Cardiovascular Changes
Decreased cardiac reserve; reduced HR response to stress; increased arterial stiffness → isolated systolic hypertension; left ventricular hypertrophy; reduced maximum CO. SA node fibrosis → increased arrhythmia risk. Baroreceptor sensitivity decreases → orthostatic hypotension risk. Clinical implication: older adults may not mount tachycardia in response to infection or hemorrhage — assess other signs.
Respiratory Changes
Decreased lung elasticity (increased compliance) → air trapping; reduced respiratory muscle strength; decreased cough and mucociliary clearance → increased infection risk; blunted response to hypoxia and hypercapnia. Decreased PaO2 with age (expected formula: PaO2 = 104 − 0.27 × age). Clinical: increased risk for aspiration pneumonia, atelectasis; influenza and pneumococcal vaccines recommended.
Renal & Urinary Changes
GFR decreases ~1 mL/min/year after age 40 → impaired drug excretion; creatinine may appear normal despite decreased function (decreased muscle mass → less creatinine production). Bladder capacity decreases; detrusor overactivity → urinary urgency. Prostate enlargement (males) → urinary retention. Clinical: use Cockcroft-Gault to estimate CrCl for drug dosing; "start low, go slow" for renally-cleared medications.
Neurological & Sensory Changes
Decreased brain volume; slowed processing speed and reaction time; decreased short-term memory (long-term intact). Sleep: decreased total sleep, reduced REM, earlier sleep phase. Sensory: presbyopia (near vision), presbycusis (high-frequency hearing loss first), decreased taste/smell → poor appetite. Decreased pain sensitivity → atypical presentation of illness. Clinical: cognitive assessment (MMSE, MoCA); optimize lighting, hearing aids, large print; address sensory deficits.
Musculoskeletal & Integumentary
Sarcopenia: loss of muscle mass and strength — increases fall risk; resistance exercise recommended. Osteoporosis: decreased bone density — fracture risk, especially hip and vertebral. Skin: decreased collagen and elasticity → wrinkles; thinning epidermis; reduced sweat glands → heat regulation impaired; impaired wound healing. Decreased melanocyte function → photosensitivity. Clinical: fall prevention, bone density screening (DEXA), calcium/Vitamin D, moisture barriers, skin inspection.
Important Notes
- "Start low, go slow" — elderly patients require lower initial doses and slower titration for most medications.
- Fever may be blunted or absent in older adults despite serious infection — use other clinical signs.
Clinical Tips
- Use the Beers Criteria to identify medications potentially inappropriate in elderly patients (PIMs) — reduce fall, cognitive, and GI risks.
- The "SPLATT" acronym for falls: Symptoms, Previous falls, Location, Activity, Time, Trauma — comprehensive fall assessment.
Summary
Normal aging produces predictable physiological changes in every body system. Distinguishing normal aging from pathological processes enables nurses to provide safe, individualized, gerontology-informed care that maximizes function and quality of life.
