Cardiovascular or endurance training should be the heart and center of every good training program. Cardio training is defined as a sustained exercise (an action that you perform for a long period of time). The goal of cardio training is to raise you heart level to a target range for a certain amount of time (usually 30 minutes to an hour). When most people think of cardio training they think of burning fat, but there are other benefits that are appatitizing to other people who are not just trying to lose some extra fat.
Cardiovascular exercises help stimulate the blood flow in our body which helps increase the number of red blood cells (Red blood cells carry oxygen to the organs via our veins). Any aerobic exercise helps increase the bodies desire and need for oxygen which then will help strengthen out cardiovascular system. You should look at you heart as a muscle, and cardio is the way to strengthen that muscle.
Cardiovascular exercise also has a mental effect. Exercise will help reduce Anxiety and Depression. Studies have shown that effects on anxiety reduction are greater when the person is partaking in aerobic activities (such as running or biking), when the length of the aerobic program lasts at least ten weeks, and when the person has a lower level of fitness or a higher level of anxiety. Exercise was proven to have longer antidepressant effects when the program lasted for over nine weeks and the exercise was a longer duration, and repeated multiple times throughout the week. (source http://www.fitness.gov/mentalhealth.htm)
Cardiovascular fitness is in my opinion the most important area of fitness. If you are an athlete working on cardio will greatly improve your endurance and it will help you stay focused and fit on the field. If you are just exercising to stay healthy, cardiovascular fitness will keep you happy and healthy by having both a positive effect on your body and you mind.
