This is an excerpt from Ageless Intensity by Pete McCall.
All of the systems in the body are made up of cells. One of the greatest benefits of high-intensity exercise is that it results in mechanotransduction, which is the process of mechanical forces stimulating the production of new cells in muscle and connective tissues. If your car becomes scratched, you may need to apply some paint to cover up the scratch. As you age, high-intensity exercise creates the mechanical forces that can stimulate production of new cells, which is like carrying touch-up paint to fix damaged tissues in your body. Table 2.4 outlines the systems of the body that receive the greatest benefits from exercise.
Exercise is the essential factor you can use to change how the aging process affects your body. The effects of the aging process can greatly diminish the mechanical, metabolic, hormonal, and neural functions vital for energy production and control of the muscular activity responsible for human movement. Mechanical components of the human body include muscle, fascia, connective tissue, organs, and skeletal structures. Metabolic functions control the breakdown of macronutrients for the production of chemical energy (adenosine triphosphate [ATP] ) to fuel muscle contractions. Hormones are produced in reaction to various stimuli in order to control the functions and actions of specific cells. Neural activity senses an external or internal stimulus and determines an appropriate response.
Table 2.2 on page 22 shows what can happen to the bodies of individuals who remain sedentary throughout the aging process; tables 2.4 and 2.5 feature the benefits from exercise. Comparing the three tables, it’s easy to see that the benefits of exercise can address a number of the changes that occur during the aging process. Exercise can’t eliminate the effects of aging, but an exercise program that includes workouts for mobility and high-intensity strength and power training in addition to metabolic conditioning can certainly change how aging affects your body. As mentioned, a sedentary lifestyle could result in the loss of between 8 and 10 percent of muscle mass per decade after the age of 40; however, for those who do strength training, that loss can be as little as 2 percent per decade, which is a significant difference (McDonald 2019). The good news is that strength and power training is widely recognized as one of the most powerful means for stimulating muscle growth and can be the most effective way to limit any aging-related muscle loss (Taylor 2013; Fragala et al. 2019; Haff and Triplett 2016; Rice and Keogh 2009).