Yeah I reached my plateau years ago now I'm in my "twilight" years of diving. I'm not as strong as I was I get winded easy because I can't run anymore MD orders after getting 2 replacement knees...
@AfterDark,
Have you thought about swimming laps and doing NordicTrack or elliptical as an alternative to running, for cardiovascular fitness?
What is your "Plateau?"
@Boston Breakwater,
My first open water class was in 1986, when I was 31 years old. Within a couple of years I had earned cavern and basic cave certifications, and a few years after that I was doing "Advanced Deep Air", "Extended Range", and "Technical Nitrox" dry suit, decompression dives on Great Lakes Shipwrecks. Shortly after I began my family in the early 2000's, I ceased doing this type of advanced diving.
I now really enjoy doing relatively shallow (< 60 fsw) recreational dives in MO and AR Army Corps of Engineers lakes, using simple, basic, minimalist gear (sometimes using a VDH-upgraded 1959-era double hose regulator, I purchased a couple of years ago). I never have relied on a DC, and I ceased using a BC a couple of years ago. I suppose I will have reached my personal diving plateau, finally, when I begin using a J-valve and pull rod! (I'm hoping to purchase these soon.)
My diving currently is on hiatus as I wait for some replacement "suspension parts." My planned surgeries have been rescheduled a couple of times because of the COVID-19 public health emergency. But, I expect to be back in the water by the end of summer!
rx7diver
P.S. Eventually I hope to purchase a digital camera body and U/W housing, and dust off and resume using my 15mm U/W Nikonos lens during these minimalist dives.