Nikki, I think all divers should be reasonably fit--both cardio and strength. Overall fitness helps will help your SAC rate, decompression, and comfort. There is a good book…Fitness for Divers by Cameron Martz—it’s a great resource. http://www.divefitness.com/ As for rescue diver it’s not a very strenuous course or labor intensive course. When I took my course we pulled the distressed diver out of the water as a team. In the real world you will most likely have help from the boat crew or shore support getting an unconscious diver to safety. Plus, don’t hesitate to grab a knife and cut the gear off—it can be replaced a life cannot. Good luck. Vinny