What you’ll learn to do: explain the physiological changes during middle adulthood and their physical and psychological consequences
Hippocrates (author of the famous “Hippocratic oath”) was of the opinion that “walking is the best medicine.” This was his learned opinion in 400 BCE and there is now considerable, and increasing, evidence that he may have been correct.
As we will see, there are simple physiological changes that accompany middle adulthood. These are somewhat inevitable, but the importance of physical activity at this age range would be difficult to overstate looking at the evidence. Exercise does not necessarily mean running marathons, it may simply mean a commitment to using your legs in a brisk fashion for thirty minutes. “Use it or lose it” is a good mantra for this stage of development—the technical term for the the loss of muscle tissue and function as we age is sarcopenia. From age 30, the body loses 3-8% of its muscle mass per decade, and this accelerates after the age of 60 (Volpi et al, 2010). Diet and exercise can ameliorate both the extent and lifestyle consequences of these kinds of processes. In this section, we will examine some of the changes associated with middle adulthood and consider how they impact human life. 
- Volpi, E., Nazemi, R., & Fujita, S. (2004). Muscle tissue changes with aging. Current opinion in clinical nutrition and metabolic care, 7(4), 405-10. ↵