The basic components of fitness include cardiorespiratory endurance, muscular strength, muscular endurance, and flexibility. To be truly fit, aerobic, stretching and resistance exercises should be part of your fitness plan.

Cardiorespiratory fitness improves the health and function of the heart, lungs and circulatory system by increasing the capacity of the lungs to exchange oxygen and carbon dioxide with the blood, while improving transportation of nutrients and waste products to and from the body's cells.

Resistance training, such as lifting weights, improves muscle strength and endurance. Yoga and stretching increases your flexibility and prevents injuries. Together, these exercises improve circulation of blood and nutrients throughout the body, strengthen bones and protect against chronic diseases.

An effective fitness program can be designed by using the FITT principle: Frequency, Intensity, Time, and Type of activity. For the best program for you seek out an ACE (American Council on Exercise) Certified Trainer. If you have medical issues, exercise programs need to be adjusted. A Certified Medical Exercise Specialist can help you develop an exercise plan that is safe for you.