Which of the following is an exception to normal physiologic changes that occur with aging?

The option referring to an increase in serum albumin is recognized as an exception to the typical physiological changes that occur with aging. As individuals age, there is generally a decrease in the production of serum proteins, including albumin, which can lead to lower levels of serum albumin in the bloodstream. This decrease is associated with various age-related physiological changes such as diminished liver function and changes in body composition.

In contrast, the other options listed represent normal physiological changes commonly observed in aging individuals. A decrease in muscle mass, for example, is a widely acknowledged occurrence known as sarcopenia, where muscle tissue diminishes over time, impacting strength and mobility. A decrease in total body water also typically occurs, as older adults generally have a lower percentage of water in their bodies due to changes in body composition and renal function. Furthermore, an increase in gastric pH is common due to a reduction in gastric acid production, which can affect digestion and nutrient absorption.

Therefore, the assertion that serum albumin increases with age distinctly deviates from the expected physiological trends, making it the correct answer in identifying an exception to the normal changes associated with aging.