First post and questions for those with more experience than me.
I have an itch to old-school hunt bison, moose and elk. I traded my way in to an '85 Winchester (Miroku) High Wall in 45-90. Things being what they are, I promptly had a stroke and two heart attacks right after acquiring the rifle. Luck of all luck, I now have a clean bill of health with no effects from either incident. Fast forward to now and the itch is stronger than ever.

The High Wall weighs in at 8 1/2 pounds. 45-90 recoil being what it is, I have been advised I should consider either obtaining a heavier rifle or step down in caliber to reduce the risk of triggering another stroke or heart attack.

What do others think - is it good advice or is it over-reactive?
I will say it sounds like a perfect reason to buy a Shiloh, which I am prepared, and more than willing to do (I can almost hear a Shiloh Rough Rider calling my name).

For me while hunting, I never even feel the recoil when I take a shot at game, even a rifle/shotgun with heavy recoil.  Now target shooting is entirely different, I don't like recoil at all.
However, nothing wrong with buying a new heavier rifle for less felt recoil. 
It's a very good excuse for buying a new rifle.

"talk to your physician and see what he/she tells you" - LOL, he is the one who warned me. He also said nothing with the word 'magnum' in it!

I told him he worried too much. Convincing my wife may be another story!

I have a Montana Roughrider in 45-90 and it weighs 10 1/2 lbs. with a half octagon/half round barrel and I forget the length but I think it is 30 inches.  I shoot 80 grs. of Schuetzen under a 480 gr. NEI bullet.  Off a bench yes, the recoil is noticeable but, being black powder it isn't sharp like smokeless.  It was the only rifle I hunted with for 12 years and is still the most effective cartridge I have used in 60 years of hunting deer and larger game.

I don't know what to say about what your doctor told you but here's what my wife did.  10 years ago she had a brain tumor and subsequent surgery when a titanium plate was installed in her head to hold her left eye in place, then 19 days of radiation.  She just told me it was August 12th.  I believe it was in October she had a follow up and asked her surgeon if she could deer hunt.  He didn't know what to say nor did any of his associates.  We immediately assumed that they, being big city doctors, had evidently never been around firearms or hunted anything in their life.  I tried to explain to them the ft. lbs. of recoil developed by a fairly light loaded 243, thinking that might be something they could relate to.  Dumb looks around.  Finally they decided it would be ok.  By the time our deer season got here in late November she was ready and killed a deer about the middle of the season.  She missed the first deer she shot at because she was concerned about the cheek weld and recoil.  She said it wasn't anything so the next deer she saw she knuckled down and drilled it.  That was he 8th or 9th deer.

I have no idea how that correlates to heart issues.  Be that as it may the recoil for her was a whole lot closer to her brain than her heart and she's fine.  She's subsequently killed a couple more deer before her rheumatoid arthritis took away her ability sit in a stand or tolerate cold weather.  Every year she thinks she might try again and, I hope she does....if she just wouldn't shoot the darn things right at dusk!!!!  I stopped hunting afternoons and evenings 20+ years ago because I hated field dressing and hanging deer that late in the day.  I've just about quit hunting completely.