Normal Adult Vital Signs

Measuring Temperature, Breathing Rate, Pulse, and Blood Pressure

Patient consulting Doctor for breathing difficulties, Asthma
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Vital signs are measurements of the body's most basic functions—body temperature; rate of respiration (breathing); pulse rate; and blood pressure.

Doctors and other medical professionals use these measurements in numerous ways, including to assess a person's general health, to look for indications of disease, and to monitor the effectiveness of treatment for someone who is ill.

Compared to high-tech medical tests, measuring a person's vital signs is relatively simple and straightforward, requiring little more than basic medical equipment—a thermometer, stethoscope, blood pressure cuff—and a stopwatch or other timing device. The information that can be gained, however, can in some cases be a matter of life-and-death, or at least sickness and health.

Normal Vital Sign Measurements

Although factors such as age, sex, weight, and activity level can play a role in what an individual's vital signs might indicate for him or her, there is agreement across the medical community about what's normal for adults in general.

Snapshot of Normal Vital Signs in an Adult

  • Body temperature: 97.8°F to 99.1°F, with an average of 98.6°F
  • Respiration (breathing) rate: 12 to 18 breaths per minute
  • Pulse: 60 to 100 beats per minute
  • Blood pressure: 90/60 mm Hg to 120/80 mm Hg

Body Temperature

Body temperature can vary throughout the day even for a person who is healthy—typically it's lowest upon awakening and higher later in the day.

Measuring Body Temperature

Body temperature readings can vary as well, depending on the part of the body measured. An adult's temperature can be taken by mouth (oral), under the arm (axillary), or in the ear canal (tympanic) using a digital thermometer designed for these specific uses.

Glass thermometers are no longer sold in the United States because they contain mercury. If you happen to have one, do not throw it away; contact your local hazardous waste authority to find out how to dispose of it safely.

  • Oral temperature. The generally accepted average oral temperature is 98.6°F, but normal may range from 97°F to 99°F degrees. A temperature of 100.4°F most often indicates an infection or illness.
  • Axillary temperature. A normal armpit temperature is 97.6°F
  • Tympanic. Normal ear temperature readings range from 95.7°F to 100°F

The Forehead Fallacy

Laying a palm against someone's forehead may give an indication that his or her body temperature is higher than normal, but it is not a trusted method of determining illness. Neither is using forehead thermometers, which have been found to be unreliable.

Health Implications of Abnormal Body Temperature

A body temperature that is higher than normal is called a fever (pyrexia), and typically is a sign that the body is trying to fight an illness or infection by killing the virus or bacteria causing it. Fever also triggers the body's immune system.

According to MedLine Plus, other potential causes of fevers in adults include:

  • Certain medications, such as antibiotics, blood pressure medications, and anti-seizure drugs
  • Heat illness
  • Cancer
  • Autoimmune disease

A temperature reading of below 95°F can be an indication the body is losing heat more quickly than it's able to produce heat—a medical emergency known as hypothermia in which the heart, nervous system and other organs can't work normally. According to the Mayo Clinic, if left untreated, hypothermia can lead to complete failure of the heart and respiratory system and eventually to death.

Respiration Rate

Respiration rate refers to the number of breaths taken per minute while at rest. It's one of the easiest vital signs to measure, basically requiring only a clock or timer or some other way to mark the passage of 60 seconds.

Measuring Respiration Rate

To determine someone else's respiration rate, set a timer for one minute and count the number of times his or her chest rises and falls until the timer goes off.

The normal number of breaths per minute for an adult at rest is 12 to 18.

Health Implications of Abnormal Respiration Rate

A respiration rate that's slower than normal (bradypnea) or that's fast and shallow (tachypnea) are each indications of potential health problems.

Potential Causes of Abnormal Respiratory Rate
Bradypnea Tachypnea
Narcotic use (whether for medical purposes or illegally) Fever, infection
Alcohol use Dehydration
Metabolic problems Lung disease (COPD, lung cancer, asthma)
Sleep apnea Panic/anger/stress
Certain brain conditions, such as stroke or head injury Acidosis (increase in blood acidity)
  Drug overdose

Pulse (Heart Rate)

A person's pulse is created by the surge of blood through the arteries when the heart beats. Pulse rate is a measurement of how many times per minute this surge can be detected.

