Running, walking, biking, swimming are all the most important exercises or physical activities you can ever do for your body. Personally, I am a runner, always have been, always will be. I enjoy the other activities but not nearly as much as I do running. There is no feeling like finishing a run let me tell you.
The significance of running is not just physical but mental too. You learn a lot about yourself over the many miles that you may come to run. A lot about your grit, your character, your limits, the list goes on and on. I run everyday, and if you check out the beginner program there is a nice plan set to ease anyone into running or even the other exercises that I listed above.
Your heart is the most important muscle in your body. Cardiovascular activity is the best way to exercise your heart and strengthen it. Along with that cardiovascular exercise strengthens your lungs, and your veins as well as your muscles. It is a full body workout in the truest form of the phrase. I think it is essential to perform some sort of cardiovascular work every day, with appropriate rest and recovery of course. Overtime, when you progressively improve your abilities, your body will become acclimated to the every day work, and will crave it. Me? I run everyday, some weeks I run 5 miles every day, some I only run one or two. Nevertheless, I move my body, get my heart racing, blood pumping, lungs working every day... and you should too!
SK