These terms are often used interchangeably. Although they all relate to quality of life, they don't necessarily mean the same thing. The definition of health is being free from illness and injury. Notice it doesn't refer to fitness in any way. So it's possible you are in good health (meaning not sick or hurt), but that doesn't necessarily mean you are physically fit.

Physical fitness is sometimes defined as the ability to perform sustained activity without an excessive amount of fatigue. It's very likely that someone who is physically fit has a high degree of good health.

Wellness is a popular and more main-stream term for being in good physical and mental health. It includes the physical, emotional, spiritual, environmental, and social aspects of life. Everyone should be concerned with all aspects of health and wellness because they are so closely related to who we are, what we feel, and how we behave. Each one of these components can directly affect the others in a positive or negative way.

For example, if you are having difficulties at work, this can affect whether you're in the mood to meet up with friends after work. The next day you go back to work only to find more difficulties. This drains your energy even more, so you don't feel up to going to the gym. This domino effect is a common obstacle in training. The same is true on the other side of the spectrum.

You may receive a big promotion at work and become enthusiastic in your new position. You become more social, get in touch with your spirituality, and begin training more frequently. The more aware you are of what triggers your moods, the more you will be able to make them work for you instead of against you.

There are many ways to measure your level of fitness. The term fitness is actually a very broad term. In this case, it's the condition of being physically fit — the ability to perform physical activity in which the heart rate increases and having the ability to sustain that level of intensity for an extended period of time.

With the integration of health, wellness, and fitness into your life it's no doubt that you will look better and feel better. This can be considered a way of living or a way of being that many would term as having a “healthy lifestyle.” Individuals who prefer the healthy lifestyle way of living tend to live happy, long, prosperous lives and feel good about their choices in life.