Aerobics is popular because it has the appeal of dance, offers the companionship of a group, and costs very little. The combination of calisthenics with repetitive dance routines allows you to improve your heart health. Step aerobics offers a high cardiovascular workout with low body impact. Stepping represents the aerobic equivalent of a 7-mile run and the impact equivalent of a 3-mile walk. Add hand weights and you can develop your arms and upper body as well. Water, or aqua, aerobics is hard on the muscles and soft on the joints, and allows you to reach a greater range of motion than you can on land.