Few people know how exercise works, but there is one clue, and it is in a specific little–known hormone.

How many hormones or neurotransmitters do you know? Which are the ones you hear about most frequently? You're probably familiar with dopamine and serotonin. They're linked to anxiety, depression, and other mood disorders.

Pharmaceutical companies have given us a great deal of information sometimes causing confusion when we think about neurotransmitters. But, outside of pharmaceuticals, there is another way we can help ourselves to better health. Exercise is one way researchers have discovered we have influence over crucial neurotransmitters.

Whoever thought that exercise could have such dramatic effects on our ability to maintain brain health? Well, the jury is in on that one, and the gains are impressive—gains that we cannot ignore. The good news is that you don't have to exercise to exhaustion to reap the benefits. But it's not simply one hormone, dopamine, that is in play here, which can mean gains for all of us.

Of course, dopamine is a complex hormone-neurotransmitter of interest. Exercising raises levels of this hormone associated with motivation, pleasure, and contentment. New research shows a possible link between better reflexes and dopamine levels when exercising. In 1979, researchers found the good news about dopamine and reflexes when they observed older lab rats and their swimming abilities. Once the older rats got the biosynthetic precursor of dopamine, L-dopa, their swimming ability and endurance increased.

As people live longer, and with the risk of Alzheimer's disease affecting their cognition, it's crucial to find ways to prevent cognitive impairments. Despite researchers' best efforts, traditional methods for developing effective treatments have mostly been unsuccessful. Curiously, research has shown that exercise, particularly endurance exercise, can boost cognitive function as we age and has positive benefits in brain health generally.

The hippocampus, which helps with memory recall and recognition, can be modified in young adults through aerobic exercise. A three-month intervention examined whether healthy older persons (60–77 years) also exhibit such flexibility. Researchers have observed a correlation between cognition and exercise in persons in their twenties and thirties, suggesting that it persists into old age. The results? Improvements in fitness were positively associated with improvements in early spatial object recognition and memory.

This research on aerobic exercise and cognition also noted one caveat of concern. As people get older, the benefits of exercise on the brain seem to decrease. This is especially true for the hippocampus, a critical part of the brain.

We need to consider, however, that many intervening variables were not accounted for in this research and may play a major role in older persons' cognitive processes benefiting from exercise. Of course, genetic inheritance, diet, and lifestyle are always issues that need to be considered and may contribute, either minutely or massively, to changes that may come about after these exercise protocols.

One thing we must note is that exercise is always a good idea, and we should not write it off because of one research project. Just because one research study produced an interesting result doesn't mean it applies to everyone.

But what about the hormone irisin that is involved in both exercise and body fat? A slight increase in irisin levels can improve insulin resistance caused by a diet. This hormone can help muscles function better by affecting fat. And there is much more evidence for the involvement of irisin as well as in body fat—white versus brown fat.

Another interesting finding of research on irisin is that it can contain neuroinflammation, which has been thought to be involved in the development of Alzheimer's disease. In fact, neuroinflammation has been viewed as the major killer of brain neurons as we age.

To date, all of this research is bringing new attention to the complex relationships in our bodies. The intricate muscle-fat-bone axis now includes skeletal muscle, which is thought of as an endocrine organ that secretes irisin. This may be a little–known hormone that has a major effect on our body overall.

Developments in the understanding of the skeleton’s role as an endocrine organ in glucose tolerance and testosterone production through the secretion of a bone-specific protein are encouraging. Now that bone-skeletal muscle is officially recognized as an endocrine “gland,” the therapeutic possibilities for this hormone-secreting tissue are endless.

The main point is that exercising regularly is crucial for our health and mental abilities as we grow older, and we are only now beginning to fully appreciate its importance. The overall maintenance of our bodies goes beyond just keeping our muscles in shape. Anyone who can sit in a chair can exercise. Don’t believe it? Go to YouTube and watch this video.