Fitness is a measurable state or condition partially determined by genetics. Health is also a condition but is not as easily measured or defined as fitness. Health is not merely the presence or absence of disease; rather, it’s a complete state of physical, mental, and social well-being, a complex of factors that represents all levels of vitality from the highest to the lowest (or death, to put it bluntly).
On the other hand, the World Health Organization (WHO) defines fitness as “the ability to perform work satisfactorily,” thus making the definition of who is fit and who isn’t somewhat dependent on personal inclination and social context. One’s ability to perform work satisfactorily depends on the type of work involved and on how one defines "satisfactorily."
To a competitive runner, for example, fitness is measured in faster times and longer distances; fitness means fit or conditioned for beating the other guy, the clock, or one’s previous best. To the Olympic athlete, fitness is ultimately measured in terms of gold medals and world records. To the plodder, fitness is measured perhaps in simply getting through the next mile.

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Lifefit: An Effective Exercise Program for Optimal Health and a Longer Life
Fitness is a sub-category of health. Fitness involves cardio and strength training. In order to be fit you need to incorporate strength and cardio into your workouts. However, it is possible to be fit and not healthy. You could workout 5-6 times a week and smoke and eat a high fat diet. Fitness is measured in vanity terms whereas health is measured with cholestorol numbers, blood sugar levels, blood pressure levels, etc.
My recommendation is to work on being health by watching what you eat, watching your weight, and make sure you don't eat alot of salt to prevent hypertension. In doing so, you can then work on your fitness level by exercising.
Regarding fitness: let's just say someone can eat crap and still look fit because they are disciplined with their exercise regime.
Regarding health: someone can be very healthy and still struggle with their weight because they don't like to exercise or are exercising inefficiently.
Fitness and health can be viewed in many ways. Often time’s people may describe good fitness as being healthy and active. Some differences between the two terms include but are not limited to the following. Fitness is a state or condition of being physically active. Fitness is a result of general nutrition and proper conditioning, and fitness is a state of general physical and mental well-being.
Health is a much broader term and will vary from individual to individual. People may describe themselves as healthy but that will depend on your description of what you feel is healthy. Having an average or below average body mass index (BMI) may classify you as being healthy. Keeping your body fat percentage below a certain number may also assist you in being healthy. Health can include being free from disease and injury. Again, health has a much broader outlook and can vary.
Essentially many differences are present between the two but plenty is open to discussion. Your main goal should be to keep high levels of fitness which should help result in a healthy lifestyle along with sound nutrition.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.