In this topic you will learn about how proper diet and exercise can help you stay healthy.

Through exercise and practice, we can train our bodies to be physically fit. Physical fitness is the condition in which your body is healthy and works the best it can. It involves working your skeletal muscles, bones and joints, heart, and respiratory system.

The more you use a muscle, the stronger it becomes. Even when they are relaxed, toned muscles stay slightly contracted. Your muscles need energy to work and grow. The energy comes mainly from food combined with oxygen. As you exercise or become more active, your breathing rate increases to provide this oxygen. Your heart pumps faster to speed oxygen to your muscles. In time your lungs will take in more air with each breath. Your heart will pump more blood with each beat. They do more work with less effort.

Brisk and constant physical activity that increases the supply of oxygen to the muscles is called aerobic exercise. Aerobic exercises include swimming, jogging, and biking. Aerobic exercises improve your physical fitness if you do them three to five times a week for about half an hour without stopping. As you exercise more, your endurance lets you stay active longer without getting tired. As your muscles become stronger, you lift, pull, and push with more force. Your bones grow thicker and stronger. The energy your muscles use also forces your body to store less fat.

There is more to fitness than exercise. Without a healthy diet, your body cannot work at its best. Among the best sources of energy are the sugars and starches in fruits, vegetables, and whole grains. Your muscles are made of proteins. To keep them strong, you need food rich in proteins, such as meat, beans, and nuts. Your body also needs some stored fat for energy. However, too much fat can harm your heart and blood vessels. Muscles and bones also need vitamins and minerals to stay strong and do their jobs.

To make sure your body has these ingredients, eat a balanced diet. This means a diet, maintained over time, that includes a variety of foods providing nutrition in moderate amounts. A balanced diet includes all the major food groups. Each food group contains foods with similar amounts of important nutrients.