As a fairly new diver and an overweight one, i just thought maybe i should say a few things.first being about -dont run out of air! I learned that and its stuck in my head. Every dive i have been on i start accending when ive reached 500 pounds. Just my rule. Period! I will say that i wish more would have been emphasized on buddy breathing and running out of air completly. More practice drills and actually having your air cut off. I did have an incident when i was in cozumel but it was due to regulator issues and then the other instructor that i went diving with having having a large camera on the same sude as his alternate air source side, so when i went to use it, i got freakin nothing! The air line was twisted and pinched from his camera. We started buddy breathing on his 2nd stage but i panicked and went for the surface. We were only 15 feet down by this time but my point is not enough is emphasized and practiced. I relive this everynight but i am not going to let it slow me down. Oh and by the way- it was a night dive. Im glad this happened to me early in my diving adventure as it makes me more aware now of mine and others equipment. "Dont put your crap in my emergency space". On the health issue, i am an overweight female with a bmi of 40, but i have no heath issues at all except for my weight. Im 41and scuba diving is making me get myslf into better shape. I have great air utilization but i want my lungs to be stronger and able to expand more and hold more air. I work on this and have started riding my bike as well as eating better. 3 days of 2 tank diving wears me out but i know that and therefore are working to make myself better and stronger to have a safer more enjoyable diving experiencs. Ill be happy to answer any questions yall have about my post.