Recently, a very active SOTA activator who had probably 80 or 90 summits to his credit suffered a heart attack while on a climb. These events are always a little sobering because we aren't so different in age. It isn't intuitive that an active individual would be a heart attack candidate. The fact is he had 100% blockage in one of his arteries. My son is an MD and explained that the body will build it's own bypass system over time, so 100% blockage means that the main artery was blocked, but there were several smaller bypass blood vessels that were at least transporting some blood, but obviously in the case, not enough.
There were two lessons to learn from this incident. The first in the preventive part. After say, age 50, we should have a full blown physical at least every other year, complete with an EKG that will check you heart capacity and function. If you have to borrow money to pay for the physical, you should do it. A physical is not an expense, but an investment that will yield a nice return in the form of additional years to enjoy all the things you have worked for in your life. We should do some exercise at least 4 times a week, even if it's just walking for 30 minutes. If you aren't currently exercising, get the physical first and if you are exercising don't assume that you don't have issues. The example above should be enough evidence to convince you of that. One health issue associated with ham radio is that we can do it sitting down which isn't necessarily good from a health perspective.
The second lesson from this is the pound of cure. If you are involved in outdoor activities, hiking, biking, etc.. carry a small first aid kit and include aspirin in the kit. This will help to temporarily mitagate heart attack symptoms until help can arrive. Get a book on outdoor first aid and understand what you can do when you are miles away from help and have a medical emergency. There are even several apps available for your smart phone that give solid first aid advice.
The outcome of the incident above was a good as you could hope. His hiking buddy was calm and solicited help from other hikers, one of which had some aspirin in his pack. They had cell service and could call 911 and the victim was flown to a hospital where a stent was put in. (If no phone service, have a 2m rig with the local repeaters in the memory) He is much better and should be able to get back to climbing soon. His recovery is due, in no small part, to the alert reactions of those around him.
So go make that appointment.