When just getting started with a cardio exercise routine, make sure to pick an exercise you enjoy!  The best exercise for you is one that you’ll actually do!...

Cross-training, training in different ways to improve overall performance including cardiovascular, takes advantage of the particular effectiveness of different training methods. 

A general guideline for exercise intensity:  most experts agree that you should exercise at 60 to 85 percent of your maximum heart rate. However people with asthma, heart disease, or other health conditions might need to exercise at 55 percent or less and confirm target heart rate with their physician. You can calculate your target heart rate by subtracting your age from the number 220.