Influence of age and physical training on postural adaptation.
Movement from the supine to the upright position brings about the transfer of blood from the upper to the lower body. Cardiac output and central arterial pressures are reduced causing, in the normal subject, a reflex increase in sympathetic and a decrease in parasympathetic activity. Increased sympathetic activity facilitates cardiovascular and skeletal muscular adjustments aimed at maintaining cerebral blood flow. If there were no compensatory cardiovascular changes, the reduced cardiac output due to the pooling of blood into the dependent regions of the body would result in cerebral ischemia and loss of consciousness (postural hypotension). This situation is most often experienced in the elderly population and can have quite a debilitating influence on daily living activities. It is known that as humans age, the efficiency of bodily functions often becomes impaired. It is also known that exercise can improve the function of the cardiovascular system as shown by an improved work capacity and lowered incidence of heart disease and high blood pressure. These exercise-related changes suggest that exercise may have implications in the management of postural hypotension. However, recent studies have given conflicting accounts regarding the relationship between regular exercise and postural adaptation, with some studies describing an impaired adaptation in athletes. The purpose of this paper is to summarize, in detail, the influences of age and physical fitness on postural adaptation.
Petrella
R J
RJ
Faculty of Physical Education, University of Western Ontario, London.
Cunningham
D A
DA
Smith
J J
JJ
D000222:Adaptation, Physiological; D000368:Aged; D000375:Aging / Q000502:physiology*; D001775:Blood Circulation; D001794:Blood Pressure; D001808:Blood Vessels / Q000503:physiopathology; D006321:Heart / Q000503:physiopathology; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology; D010809:Physical Fitness; D011187:Posture