Aerobic fitness means increasing how well the body uses oxygen, which depends on the condition of the heart, lungs, and muscles. Experts tend to describe aerobic activity in three ways: light, moderate, and vigorous.

When people do vigorous-intensity activities, they breathe faster and have a much faster heartbeat than at rest. To get the benefits of vigorous activity, a person can:

• Jog or run.
• Cycle fast (at least 12 miles per hour [mph]).
• Hike.
• Play soccer.
• Cross-country ski.
• Swim moderately to hard.
• Play a game of basketball or volleyball.
• Carry heavy loads, such as bricks.

The goal of aerobic fitness is to increase the amount of oxygen that goes to the heart and muscles, which allows them to work longer. Any activities, including many kinds of daily activities, that raise the heart rate and keep it up for an extended period of time can improve aerobic fitness. If the activities are done regularly and long enough, they can help improve fitness.

Experts recommend that adults try to do vigorous activity for at least 1¼ hours a week. Or they can do moderate activity for at least 2½ hours a week. People can choose to do one or both types of activity. And it's fine to be active in shorter periods of time throughout the day and week that add up to the recommended goals. Children as young as preschool age benefit from being active. It's best for teens and children (starting at age 6) to do moderate to vigorous activity at least 1 hour every day.

It's always a good idea to talk to your doctor before starting an exercise program.