Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Physical exercise is any bodily activity that helps to enhance or maintain physical fitness and overall health. There are various reasons to perform physical exercise. Those includes strengthening muscles and the cardiovascular system, increasing athletic skills, weight loss or maintenance, as well as for the purpose of enjoyment. Regular physical exercise boosts the immune system and helps prevent the diseases of affluence such as heart disease, cardiovascular disease, Type 2 diabetes and obesity. Physical exercise is also thought to improve mental health, help prevent depression, and promote or maintain positive self esteem... Learn more about physical exercise, physical fitness and common injuries that can occur during physical exercise.