It seems that there are many aspects that affect heart health. Exercise, diet, stretching, etc. What is most important to start with? I recommend to get diet in order first. Drink more water, keep moderate carbs and lean protein, cut out as much fat as you can except for omega-3 (fish oil especially). Then work stretching and identifying tight spots in the body(these are roadblocks to overall vascular flow). Then add in moderate cardio exercise. Too much exercise at first will throw hunger pangs and muscle stiffness your way. Heavy weight training can also lead to tight muscles. Slowly add longer and more intense workouts as it becomes easier and more fun. Over time(maybe years), these will turn into habits. Perhaps you will find in the off season(too hot, too cold, too wet) is a good time to address diet and stretching, while exercising outdoors as much as possible during the good seasons. I find a good balance of all three throughout the year to be best.