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 Vital Signs


                     Vital signs are important measurements that indicate a                           person’s state of health.  They help to give a quick overview of basic body functions. Abnormal measurements can be a symptom of a disease or illness in the body.  Paying close attention to a patient’s vital signs can sometimes be a good clue to diagnosing a health problem.


   Keep in mind when reading the descriptions below that vital signs can vary with age, gender, weight, physical fitness, or disease conditions. Normal measurements will be slightly different for you when compared to your parents.

Learning Objectives

By the end of this lesson, students should be able to:

  • Explain the importance of vital sign measurements as indicators of health.

  • List four body measurements are that considered vital signs.

  • Describe the four main vital signs and how they are measured.


blood pressure—the force exerted on the inside of the artery walls by blood pumped by the heart.

brachial artery—the artery in the upper arm near the elbow.


bradycardia—a slow pulse rate.

diastolic pressure— the pressure of blood against the inside artery walls when the heart is at rest.

hypertension—high blood pressure.

hypotension—low blood pressure.

pulse oximeter—an instrument used to measure oxygen levels in the blood.

pulse rate— the number of times the heart beats per minute.

radial artery—the artery in the wrist used most often to take a pulse measurement.

respiration rate—the number of breaths per minute.

stethoscope—a medical instrument used to magnify sounds coming from inside the body.

systolic pressure— the pressure of blood against the inside of artery walls when the heart contracts.

tachycardia—a rapid heart rate.

temperature—a measure of heat in a living body.


Determining Vital Signs

   The four measurements that are generally considered to be vital signs are:

1) Body temperature 
  Normal body temperature varies with gender, activity, and time of day and can range from  97.8° F (Fahrenheit) to 99° F (or 36.5° to 37.2° Celsius).

To measure body temperature:

   Temperatures can be measured orally,

rectally, axially (at the armpit) or in the ear.  

Temperatures can also be measured using

an infrared, contactless thermometer by

scanning the forehead.


   Temperatures taken rectally are usually 0.5—0.7° F higher than temperatures taken by mouth. Temperatures taken axially are generally 0.3—0.4° F  lower than temperature taken by mouth.


   An elevated temperature usually indicates a possible infection.













2) Pulse
  Pulse is produced as the heart pushes blood through arteries.  Arteries have thick, muscular walls which can contract and help push the blood though the body and away from the heart.


   The pulse rate is the number of times the heart beats per minute. Taking a pulse rate measures not only the beats per minute, but also shows if the heart has a normal rhythm or if the pulse is strong or weak.


The normal pulse rate for adults is 60—100 beats per minute. Pulse rates vary with age, exercise, illness, injuries, emotions, or stress.


To measure pulse rates:

   Pulse rates are usually measured using the radial (at the wrist) artery.


• Find the radial artery located on the

ventral (the underside) area of your wrist,

down from your thumb, as shown in the

picture to the right.

You may need to move your fingers up or

down the wrist area to find the pulse.

• Place your index finger and middle finger over the artery and count the beats for 30 seconds and multiply by 2.  This will give the beats per minute.  You can also count for 15 seconds and multiply by 4, but this is not as accurate. Do not use your thumb to take a pulse measurement because the thumb also has a pulse and this will give inaccurate readings.

   For example, a measurement of 40 beats in 30 seconds would mean a pulse rate of   40  X   2   =   80 beats per minute.

   A measurement of 15 beats in 15 seconds would mean a pulse rate of
15  X  4  =  60 beats per minute.

• If the rate is very slow or very fast, count for the full 60 seconds to obtain an accurate measurement.

• At the same time, note the regularity of the beats.  The heartbeat should be very regular, but some irregularities are common and do not represent any serious health issue. Completely irregular rhythms and extra beats should be investigated in more detail.

   If you cannot find the radial pulse, a pulse rate can be taken over the carotid artery (one on each side of your neck).  Do not push too hard on the carotid artery, as this artery carries oxygenated blood to the brain; a light touch is all that is needed.

      A fast pulse (tachycardia) could indicate fever, anemia (too few blood cells), dehydration, drugs, such as caffeine, nicotine, or cocaine, a variety of heart conditions, or just excitement or anxiety.


   A slow pulse (bradycardia) could be caused by medications such as some high blood pressure drugs or a variety of heart conditions.  Athletes may also have slow heart rates because their improved physical condition makes their hearts more efficient at slower rates.



3)  Blood pressure
  Blood pressure is the force exerted on the 
inside of the artery walls by blood pumped by the heart. You measure blood pressure over arteries and not over veins because the thicker, muscular walls of arteries help to push blood through the circulatory system as it moves away from the heart.  Veins carrying blood returning to the heart are thin-walled, and do not pulse.
To measure blood pressure:
  Blood pressure is measured with a

blood pressure cuff, or

sphygmomanometer, and a stethoscope.

