A distinction can be made between proximal ageing (age-based effects that come about because of factors in the recent past) and distal ageing (age-based differences that can be traced back to a cause early in person's life, such as childhood poliomyelitis).
physiologic. pertaining to physiology; normal; not pathologic. physiologic saline solution (physiologic salt solution) (physiologic sodium chloride solution) a 0.9 per cent solution of sodium chloride and water; it is isotonic, i.e., of the same osmotic pressure as blood serum. It is sometimes given intravenously to replace lost sodium and chloride.
A physiologist is a person who has received formal training in physiology, which is the study of how plants, animals, and cells function on a biological level. The field is very broad and people can choose to specialize in many different areas. As applied to humans, the field is usually really closely related to medicine.