What does the repetitive group indicator measure?

The repetitive group indicator is designed to measure the residual nitrogen levels in the body tissues after a series of dives. When divers ascend, nitrogen from the breathing gas is absorbed into the body tissues at varying rates depending on the depth and duration of the dive. After a dive, some nitrogen remains in the body as a result of these absorptions and influences subsequent dive planning, particularly for safety and avoiding decompression sickness.

Using a repetitive group indicator allows divers to track the nitrogen levels effectively, which is critical for adjusting their dive profiles in successive dives. This indicator helps divers understand how much nitrogen is still present in their tissues to avoid exceeding safe limits during a subsequent dive. This information is vital for managing dive surface intervals and planning deeper or longer dives in a multi-dive day scenario.

While the other options mentioned—total dive time, depth of the last dive, and surface interval time—are important components in understanding dive profiles, they do not directly relate to the specific function of the repetitive group indicator in addressing nitrogen levels in the body.