Have you ever danced, swum, roller skated or participated in other physical activities that you thoroughly enjoyed? All these pastimes qualify as cardio, or aerobic, exercise, but chances are not one of them made you feel like you were doing hard work.

To qualify as cardiovascular exercise, an activity must raise your heart rate (beats per minute) to between 50 and 70 percent of the maximum you can endure during physical activity. (To calculate your maximum heart rate, subtract your age from 220.) Each of the previously mentioned activities meets this requirement.

Aerobic exercise positively affects the entire body, boosts mood and energy levels, promotes better sleep, releases stress-taming hormones and builds a stronger immune system. To reap these head-to-toe benefits of cardio, experts suggest people walk, run, bike, row, climb stairs, jump rope and engage in circuit training.