29 Exercise: Get Moving!-Low

Exercise: Get Moving! FOCUS Question How does exercise affect your body's systems?

Get a Move On! When you ride your bike play soccer, swim, or do push-ups, you are doing exercise. You've probably heard that exercise is good for you. But do you know exactly why it is good for you? During exercise your body works harder. Over time, this extra work makes your whole body, including your brain, stronger! There are four main types of exercise. Each one affects body systems in different ways. All four are important to your health. Read about them on page 3.

Four Categories of Exercise Aerobic exercise is any exercise that makes you breathe faster than normal. It makes your heart beat faster. Dancing and jumping rope are aerobic exercises. Strength training involves lifting, pushing, or pulling weight. It involves short bursts of hard exercise. Push-ups and lifting weights are examples of strength training. Stretching involves moving muscles to their full length. Yoga is a kind of stretching exercise. Stability training involves keeping parts of your body steady while you move other parts. Walking on a balance beam and yoga are examples of stability training.

Healthy Heart Your heart works all the time because your body needs oxygen to stay alive. When you are active, your heart works even harder. That's because your muscles need extra oxygen. Circulatory system to the rescue! This body system includes the heart, blood vessels, and blood. During exercise, especially activities like running and swimming, your heart beats faster to pump more blood to muscles. Blood vessels become wider. As a result, they can carry more blood and oxygen to cells in your muscles. Do You Know? Humans have about 96,560 kilometers (60,000 mi.) of blood vessels in their bodies. That's more than twice the distance around Earth!

If you exercise regularly, your heart muscle becomes stronger. Your heart can pump more blood with each beat. Each beat then delivers more oxygen to your cells. A stronger heart doesn't need to beat as many times each minute. It doesn't have to work as hard when you are resting. This is why exercise is so good for your heart. Regular aerobic exercise can also cause new capillaries to grow. These tiny blood vessels carry oxygen to every cell. Your muscles get more oxygen even when you are not exercising.

Muscle Power Skeletal muscles are the ones attached to your bones. When you exercise, these muscles do most of the work. They allow your body to run, jump, stretch, and move things. Exercise helps skeletal muscles in many ways. During exercise, more blood flows to the skeletal muscles. In addition to oxygen, the blood delivers glucose, a type of sugar used for energy. Some exercises cause your muscles to work and move faster than your body can produce glucose Your muscles can get sore as a result. THREE TYPES OF MUSCLES Type of Muscle Location in Body What It Does Skeletal muscle Attached to bones Moves the body by pulling on bones Smooth muscle Many internal organs Moves liquids and solids through organs within the body Cardiac muscle Heart Pumps blood through the body