ABSTRACT
Biological causes that are age related include cardiac and pulmonary function, muscle strength, vital capacity, orthostatic changes, peripheral resistance, vital capacity, minute volume, and aerobic capacity. Psychological factors include beliefs about self, recovery, and rehabilitation in addition to delayed learning pace needing more repetitions. In the social arena, less frequent referrals to needed rehabilitative care, negative views of ageism, financial barriers, and self-ageism all impact the older adults in coping with disability and obtaining rehabilitation. The onset of aging along with the rate and extent of progression is very individualized and differs from individual to individual. Depending on the functional capacity, the biological age is the metric for the biology of aging, and not the chronological age. There are evolutionary, genetic, physiologic, and other theories of aging. The adrenal glands respond to aging with a decrease in aldosterone secretion that can explain the orthostatic hypotension experienced by aging population.
