Thinking about beginning an exercise program? Congratulations! Few decisions are packed with so many rewards for body and spirit. Exercise can give you more energy, improve your self-image and boost the odds of remaining healthy over the long haul.

However, before slipping into those new sweats and lacing up your running shoes, beware the potential pitfalls that await all new athletes. There are countless errors that people make when they exercise. Avoiding these mistakes can leave you less vulnerable to injury and more likely to stay motivated and stick with your routine.

Five common fitness mistakes and how to avoid them:

Trying to do too much, too soon

It's normal to dream of nervously shuffling into your first workout as a 90-pound weakling only to emerge a month later as a confidently striding, ripped new Madonna or Usher. Unfortunately, reality usually is somewhat less grandiose, at least initially.

Moderation is the key to success when beginning a new exercise program. Trying to pump too much iron too quickly can result in a serious injury. Going from couch potato to marathon runner overnight is far too hard on the body's muscles, tendons and joints.

Instead, begin slowly. A basic 10-minute walk around the neighborhood is an excellent introduction to cardiovascular fitness. Meanwhile, doing a few pushups at the foot of your bed (either with your toes extended or from the knees) can kick off a new strength-training regimen.