This is my first post. I took the PFI course from Kirk and Martin 2 years ago in Miami. Fantastic experience. I am 62 years old, but am having pretty good results with my training. I do a lot of swimming with limited breathing, like breathing every 9th stroke for 100 meters and lots of variations on this. In the summer I dive in our local lake and do both some dives to depth and also dives to 20 0r 30 feet with increasing breath holds. I usually start at 1 minute and increase by 15 secs until I get to 3 minutes, and then I work back down. My best static is 5:16. Anyone that has any experience with breath hold and aging lungs, I would love to hear from them.