Normal Physiologic Changes With Aging

An anxious 80-year-old woman presents with multiple complaints. You perform a thorough evaluation of this patient, including laboratory work, stress testing with echocardiography, and pulmonary function testing. When evaluating this woman and her test results, which of the following is considered a normal finding for her age?

A. Decrease in creatinine clearance
B. Blood pressure of 160/80
C. Elevated FEV1 value on pulmonary function tests
D. Low-frequency hearing loss
E. Maximum stress test heart rate of 90

Answer : A. Decrease in creatinine clearance

Discussion: There are many changes that occur normally as a result of aging. There is a decline in renal perfusion and functional glomerular units that results in a decline in creatinine clearance. This may clinically manifest as an increased susceptibility to medication side effects or toxicity. 

Definitions of hypertension do not change with age, and an elderly person with a blood pressure of 160/80 would be considered hypertensive. 

There is a decrease in FEV1 that occurs naturally as part of aging that is similar in effect but to a much lesser degree than occurs with smoking. 

High-frequency hearing loss is considered a normal finding in the elderly and may represent age-related cumulative high-frequency injuries to the hearing apparatus. 

The minimal acceptable heart rate response to stress testing is adjusted for age by the following formula: maximum heart rate = (220 - age) × 0.85. Thus, in this patient, a heart rate response increasing to 119 beats per minute would be considered adequate for interpreting the stress test results

NORMAL PHYSIOLOGIC CHANGES WITH AGING: 

CNS/sensory

Presbyopia

Presbycusis

Slowed reaction times

Alteration in sleep efficiency

Gastrointestinal

Decreased number of taste buds

Slowed intestinal motility

Metabolism

Decreased hepatic blood flow

Decreased renal blood flow

Decreased creatinine clearance

Body composition

Increase in percentage body fat

Decrease in percentage body water

Decrease in muscle mass

Cardiovascular

Blood pressure tends to increase

Heart rate responses blunted

Left ventricular stiffness

Relative decrease in cardiac output with exercise

Pulmonary

Decrease in FEV1 and pO2

Diminished cough reflex

Electrolytes/water balance

Decrease basal and stress-induced increase renin and aldosterone

Increased basal vasopressin

Decrease in ability to concentrate urine

Decrease thirst response to hyperosmolarity

Decrease in total body potassium