Bloody hell, some people really do seem to give up. I'm 55 and have a resting heart rate of 48, which is athletically fit. I cycle 50-60 miles at weekends with around 3000 ft of climbing and have never had any serious illness. I expect to be doing the same well into my sixties and possibly seventies unless I lose my marbles.
Regular exercise, no smoking and moderate booze are the secret.