Vital Signs: Overview and Effect of Aging Changes
National Library of Medicine
Vital signs show an individual is alive. They include heart beat, breathing rate, temperature, and blood pressure. These signs may be watched, measured, and monitored to check an individual’s level of physical functioning. Normal vital signs change with age, sex, weight, exercise tolerance, and condition.
Normal ranges for the average healthy adult vital signs are:
Temperature: 97.8 – 99.1 degrees Fahrenheit / average 98.6 degrees Fahrenheit
Breathing: 12 – 18 breaths per minute
Pulse: 60 – 80 beats per minute (at rest)
- Systolic: less than 120 mm of mercury (mm Hg)
- Diastolic: less than 80 mm Hg
Normal body temperature does not change significantly with aging. Temperature regulation, however, is more difficult.
Because of changes in the heart, the resting heart rate may become slightly slower. It takes longer for the pulse to speed up when exercising, and longer to slow back down after exercise. The maximum heart rate reached with exercise is lowered.
Blood vessels become less elastic. The average blood pressure increases from 120/70 mm Hg to about 150/90 mm Hg and may remain slightly high even if treated. The blood vessels also respond more slowly to a change in body position.
Although lung function decreases slightly, changes are usually only in the reserve function. The rate of breathing usually does not change.
Effect of Changes
Loss of subcutaneous fat makes it harder to maintain body heat. Many older people find that they need to wear layers of clothing in order to feel warm. Likewise, skin changes include the reduced ability to sweat. Therefore, older people find it more difficult to tell when they are becoming overheated.
There may be decreased tolerance to exercise. Some elderly people have a reduced response to decreased oxygen or increased carbon dioxide levels (the rate and depth of breathing does not increase as it should).
Many older people find that they become dizzy if they stand up too suddenly. This is caused by a drop in blood pressure when they stand called orthostatic hypotension.
Medications that are used to treat common disorders in the elderly may also have a profound effect on the vital signs.
For example, digitalis (used for heart failure) and certain blood pressure medications called beta blockers may cause the pulse to slow. Pain medications can slow breathing. Diuretics can cause low blood pressure and aggravate orthostatic hypotension (a drop in blood pressure when changing body position).
Older people are at greater risk for overheating (hyperthermia or heat stroke). They are also at risk for dangerous drops in body temperature (hypothermia).
Fever is an important sign of illness in the elderly. Many times, fever is the only symptom for several days. Any fever that is not explained by a known illness should be investigated by a health care provider.
Often, older people are unable to create a higher temperature with infection so very low temperatures and checking the other vital signs plays an important role in following these people for signs of infection.
Heart rate and rhythm problems are fairly common in the elderly. Excessively slow pulse (bradycardia) and arrhythmias such as atrial fibrillation are common.
High blood pressure (hypertension) and a drop in blood pressure when changing body position (orthostatic hypotension) are common blood pressure problems. High blood pressure should always be discussed with your health care provider.
Breathing problems are seldom normal. Although exercise tolerance may decrease slightly, even a very elderly person should be able to breathe without effort under usual circumstances.