When using a commercial dive operator for your recreational diving under most circumstances the dive op with require each diver to sign a medical release form. It’s a fairly standardized form and is used to scan for divers that may not be physically fit to dive.
I’ve been dealing with these forms since my OW certification. I do answer the questions honestly and this requires a doctor’s sign off statement for me to dive. I take a copy of the standardized form with me each year for my annual physical and have my doctor sign off on my diving. For any dive OP that may require it I keep a copy with my gear. So in effect unless all your dives are private ventures with your buddies then you should be required to have a physical withing 1 year of a dive.
I’m 48 and have been diving 4 years. I am now a DM and am headed towards Instructor in the near future. I’m actually in better physical shape now than when I became a DM but far from being an athlete. Yes, Diving is a physical sport but it is also one of skills and risk management. It is more important to properly judge your own limits and make decisions based on them. If you are taking on a dive that may be close to your limits be conservative and communicate the risks with your divebuddys.