Normal Vital Signs for Adults

Vital signs are measurements of the body’s most basic functions—body temperature, rate of respiration (breathing), pulse rate, blood pressure, and oxygen saturation (amount of oxygen circulating in the blood). Medical professionals use these five measurements to assess one’s general health, detect and monitor medical conditions, and monitor treatment effectiveness.

Compared to high-tech medical tests, measuring a person’s vital signs is relatively simple, requiring some basic medical equipment—a thermometer, stethoscope, blood pressure cuff—and a stopwatch or other timing device. The information obtained 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.

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

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 sites 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.
• Forehead: A forehead temperature is usually lower 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 drugs
• Heat illness (e.g., heat stroke, heat exhaustion)
• Autoimmune disease
• Cancer
• Blood clots
• Some types of arthritis, such as rheumatoid arthritis and lupus

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, brain, 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.

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 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): supraventricular tachycardias, which arise in the atria of the heart, and 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) number 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 is the diastolic pressure. A meter that’s part of the sphygmomanometer indicates the specific numbers that correspond to each.

There are blood pressure monitors available for home use as well. These monitors use an arm cuff connected to a blood pressure measurement device. They are easy to use and provide accurate readings. If you want to purchase a home blood pressure monitoring device, choose one that is certified by the American Medical Association’s Validate BP list.  These devices have been validated for clinical accuracy.

How to Get an Accurate Blood Pressure Reading

Whether checking your blood pressure at a healthcare facility or measuring it at home, take these steps to get a more accurate reading:

• Don’t eat or drink for 30 minutes before taking your blood pressure.
• Empty your bladder before your reading.
• Sit in a comfortable chair with your back supported for at least five minutes before your reading.
• Put both feet flat on the ground and keep your legs uncrossed.
• Rest your arm with the cuff on a table at chest height.
• Make sure the blood pressure cuff is against your bare skin and snug, but not too tight .
• Don't talk while your blood pressure is being measured.

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):

There are hereditary and physical risk factors for high blood pressure, including:

• Sedentary lifestyle
• Obesity
• Diabetes
• Chronic kidney disease (CKD)
• Family history
• Getting older
• Gender: Men are more likely to get high blood pressure than women up to age 64. At 65 and older, women are more likely to get high blood pressure.
• Race:  Black people tend to develop high blood pressure more often than people of any other racial background in the United States.
  

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, a heart problem, or an infection. 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.

Oxygen Saturation

Oxygen saturation is the amount of oxygen in your blood. Oxygen travels through the bloodstream to the body’s organs and tissues and is critical for them to work properly,

For most healthy adults, a normal oxygen saturation level is between 95% and 100%.

Measuring Oxygen Saturation

You can check your oxygen saturation rate at home with a device called a pulse oximeter. This device uses a light source that passes through the finger and a sensor is able to calculate the oxygen in the red blood cells.

To use a pulse oximeter, you insert your finger into the device. You will feel a slight pressure, but it doesn't cause pain. Most devices beep or stop flashing when the measurement is complete.

Health Implications of Low Oxygen Saturation

There are many conditions that can cause low levels of oxygen in the blood (hypoxemia), including:

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Bronchiectasis
• Cystic fibrosis
• Interstitial lung diseases (ILDs)
• Pulmonary hypertension
• Acute respiratory distress syndrome (ARDS)
• Pulmonary embolism (a blood clot in the lung)
• A collapsed lung
• Pulmonary edema (fluid in the lung)
• High altitudes
• Medications that lower breathing rate, like some narcotics and anesthetics
• Pneumonia
• Bronchitis
• Pulmonary fibrosis (scarring in the lungs)
• Sleep apnea

Warning signs of a low oxygen level include trouble breathing, confusion, difficulty waking up, and bluish lips or face. If your oxygen saturation is less than 95%, you should talk to your healthcare provider. An oxygen saturation of 90% or less is considered a medical emergency requiring medical help right away.