Exercise aids fitness in several ways. For example, vigorous physical activity causes the heart muscles to work harder. This leads to increased blood flow throughout the body that helps circulate oxygen to the tissues and also eliminates the cellular waste products from the body.

During exercise, we tend to inhale deeply and thus draw in extra oxygen that not only helps power the heart but also the tissues of the body. When we exhale, we rid the body of carbon monoxide, a waste product produced as a result of biochemical reactions that take place in the body.

Regular and age appropriate exercise helps prevent obesity. It also helps to increase the HDL (High-Density Lipoprotein) levels in the body. HDL are types of good cholesterol that actually benefit the body by regulating the sugar levels and converting the stored fat into sugars thereby producing energy.

Most people exercise with the main aim of achieving a well toned body, increasing muscle mass and to look and feel healthy. It also helps over time to improve balance, strength and increase endurance as well.

There are different exercise routines that aim at developing specific parts of the body. For example, pilates and yoga improve balance, flexibility and muscular control. An aerobic workout helps to activate the cardiovascular and pulmonary systems and weight training focuses on building muscle mass and toning the body. However, even though these exercises target a specific focus group, exercise in general is beneficial for the entire body.

Moderate exercise for just 30 minutes a day, 5 days a week will go a long way in achieving optimal fitness.

There are a variety of simple exercises that can be done without any special equipment or training. These include taking a brisk walk, taking the stairs where ever possible, going for a short jog everyday or even skipping.

For those who prefer more vigorous forms of activity, a good tennis game, running an hour on the treadmill or exercise bike, swimming a few laps around the pool or spinning can help raise your fitness and energy levels much higher.

There are always a variety of classes available at gyms and even home gym equipment that can be bought for people who are committed to keeping themselves fit on a regular basis. A daily routine that involves free weight training and a short jog around the park is enough to keep the body systems functioning well and healthy.

Thus, it has been rightly said by Aristotle that "To function well is to live well".