AGING AND FLUID AND pH REGULATION
Changes in fluid balance or pH in elderly people are often the result of disease or damage to particular organs. A weak heart (congestive heart failure) that cannot pump efficiently allows blood to back up in cir-culation. In turn, this may cause edema, an abnormal collection of fluid. Edema may be systemic (often apparent in the lower legs) if the right ventricle is weak, or pulmonary if the left ventricle is failing.
The sense of thirst may not be as acute in elderly people, who may become severely dehydrated before they begin to feel thirsty. An important behavioral consideration is that elderly people who fear urinary incontinence may decrease their intake of fluids.
Deficiencies of minerals in elderly people may be the result of poor nutrition or a side effect of some medications, especially those for hypertension that increase urinary output. Disturbances in pH may be caused by chronic pulmonary disease, diabetes, or kidney disease.