Kids exercise all the time without even thinking of it. Just being active, like when you run around outside or play kickball at school, is a kind of exercise. What else counts as exercise? Playing sports, dancing, doing push-ups, and even reaching down to touch your toes.

When you exercise, you're helping build a strong body that will be able to move around and do all the stuff you need it to do. Try to be active every day and your body will thank you later!

Exercise Makes Your Heart Happy
You may know that your heart is a muscle. It works hard, pumping blood every day of your life. You can help this important muscle get stronger by doing aerobic (say: air-o-bik) exercise.

Aerobic means "with air," so aerobic exercise is a kind of activity that requires oxygen. When you breathe, you take in oxygen, and, if you're doing aerobic exercise, you may notice you're breathing faster than normal. Aerobic activity can get your heart pumping, make you sweaty, and quicken your breathing.

When your give your heart this kind of workout on a regular basis, your heart will get even better at its main job - delivering oxygen (in the form of oxygen-carrying blood cells) to all parts of your body.

So you want to do some aerobic exercise right now? Try swimming, basketball, ice or roller hockey, jogging (or walking quickly), in-line skating, soccer, cross-country skiing, biking, or rowing. And don't forget that skipping, jumping rope, and playing hopscotch are aerobic activities, too!

Exercise Strengthens Muscles
Another kind of exercise can help make your muscles stronger. Did you ever do a push-up or swing across the monkey bars at the playground? Those are exercises that can build strength. By using your muscles to do powerful things, you can make them stronger. For older teens and adults, this kind of workout can make muscles bigger, too.

Here are some exercises and activities to build strong muscles:

Exercise Makes You Flexible
Can you touch your toes easily without yelling ouch? Most kids are pretty flexible, which means that they can bend and stretch their bodies without much trouble. This kind of exercise often feels really good, like when you take a big stretch in the morning after waking up. Being flexible is having "full range of motion," which means you can move your arms and legs freely without feeling tightness or pain. It's easy to find things to do for good flexibility:

• tumbling and gymnastics
• yoga
• dancing, especially ballet
• martial arts
• simple stretches, such as touching your toes or side stretches

Exercise Keeps the Balance
Food gives your body fuel in the form of calories, which are a kind of energy. Your body needs a certain amount of calories every day just to function, breathe, walk around, and do all the basic stuff. But if you're active, your body needs an extra measure of calories or energy. If you're not very active, your body won't need as many calories. Whatever your calorie need is, if you eat enough to meet that need, your body weight will stay about the same. If you eat more calories than your body needs, it may be stored as excess fat.

Exercise Makes You Feel Good
It feels good to have a strong, flexible body that can do all the activities you enjoy - like running, jumping, and playing with your friends. It's also fun to be good at something, like scoring a basket, hitting a home run, or perfecting a dive. But you may not know that exercising can actually put you in a better mood.

When you exercise, your brain releases a chemical called endorphins (say: en-dor-funz), which may make you feel happier. It's just another reason why exercise is cool!