When you look around you or watch the world go by from a relaxing vantage point, you will notice there are many very healthy people walking by. They are the ones with a spring in their step and a smile on their face, or an expression of contentment and happiness. Then there are those with not so great health but still fully mobile and active. They have a less bouncy step and maybe the smile is missing, but in general they are relatively happy with their lot. Then there are those with obvious health issues. Their pace is slower, their gate less stable. There is usually a stern or worried look on their face and the general outward appearance is one of stressed dejection.