CARDIOVASCULAR AND PULMONARY ISSUES RELATED TO REHABILITATION OF THE GERIATRIC PATIENT
William H. Staples, PT, DHSc, DPT, GCS, CEEAA
The aging cardiopulmonary and respiratory systems are important to understand in relation to rehabilitation. Understanding the normal cardiovascular and pulmonary changes can assist therapists when judging the functional capacities of aging adults either with or without other comorbidities.
There are minimal changes in resting heart rate, plasma volume, or hematocrit readings as people age normally without pathology. Several decreases occur, however. There is an overall reduction in distensibility, contractility, and elasticity. The decreases include loss of maximal aerobic capacity, maximal heart rate, maximal cardiac output, stroke volume, peak heart rate, maximum O2 consumption, endothelial reactivity, maximal skeletal muscle blood flow, capillary density, vascular insulin sensitivity, heart size, end-diastolic filling, compliance of large arteries, and secretion and release of catecholamines. A decrease in pacemaker cells in the S-A node can lead to slightly slower heart rate, and tonic modulation of the cardiac period. Decreased sensitivity of the baroreceptors can lead to postural hypotension in response to stress. There is diminished speed of red blood cell production in response to stress of illness, along with decreased levels of HDL (good) cholesterol, and lipoprotein lipase activity, which may then promote obesity and atherosclerosis. 1-3
There are increases in the cardiovascular function as well, but increases are not necessarily a good thing. There is an increase in fat (noncontractile) and fibrous (nondistensible) tissue. The left ventricular mass and wall thickness amount of blood the chamber can hold may actually decrease, leading to heart filling more slowly. There is thickening of valvular structures and addition to the epicardial fat. Heart rate and blood pressure response to submaximal exercise increase as do peripheral vascular resistance, total cholesterol, and LDL (bad) cholesterol. 1-3
The functional implications of these cardiovascular changes is significant and leads to lower HRmax, lower stroke volume and cardiac output, and increased blood pressure. An increased threat of cardiovascular disease may lead to premature death and/or function. A reduced blood flow and therefore reduced oxygen to the skeletal muscles will also limit function as we age. Decreased VO2 max and reduced skeletal muscle oxidative capacity will lead to reduced exercise capacity and blunted exercise response that will also limit function. 1-3
Pulmonary changes as we age will also affect us as we age. There is little to no change in total lung capacity, but there are many decreases. Decreases include vital capacity, tidal volume, vascular insulin sensitivity, maximal air flow rates, respiratory muscle strength, lung expansion, and elastic recoil. Decreases also accompany the aging process and including loss of alveolar surface area, up to 20%, which leads to decrease in maximum O2 uptake. Alveolar vascularity and the number of cilia/function also decrease. Alveoli tend to collapse sooner on expiration due ...