In IANTD air diving, what is the purpose of surface intervals?

The purpose of surface intervals in diving is multifaceted, but a key aspect is to allow the body to eliminate excess nitrogen it has absorbed during the dive. When divers use compressed air, the nitrogen from this air dissolves into the body at higher pressures. As the diver ascends and the pressure decreases, the body needs time to safely off-gas this nitrogen to prevent decompression sickness. Surface intervals are essential for this process, providing a necessary pause before the next dive to help ensure the diver's safety and well-being.

While it is true that surface intervals can also contribute to physical recovery and assist with decompression, these aspects are secondary to the primary purpose of reducing nitrogen levels in the body. Therefore, the main aim of adhering to appropriate surface intervals is to manage nitrogen off-gassing effectively.