Cardiovascular training such as walking elevates the heart rate and increases the strength of the heart, which in turn allows for greater blood flow through the blood vessels. Cardio training is any exercise that elevates your heart rate to a range between 60 to 85 percent of your maximum rate (fastest your heart could possibly beat). When you're in this heart rate range, you're training in an "cardiovascular" or "aerobic" state. Cardio training has numerous health benefits. In addition to burning calories and losing body fat, it strengthens your heart and lungs. Since heart disease is the leading cause of premature death for both men and women, cardiovascular fitness is extremely important.