On one steady-state cardio training day each week, substitute swimming for your regular cardio workout. Swimming works all the major muscles in the body, including the heart. Unless you swim regularly, expect to feel some initial soreness in the arms, chest, shoulders, and legs.

A 150-pound person can expect to burn approximately 432 calories an hour while swimming at a moderate pace. More vigorous swimming can burn as many calories as running 10 miles in an hour (720 calories) and places much less stress on the joints. Comparatively, while walking, a 150-pound person will burn approximately 334 calories an hour maintaining a 15-minute mile pace, or 576 calories if walking at a 12-minute mile pace.

Adding swimming to your workouts does more than burn excess calories, however. It also adds a cross-training component, which helps prevent injuries and stimulates your muscles to adapt to new activities. Give swimming a try -- you may just discover a new favorite activity.

*Interval: 30-second dash followed by a 30-second to 1-minute recovery