation level in your tissues. A higher GF High means that there is a larger allowable gradient before you start to reach safe surface pressures, indicating a stricter limitation on how quickly you can ascend without risk.

While discussing residual nitrogen at the surface, it's crucial to understand that GF High helps in managing this aspect by dictating the ascent profile that minimizes nitrogen remaining in the body, thus reducing the risk of decompression sickness upon surfacing. Other options, such as the pressure at depth, ascent speed percentage, or water temperature, do not provide insight into the implications of nitrogen saturation and its management during ascent, making them less relevant to the