The normal resting pulse for a healthy adult ranges from 60 beats per minute to 100 beats per minute, although there can be variations—notably among athletes: Those who do a lot of cardiovascular training may have a resting pulse as low as 40 beats per minute because their hearts are strong enough to pump a greater-than-normal amount of blood per beat.

Measuring Pulse

A pulse can be felt most easily on the side of the neck, the inside of the wrist (the radial pulse), and the inside of the elbow—areas where arteries are located close to the surface of the skin.

To take someone's pulse at the wrist, you will need a watch with a second hand:

  • Using the tips of your first and second fingers (never your thumb), press firmly but gently on the inside of the wrist until you feel a pulse.
  • Once you've located the pulse, keep an eye on your watch; when the second-hand reaches 12, start counting each throb of pulse continuously for 60 seconds—until the second-hand reaches 12 again. Alternatively, you can count for 15 seconds and multiply the result by 4.

A person's pulse also can be taken at the neck, but it's important to not press too hard; doing so could block blood flow to the brain.

Besides counting when checking someone's pulse it's important to pay attention to how strong or weak it is and how steady, or regular, it is.

Health Implications of Abnormal Pulse

The speed, strength, and rhythm of the pulse can reveal a lot about the health of the heart as well as point to signs of diseases or conditions that may affect how the heart functions.

A slow pulse (bradycardia) can indicate:

  • A disorder of the sinus node, an area of cells in the upper right chamber of the heart that controls the rhythm of your heart. When it causes symptoms, sinus bradycardia is the most common reason to need a pacemaker, but it's rarely life-threatening.
  • Heart block, in which some or all of the electrical impulses generated by the sinus node are blocked before reaching the ventricles (the two lower chambers of the heart).

A rapid pulse (tachycardia) can indicate:

  • Any number of normal conditions in which the heart beats faster than usual, such as during exercise or stress
  • One of two types of cardiac arrhythmias: the supraventricular tachycardias, which arise in the atria of the heart, and the ventricular tachycardias, which arise in the ventricles. (Cardiac arrhythmia refers to any abnormality in the rate or rhythm of the heart.)

Blood Pressure

Each time the heart beats, blood is pumped into the arteries. Blood pressure refers to the force of blood pushing against walls of the arteries. The pressure is highest when the heart contracts (systolic pressure), and lowest when the heart relaxes (diastolic pressure).

For this reason, blood pressure readings are expressed as two numbers separated by a slash (much like a fraction). The first number refers to systolic pressure and the second number refers to diastolic pressure. These numbers are followed by the abbreviation "mm HG," which stands for millimeters of mercury. According to the American Heart Association (AHA), this is because "mercury was used in the first accurate pressure gauges and is still used in medicine today as the standard unit of measurement for pressure."

Measuring Blood Pressure

An instrument called a sphygmomanometer is used to measure blood pressure. It consists of a cuff that is placed around the upper arm and a small pump that fills the cuff with air, squeezing the arm until the circulation is cut off.

At this point, a small valve opens to allow air to slowly leak out of the cuff. As it deflates, the medical professional taking the blood pressure measurement will hold a stethoscope against the inside of the elbow to listen for the sound of blood pulsing through the arteries.

The first sound will be the systolic pressure; the second will be the diastolic pressure. A meter that's part of the sphygmomanometer indicates the specific numbers that correspond to each type of pressure.

Health Implications of Abnormal Blood Pressure

Blood pressure readings that are either higher than normal or lower than normal may indicate certain health problems.

The AHA recognizes the following categories of blood pressure readings that are higher than normal (hypertension):

  • Elevated. Readings that consistently range from 120 to 129 mm Hg systolic and less than 80 mm Hg diastolic.
  • Hypertension Stage 1. Readings that consistently range from 130 to 139 mm Hg systolic or 80 to 89 mm Hg diastolic.
  • Hypertension Stage 2. Readings that consistently are 140/90 mm Hg or higher.
  • Hypertensive crisis. A reading that suddenly exceeds 180/120 mm Hg and remains high when measured a second time after five minutes. This stage of high blood pressure requires medical attention.

When blood pressure is lower than normal (hypotension), it means the heart can no longer deliver an adequate supply of blood to the body. This can occur because of an underlying health condition such as anemia or a heart problem. Dehydration or certain medications also can cause a drop in blood pressure.

Chronically low (or even borderline low) blood pressure can have an adverse effect on the kidneys. In rare instances, a dramatic drop can lead to syncope(fainting), shock, coma, and even death.

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