A healthy fitness level is the result of exercise. Some people get their exercise on the job. For example, commercial fishermen can spend months hauling 300-pound fish around. Nurserymen are often in excellent shape for doing the same thing with sod, trees or shrubbery. Low-tech farmers get their exercise by working the land by hand. In America and many other industrialized countries, most people need an exercise regimen to counter the effects of sedentary jobs.
Exercise can be aerobic or anaerobic. In aerobic activity, the body needs oxygen due to prolonged exertion. Such exercises include running, swimming, soccer, basketball, fencing, and dance. These activities have many benefits including decreasing cholesterol levels and blood pressure, improving muscular endurance, reducing body fat, strengthening heart and lungs, strengthening bone, ligaments and tendons and combating depression. Anaerobic activity usually consists of high intensity short, punctuated bursts of activity, but it can also include isometric exercise. It also occurs when the body's demand for oxygen exceeds the supply.
Anaerobic exercise promotes muscular strength. Examples of anaerobic activities include weight training, football, and tennis. While most of these sports involve some aerobic activity during games, the aerobic activity is not constant. Most aerobic activity in these sports is acquired during the sports training.
A combination of aerobic and anaerobic exercise is often the most effective means of maintaining a noncompetition fitness level. Both competition and noncompetition atheletes use a combination of anerobic and anaerobic exercise. Boxers and fencers also train on weights; football and volleyball players run, and soccer players perform isometrics. Combination regimens strengthen the heart, muscles, and overall fitness level.