The physical benefits of exercise extend to many of the systems in your body.

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1 13.1 The Benefits of Physical Activity How physically active are you? To answer this question, you first need to know that physical activity includes more than just sports. Any movement that requires your large muscle groups to work is considered Thus, physical activity includes actions such as walking briskly around the mall or doing household chores. Teens should spend 60 minutes or more each day performing some form of physical activity. What happens inside your body when you rake leaves, swim, or dance? The most obvious changes affect your heart, lungs, and muscles. But did you also know that chemical changes occur in your brain that influence your mood? The changes that occur due to physical activity are beneficial to your body, your mind, and your social interactions. Physical Benefits The physical benefits of exercise extend to many of the systems in your body. _ Cardiovascular System Your heart and blood vessels receive the most benefits from regular physical activity. As your heart becomes stronger, it can pump more blood with less effort. The number of capillaries in your muscles increases, which may reduce blood pressure. Exercise also lowers blood cholesterol levels. _ Weight Maintenance Regular physical activity increases your basal metabolic rate the amount of energy your body uses when you are at rest. An active metabolism makes it easier to remain at a healthy weight. Staying at a healthy weight can reduce your risk for developing diseases such as diabetes, heart disease, and certain cancers. Bone Strength Your physical activities should include some weight bearing exercises such as jumping rope or walking. These activities make your bones stronger and denser. Having strong, dense bones may reduce your chances of developing osteoporosis later in life. _ Balance and Coordination Physical activity improves your balance and coordination, which may, in turn, improve your athletic ability. In addition, good balance and coordination can also reduce your risk of injury while performing chores such as climbing ladders or carrying packages down stairs.

2 Psychological Benefits During continuous exercise, your brain releases chemicals that block pain messages from reaching your brain cells. Endorphins are also responsible for the feelings of satisfaction and pleasure you feel after a good workout. People who exercise regularly are likely to be more self-confident and focused, and have reduced stress levels. Simple stretching exercises, for example, can relax tense muscles and help you sleep better. If you are upset or depressed, physical activity can help improve your mood. In fact, Types of Physical Activity No single activity can improve or maintain all five components of fitness. Instead, it is important to participate in a variety of physical activities. Physical activities can be classified as aerobic exercise or anaerobic exercise. Strengthening and endurance activities can be further classified as isometric exercise, isotonic exercise, or isokinetic exercise. Aerobic Exercise Ongoing physical activity that raises your breathing rate and heart rate is called (ehr OH bik). Aerobic exercises increase the amount of oxygen that your body takes in and uses. Swimming, running, brisk walking, and cross-country skiing are all forms of aerobic exercise. By performing aerobic exercise for at least 20 minutes at a time on a regular basis, you can improve your cardiorespiratory endurance.many aerobic activities also improve muscular endurance. Anaerobic Exercise Intense physical activity that lasts for a few seconds to a few minutes is called (an uh ROH bik). Because anaerobic exercise is so intense and quick, your cardiovascular system cannot supply muscles with enough oxygen to produce energy. Unlike your other body cells, muscle cells do not need oxygen to meet this rapid demand for energy. Lifting weights, doing push-ups, and sprinting are examples of anaerobic activities. Most anaerobic exercises develop muscular strength, muscular endurance, or flexibility. Isometric Exercise Place your palms together and push them against each other. This is an (eye suh MET rik), an exercise in which muscles contract but very little body movement takes place. If you do isometric exercises on a regular basis, the muscles you use will become stronger. Isotonic Exercise (eye suh TAHN ik) involves contracting and relaxing your muscles through the full range of a joint s

3 motion. Pull-ups are an example of isotonic exercise. Exercises with free weights, such as barbells, are also isotonic. Through repetition of isotonic exercises, you can develop muscular strength and endurance. Isokinetic Exercise In (eye soh ki NET ik) muscles contract at a constant rate. Isokinetic exercises require fitness machines that provide resistance to muscle movement. These exercises are often used as therapy to rebuild muscle strength after an injury. many health professionals consider physical activity an important part of treatment for depression. Social Benefits Exercise is also an opportunity to have fun.whether you play on a sports team or join an aerobics class, physical activity can be a way to bond with family and friends or build new relationships The Components of Fitness Most people do not have the ability to become an Olympic swimmer or a professional football player. But, with dedication, just about everyone can be physically fit. means that you have the energy and strength to participate in a variety of activities. There are five components of fitness: cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, and body composition. Cardiorespiratory Endurance Cardiorespiratory endurance means that your heart, blood vessels, and lungs are able to distribute nutrients and oxygen and remove wastes efficiently during prolonged exercise. People with poor cardiorespiratory endurance become short of breath and have a very high heart rate after even light exercise. Regular exercise improves cardiorespiratory endurance. As the heart muscles become stronger, more blood is pumped with each beat. The lungs become more efficient at delivering oxygen to the blood and removing carbon dioxide. Muscular Strength The capacity of a muscle or a group of muscles to produce force is called muscular strength. The amount of weight you can lift is one measure of your muscular strength. You need muscular strength for most sports and everyday activities. Muscular Endurance Muscular endurance is the ability of your muscles to work for an extended time.how long you can hold a barbell or how many times you can lift it is a measure of your muscular

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