Most of the things were, as Adrienne mentioned, subtle before the surgery. They came on very slowly, and were nearly imperceptible, and when noticed, easily fobbed off to age and inadequate activity.
As far as the symptoms, we are our own worst enemies when it comes to recognizing them. The changes in our bodies creep up in such slow increments that we don't notice the change. We want to believe in our health, so we move ahead in such denial that we literally do not heed our own bodies' warnings. We tend to second-guess and rationalize our symptoms away.
Getting winded faster, feeling lethargic, poor recovery from colds or flu, trouble sleeping, decrease of "manly abilities," palpitations, increased difficulty handling heat/cold, short of breath at altitudes, general fatigue, and even occasional dizziness are all symptoms that are easily explained away to ourselves.
Another is angina, which is not as easy to recognize as you might think. Angina doesn't always show up when we are exercising, and often shows up as a slight or moderate, uncomfortable tightness at the top of the throat or as a feeling in the top of the lungs like you may get from breathing cold air. It can be a feeling of pressure in the chest, or may be pain that radiates down the back. For women, it's even more difficult to recognize, often showing up as jaw pain. The classic picture of someone clutching at their left side just isn't the case for most.
Best wishes,