Exercise is Good—But Why, Exactly?
Of course, just about everyone knows that in order to stay fit and healthy you’ve got to get up and move. Sitting is now recognized as a toxic behavior. Virtually any type of movement is good for the heart and muscles. Exercise provides numerous benefits, from a better-functioning immune system, to a reduced incidence of obesity, to a lower risk of depression and other illnesses.
You’re never too young or too old to get up and move it. In fact, the more often you engage in physical activity throughout your lifetime, the longer you’re likely to live.
But why, exactly? What is it about exercise that triggers so many beneficial changes in the body? When it comes to heart disease, experts have long speculated that exercise promotes cardiovascular health through a number of mechanisms. Simple mechanical sheer stress caused by rushing blood cells coursing through the blood vessels is thought to influence the status of the delicate tissues lining the vessels—tissue called the endothelium.
Most heart disease begins slowly, at the cellular level, in the endothelium. When this tissue becomes unhealthy, a condition called endothelial dysfunction sets in. It’s the first step towards atherosclerosis, which can eventually lead to heart attack and/or stroke. The simple mechanical stress caused by rushing blood, which speeds up during exercise, is thought to mediate some of the blood vessel (and, thus, cardiovascular) benefits of exercise.
But it goes even deeper than that. In essence, exercise rewrites our DNA, invariably in a good way. At least, that’s the conclusion of a new study, which reports that the relatively new science of epigenetics explains these effects.
Of course, DNA is the genetic blueprint we’re all born with. And, just as you were taught in school, one’s DNA code is immutable. You got the unique combination of genes that make you you from your parents. And nothing will ever change that coding. It’s “set in stone,” if you will. But in recent years, scientists have discovered that it’s not quite that simple. There is, in fact, a mechanism in place by which external factors—environmental effects—such as the foods we eat, the exercise we do or don’t engage in, chemicals we’re exposed to, etc., can affect the “expression” of the genetic code.
Expression simply means the ways in which certain bits of code are translated into proteins, which in turn circulate throughout the body and influence everything from the workings of the immune system to how fat or thin you—or your descendants —will be. Certain environmental factors—such as foods, exercise, or toxins—can cause changes to occur to this “epigenome.” In essence, this causes “switches” to be turned on or off. In this manner, although the underlying code remains the same, the way in which the body “reads” the code is altered. These tweaks to the code can even be passed down to one’s offspring.
Exercise causes beneficial epigenetic changes. Some of these can be passed down for generations, meaning that the daily choices you make about your own health may actually reverberate down through the generations, influencing your grandchildren’s risks of everything from diabetes to heart disease. So, no pressure!
Do you enjoy exercising? What’s your favorite workout? I’d love to hear your feedback.
Lindholm ME1, Marabita F, et al. An integrative analysis reveals coordinated reprogramming of the epigenome and the transcriptome in human skeletal muscle after training. Epigenetics. 2014 Dec 7:0. [Epub ahead of print]