Why was the compression to breath ratio changed?

The compression-to-breath ratio (CBR) in scuba diving regulators was changed to improve diver safety and comfort. The original regulators used a high CBR, which meant that the diver had to breathe against a greater resistance. This could lead to fatigue and increased respiratory effort, especially during deep dives or when using a high-pressure gas supply.

The reduced CBR in modern regulators makes breathing more comfortable and reduces the risk of fatigue and other breathing-related problems. This is particularly important for divers who are new to the sport or who have respiratory conditions. The lower CBR also allows divers to breathe more naturally and efficiently, which can improve their overall dive experience.

In addition, the reduced CBR helps to prevent free-flowing regulators, which can occur when the diver's breathing rate exceeds the regulator's ability to supply gas. This can lead to a loss of air and a potentially dangerous situation. By reducing the CBR, the risk of free-flowing regulators is minimized, making diving safer.

Overall, the change in compression-to-breath ratio in scuba diving regulators was made to improve diver safety, comfort, and efficiency.