@Jamesaaa, you did not mention your blood pressure? Have you already had a heart attack with resulting heart damage? Lung efficiency 100% or less?
I am choosing to add a lot of shallow snorkeling lately, in places where there there is loads of life in just a few feet of water, in both northeast and Bermuda. It is easier on the body to not lug the heavy tanks and weights etc. i suggest you find better, shallower, snorkel spots, like Northeast, places with less sand and more critters. Don’t scuba, here’s my reasoning:
the swimming for 45 min to an hour is a lot of strain, plus doing multiple dives usually two per boat trip. It doesn’t compare to the pool work you’ve described.
Then there is the increased pressure on the body at depth. Then there is the increased blood pressure from adrenaline.
The problem is not just that you’ll have heart attack and die, but that you might get other people killed as they try to lug you back to the boat, ruin there lives that they have to experience this kind of “Closed Casket” horror.
On the other hand, I’ve seen so many unhealthy looking types on boats, i think you wouldn’t be alone if you did go, but you MIGHT set off a chain reaction, first your have a small heart attack, your buddy tries to lug you and has a stroke, another diver sees this and panics shooting straight to surface, (while holding breath), knocking the regulator out of HIS buddies mouth, who panics and gloms onto the DM, who tries to save that guy but gets hit by dive ladder while struggling with the guy, and hit again when boat captain tries to pull them both out of the water but falls in himself, right on their necks. Leaving an empty boat, drifting silently on the calm seas.