A friend has been an avid cyclist for over 50 years. He's now 66 and is 5'8" and 140 lbs...so, very fit. He's also the best climber I've ever known. One day he was telling me how hard it has been for him to climb. He was struggling to breathe. Even had to walk a hill. Of course he sought out medical help. Long story short he had a quadruple bypass. He has a family history of heart disease. I think it's been about 4 months since the operation and he's back on the bike leading Farm to Fork Fondos here in the northeast and back to his radio show "Bicycle Talk." You are going to be so much better. Best of luck on your new adventure.