Tarantonight, I get your point. I admit I was confused until I got to the end of your post as, if you read back a bit, you'll find I've been banging that same drum here, probably too much.
Jayand, again something I touched on here a few pages ago. I refer to the USAF medical folks that once tortured me in their centrifuge during my time flying the F-15. To cut a long story short, their extensive research has not revealed any significant difference in resting or straining g-tolerance between twenty-somethings and fifty-somethings. Interestingly, there are some differences between gymn weight-pumpers, regular runners and folk that simply do regular exercise - and not necessarily those you might expect. But that is a different issue. Age is not a significant factor in g-tolerance.
As for medical exams, the requirements are clear and medicals are required for all pilots, civil and military. Whilst there is no difference between a pilot wanting to fly in straight lines and one that wants to do aeros, the standards are strict.
Yes, medicals include ECGs, blood tests, hearing tests, eye tests, urine tests and some other stuff.
Yes you do see a lot of pilots flying high performance aircraft well into their forties and fifties - as long as they are physically fit to do so. Some of us even managed to walk, unaided, to the aircraft.
I would be interested to hear back from you on this because I suspect you have some doubts and, perhaps, misconceptions in this area that I would be happy to address further if it would help.