First a personal question. Do you exercise regularly? I have a hunch some of you do, and
some of you don’t. That’s fine. All are welcome here. Does exercise improve health? Lets see.

     Over twenty five centuries ago, a well-regarded physician observed “All parts of the body,
 if used in moderation and exercised in labors to which each is accustomed, become thereby
 healthy and well developed and age slowly; but if they are unused and left idle,
 they become liable to disease, defective in growth and age quickly.” (Hippocrates,
5th century BC)

     A lot of sweat has oozed out of pores since that good physician offered his opinion. And
he was on to something! Today legions of researchers are studying bodies in motion all over the
planet. Here is one tidbit that surprised me. In a 2017 review highlighting the far-reaching health
benefits of physical activity, the authors noted that they had cited only a fraction of the
>100,000 studies showing positive associations between the terms “exercise” and “health.”
(1). Do you find more than 100,000 positives to be a convincing number? I do.

      Because this is only a glimpse into the field, we will ignore that pile of reports, the tons of studies
ranging from data collection on people going about their daily lives all the way down to
others examining the chemistry percolating within our individual cells. To give a single example,
one clever group investigated the development of coronary heart disease in bus drivers, who
naturally sat on their duffs while working, compared with their actively walking colleagues
(conductors on the same buses). Short result? The drivers developed more coronary disease than
the conductors.    

     Since that time, a flood of research has revealed that physical inactivity is associated with
the development of some 40 physical disorders, including type 2 diabetes, various cancers,
premature aging, strokes, and hypertension, to mention only a few.

     Despite all the evidence demonstrating the value of exercise, other information reveals
that most adults and many children lead relatively sedentary lifestyles (2). According to various
articles, such individuals are not active enough to achieve the health benefits of exercise, benefits
that reach essentially every organ in our bodies.

     Because I am determined to be brief, I’ll touch on just one of the benefits that sedentary
individuals miss out on, the happy effect of aerobic exercise on the brain. When I was in medical
school, back in the age of dinosaurs, we were taught that the brain’s cells and structure were
pretty much unchangeable, that once connections were made in neural tissue, they were set in
concrete, so to speak.

     Now we know better. The brain now is lauded for its neuroplasticity, its ability to adapt to
changes it perceives. Our entire nervous system alters its activity in response to what is going on in
our bodies, and around us. In response to all of these stimuli, structures are reorganized,
connections are rearranged, and our brain and nerves adapt (3).

     As you’ve probably guessed, one of the stimuli affecting the brain is exercise. This is not a science
course, so we aren’t going to worry about details, but I will quote one key sentence from a recent
scientific article, one that summarizes thousands of experiments. Here it is. “Chronic aerobic
exercise has long been shown to improve quality of life.”

     Below is a figure taken from the same publication (4), a figure that diagrams the effects of
long-term aerobic exercise on the functioning of our brains. The figure even traces the links of everything
involved, starting with molecules and ending with our resultant behaviors.

     There you have it, a brief review of the benefits of exercise in under 700 words. This
level of understanding is deep enough for me, but if you would like to dig further, the references
I’ve provided above should provide your shovel. And you may recall that I’ve mentioned
exercise in early posts (5,6).

      If things work out, next time I’ll take a brief look at the effects of exercise on autophagy.
Stay tuned.