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 can, in some cases, be a matter of life and death, or at least sickness and health.
Although factors such as age, sex, weight, and activity level can play a role in what an individual’s vital signs might indicate, there is agreement across the medical community about what’s normal for adults in general.
Measuring Body Temperature
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.
The readings can vary depending on which one of these is used.
Oral: The generally accepted average oral temperature is 98. 6 F, but normal may range from 97 F to 99 F. A temperature of 100. 4 F most often indicates an infection or illness. Axillary: An armpit temperature is usually lower than the oral temperature by half to one degree. Tympanic: An ear temperature is usually higher than the oral temperature by half to one degree.
Health Implications of Abnormal Body Temperature
A body temperature that is higher than normal is called a fever (pyrexia) and is typically 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.
Other potential causes of fever in adults include:
Certain medications, such as antibiotics, blood pressure medications, and anti-seizure drugsHeat illness (e. g. , heat stroke, heat exhaustion)Autoimmune diseaseCancer
A temperature reading below 95 F can be an indication the body is losing heat more quickly than it is able to produce it—a medical emergency known as hypothermia in which the heart, nervous system, and other organs can’t work normally.
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, as you only need a clock or timer.
Measuring Respiration Rate
To determine your respiration rate, set a timer for one minute and count the number of times your chest rises and falls until the timer goes off. It may be helpful to enlist a loved one or care provider to help you measure your respiration, as observing your own breath may cause you to breathe more slowly than you naturally would, leading to an inaccurate result.
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) is an indication of potential health problems.
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 your 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 your 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 (pulse) continuously for 60 seconds (until the second hand reaches 12 again). Alternatively, you can count for 15 seconds and multiply the result by four.
Health Implications of Abnormal Pulse
Besides counting when checking someone’s pulse, it’s important to pay attention to how strong or weak the pulse is and how steady, or regular, it is. 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 its rhythm): 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 (abnormalities in the rate or rhythm of the heart): The supraventricular tachycardias, which arise in the atria of the heart, and the ventricular tachycardias, which arise in the ventricles
Blood Pressure
Blood pressure refers to the force of blood pushing against the walls of the arteries every time the heart beats. Blood pressure readings contain two numbers (e.g., 120/80 millimeters of mercury, or mmHg):
The first (top) is the systolic pressure. This is the highest number, as it is the pressure when the heart contracts. The second (bottom) number is the diastolic pressure. This is the lowest number, as this is the pressure when the heart relaxes.
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 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.
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 American Heart Association recognizes the following categories of blood pressure readings that are higher than normal (hypertension):
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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