There are many electronic blood

pressure cuffs with digital readouts that

accurately measure blood pressure.

These are much easier to use than the

traditional blood pressure cuffs with dials or columns of numbers, but they may not always be accurate enough. 

                                        Image: Location of the brachial artery most often used to measure blood pressure.                                 

• Place the cuff on the person’s arm with the monitor over the brachial artery (on the side of the upper arm nearer to the body and by the elbow.) 

• Place the stethoscope under the cuff and over the artery.

• Watching the dial or column, inflate the cuff until the needle is OVER 200. Inflating to just over 200 is usually enough for every patient. If you know the patient is likely to have low blood pressure, you would not have to inflate the cuff as much.

• Slowly, let out a steady stream of air from the cuff as you watch the dial or the column of fluid move over the numbers.

•  You are looking for the FIRST number at which you hear the FIRST heartbeat and the LAST number at which you hear the LAST heartbeat.

The higher number is the systolic pressure, or the pressure of blood against the inside of the arterial walls when the heart contracts.


   The lower number is the diastolic pressure, or the pressure of blood against the inside of the arterial walls when the heart is at rest.

Normal blood pressure is less than 120 / 80. (But, remember that normal readings vary with age, gender, or physical fitness.


   High blood pressure (hypertension) can be caused by the narrowing of arteries due to fat deposits or a fast heartbeat.  A variety of heart conditions can also cause high blood pressure, as can some medications, but often the reason is not known.  There is a strong genetic link to having high blood pressure. 

  High blood pressure cannot usually be cured, but it can be treated and controlled. It is important to monitor and receive treatment for        high blood pressure.  Hypertension increases the risk of coronary heart disease, stroke, kidney disease, and blindness.  Untreated high blood pressure can result in irreversible heart damage.

Blood pressure is considered high if the reading is 140 or higher / 90 or higher.

   Low blood pressure (hypotension) can be caused by pregnancy, medications, heart problems (low pulse rate, heart valve problems, heart attack and heart failure), diabetes, thyroid gland problems, dehydration, blood loss from injury, severe infection, or severe allergic reactions. 

  Blood pressure is considered low if it is lower than 90 / 60.  It is usually much more difficult to diagnose low blood pressure than high blood pressure because what is low for one person may be normal for another. Health care practitioners usually consider the absence or presence of symptoms before confirming a low blood pressure diagnosis.


4) Respiration Rate
The respiration rate is the number of breaths in one minute.


How to measure respiration rates
  Respiratory rates are measured by counting the number of times the patient’s chest rises in one minute or in 30 seconds and multiplied by 2. Patients are usually not aware of the procedure because it may be possible for them to control the breaths taken. It is usually done when the pulse is taken because the health practitioner is already timing heartbeats per minute.  It is an easy jump to watch the number of times the chest rises.

   The regularity of the breaths is also noted, along with the type of breaths taken (shallow, deep, wheezy, or painful, for example).


   The normal respiration rate is 15—20 breaths per minute.


   Some medical personnel say that respiration rates are not good indicators of disease, except possibly, with the exception of some heart disease conditions.

   There is also a “fifth vital sign” that is sometimes used to assess a person’s health condition.  Patients rate their discomfort on a scale of 0—10.  Other medical personnel say that pain is not a vital sign because each patient has a different tolerance to pain. What is painful to one patient may not seem as painful to another.

   Still others use blood oxygen levels

as the fifth vital sign. A pulse oximeter

is used to measure how much oxygen

is in the blood. A sensor is attached

to the finger which is attached to a

monitor which displays the percent

oxygen in the blood.

                                                              Image: A pulse oximeter measuring percent oxygen in the  blood.                                                          


Check Your Understanding

1. What are vital signs and why are they important measurements?


2. Describe the four main vital signs and how they are measured.

© Wheeling University, 2023. All rights reserved.




a thermometer on a table
a person taking a pulse with two fingers on the radial artery of another person
one person taking another person's blood pressure using a cuff and stethoscope
a wrist with a digital oximeter instrument with the meter on the index finger of the hand

Fast Fact: How Do No-contact Thermometers Work?

   You have probably had your temperature taken with a no-contact thermometer. These thermometers are thermal imaging thermometers. A camera in the device captures heat emitted by your body. Hotter objects look brighter to a thermal camera. (Regular cameras capture light, not heat.) Sensitive cameras can be accurate to 0.1 0 F. If a higher temperature is measured, doctors can look for a health problem that might cause it. During the covid-19 pandemic, medical personnel use contactless thermal imagining thermometer to scan people’s forehead to measure their temperature.

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