I was giving a talk recently about wellness and health. The audience was lively and engaged. When I mentioned to the audience that a regular morning walk at steady pace was not that useful, I stirred up a hornet’s nest. Every Doctor asks you to walk in the morning or evening for a while, they yelled in unison. I demurred and made an attempted to explain my point.
My quarrel was not with walking. Doing anything physical is better than not. Instead, I was attempting to explain the value of a concept called progressive overload. Coined by Thomas Delorme, M.D. while rehabilitating soldiers from World War II, progressive overload encapsulates the science of maintaining and building the strength in your body. These principles involve continually increasing the demands on your body to help them make gains in size, strength, endurance, and flexibility. Few people have tested the tolerance of the human body, and it is unlikely that you and I will.
The science of increasing the difficulty of what you are doing is not limited to strength training but also extends to cardiovascular exercise. The principles involve several measures. First, you increase the resistance. If you are lifting ten kgs, you raise it to fifteen. Or if you are running, you start to run uphill. Next, you increase the repetitions. Third, you increase the volume which in everyday language is just doing more of the same thing. Forth, you increase frequency which means instead of training every other day; you train every day. Finally, instead of taking the five-minute coffee break in between, you rest for say only thirty seconds.
Combined, this effect on your body is to increase your muscle and bone considerably. Also, your lung capacity grows as your body learns to provide increased oxygen. Which brings me walking. Walking for the same duration at steady state just results in adaption. After the initial gain, your body stops benefitting.