Elderly patients develop poor endurance as a result of many factors. Aging
itself is associated with declining skeletal muscle mass and capillary blood flow,
poor nutritional intake, and impaired oxygen uptake [43]. In addition to these
factors, several common disease processes in elderly patients are shown to affect
endurance. Approximately 11% of patients older than 70 have chronic obstructive
pulmonary disease, which further decreases oxygen exchange in the lungs [44].
In addition to being a common cause of poor endurance, cardiovascular disease
(including CHF and CAD) is the second most common ailment and the leading
cause of death in older people [45]. General deconditioning from inactivity is
common in older adults and contributes to poor endurance [46]; it may predispose
to diabetes mellitus. With its associated neuropathies, pain syndromes,
and attendant risk for cardiac disease, diabetes is both a risk factor for further
inactivity and poor endurance and the sixth leading cause of death in adults
65 and older [47].