Testosterone in the body is either "free" or "bound." Free testosterone is also known as circulating testosterone. Free testosterone levels generally decrease with age and may have functions that relate to your physiological and psychological health. Free testosterone levels may relate to exercise capacity. Men with chronic heart failure and lower levels of free testosterone have higher exercise intolerance. Some researchers believe that free testosterone is the only testosterone that really counts, since it is the testosterone ready and able to actually "work" on your tissues. And there is a lot of truth to this. However, other experts counter that total testosterone is really the better number, because it acts as reserve or bank to build from. Well, I will leave...
