Some people say that exercise keeps you healthy and increases longevity. Others say it puts you at risk of injury and premature aging. What's the real deal with exercise? This article will give the real deal -- as well as bust a few myths about exercise that simply too many people believe.

Long story short -- exercise can either be a blessing or a curse, depending on how you do it. Exercises can actually be bad for your health when you do them wrong, or when you limit yourself to certain types of exercises. Here are a few examples:

#1 - Long, slow cardiovascular exercises -- like long-distance jogging. People may tell you cardio is the best way to lose weight, but research and experience has shown that this simply isn't true. Such exercises don't only put you at risk of repetitive stress injury, but it actually makes you hungrier at the end -- which means you end up eating more.

#2 - Too little strength training. You probably know this already, but muscle does burn calories better than fat -- probably better than you think! Strength training will also help you build strength on all parts of your body -- not just those worked out in cardio.

#3 - Too little interval training. Interval training is all about alternating maximum-intensity activity with periods of low-intensity activity or rest. A good example is sprinting. To know how interval training is better than cardio, compare a sprinter's body to a marathon runner's. No match!

But when you exercise correctly -- that is, mixing up cardio, strength, and interval training in every workout, and working out at least three times a week -- you'll keep your DNA young and delay aging by several years. Combined with a good diet, you'll be on your way to enjoying the golden years of life.