Gerontology is the scientific study of aging, covering physical, mental, and social changes in older adults. Geriatrics focuses specifically on the medical care and treatment of diseases in the elderly. Aging is a natural biological process characterized by the gradual decline of physiological reserve across all organ systems. Cellular senescence, genetic factors, and cumulative environmental damage drive this decline. Understanding these normal baseline shifts prevents nurses from misinterpreting age-related changes as acute pathological disease.
The cardiovascular system undergoes structural stiffening with age. Arterial walls accumulate collagen and lose elastin, resulting in elevated systolic blood pressure and increased left ventricular workload. Cardiac output decreases during physical exertion because maximum heart rate declines.
In the respiratory system, chest wall compliance drops due to calcification of costal cartilage. Alveolar surface area decreases, and residual volume increases, reducing vital capacity. Gas exchange becomes less efficient, making older adults susceptible to hypoxia during minor respiratory infections.
Gastrointestinal function slows down significantly in older adults.
Renal function experiences a steady decline starting around middle age. Glomerular filtration rate drops due to nephron loss and glomerulosclerosis. Serum creatinine can remain normal despite severe renal impairment because muscle mass decreases concurrently.
Bones lose calcium and mineral density over time, increasing the risk of osteopenia and osteoporosis. Intervertebral discs dehydrate and narrow, causing a gradual loss of overall standing height. Muscle mass and strength decline through sarcopenia, altering balance and gait.
The skin thins and loses subcutaneous fat, diminishing thermal regulation and natural cushion protection. Sweat glands atrophy, reducing perspiration and raising the risk of overheating. Decreased vascularity impairs wound healing and increases pressure injury vulnerability.
Brain weight and volume decrease progressively with advanced age, accompanied by a loss of neurons and neurotransmitters. Reflexes can slow down, and cerebral blood flow diminishes slightly.
Sensory changes profoundly impact daily life:
Endocrine function shows notable shifts in glucose regulation. Pancreatic beta cells secrete adequate insulin, but peripheral tissues develop insulin resistance, raising the prevalence of type 2 diabetes. Thyroid hormone production decreases slightly, though basal metabolic rate often remains within normal limits.
The immune system undergoes immunosenescence. Thymus gland atrophy reduces the production and maturation of T-lymphocytes. Antibody responses to vaccines become less robust, and low-grade systemic inflammation increases, leaving older adults vulnerable to infections and slow recovery times.
Clinical assessment of the elderly requires adjusted techniques. Baseline vital signs must account for higher systolic pressures and lower normal core body temperatures, meaning a mild fever might present as a normal reading. Pharmacokinetics change dramatically due to reduced liver metabolism and renal clearance, necessitating lower starting drug doses to prevent toxicity. Nurses must integrate these multisystem facts to provide safe, individualized care.