The 5 Main Vital Signs and What They Say About Your Health
Key takeaways:
Vital signs are five measurements that provide a quick picture of whether you are healthy or sick. Changes to your vital signs can sometimes be a clue that something is amiss.
Each vital sign has a normal range. There is natural variation within that range based on factors like age and other medical conditions.
Regular assessment of your vital signs can detect sudden illnesses, as well as chronic conditions you may not know you have.
Whenever you see a healthcare provider, someone probably checks your vital signs at the beginning of your visit. This includes temperature, heart rate, blood pressure, breathing rate, and your oxygen saturation. These numbers can change based on your age, weight, and health. They can even change based on your current emotional state.
Healthcare providers use vital signs to screen for any change in your current health status. This can be to screen for chronic conditions — like high blood pressure. Or a sudden illness — like an infection. In other words, your vital signs can be a clue to what’s going on beneath the surface. Let’s take a closer look at what each of these numbers mean, and how they change.
1. Temperature
Most people have heard that a normal body temperature is 98.6°F. But the range of normal is 97.8°F to 99.1°F
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How it’s measured
There are a few different ways to measure your temperature. In the past, people used a glass thermometer in the mouth or rectum to tell temperature. Now, most people use digital thermometers. These can measure a temperature from the:
Forehead
Mouth
Eardrum (also called the tympanic membrane)
Rectum
Of all these different types, tympanic thermometers seem to be the most accurate.
What causes a high temperature
Your body temperature may increase because of several conditions, including:
Infection: A fever from a virus or bacteria is the most common reason someone’s temperature rises.
Inflammation: A high temperature can be a sign of inflammation but not infection. This happens with autoimmune diseases (like lupus or rheumatoid arthritis).
Heat illness: Heat exhaustion and heat stroke can increase your temperature. This can happen from physical exertion in warmer temperatures or just being in a warm environment for a prolonged period of time.
Medications: Your risk for heat illness can increase with some medications (like psychiatric medications or even Benadryl).
Cancer: Some cancers or tumors can cause your body temperature to run higher than normal. But this is less common.
What causes a low temperature
While abnormal temperatures are not often thought of as being too high, you can also have body temperatures that are too low. Hypothermia (low body temperature) can be seen in the following conditions:
Cold exposure: Hypothermia doesn’t just happen when you are outside in the extreme cold. It can happen in a more gradual way, even inside at temperatures from 60°F to 65°F.
Malnourishment: Without proper nutrition, the body does not have the energy to keep itself warm.
Hypothyroidism: If you do not have enough thyroid hormone, everything in your body slows down. This can loweryour body temperature.
Sepsis: This occurs when the body becomes overwhelmed by a serious infection. And many times it lowers — rather than elevates — someone’s temperature.
Signs vs. symptoms: The words “signs” and “symptoms” are often used interchangeably, but they have distinct meanings. Learn more about the difference and how your doctor might use these terms.
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2. Heart rate
For adults, a normal heart rate is 60 to 100 beats per minute. For children, normal heart rates vary depending on age. Babies and younger children have faster heart rates. As they grow older, their heart rates become closer to adult ranges.
How it’s measured
You can check your heart rate by feeling your pulse on your wrist or neck. When you are in a clinic or hospital, other tools can measure your heart rate. An oxygen monitor can usually also calculate your heart rate. Or if you are on a heart monitor (telemetry), this also measures the way your heart is beating.
What causes a high heart rate
There are many reasons your heart can beat faster. Some examples include:
Exercise or exertion
Dehydration
Stress
Sugar, caffeine, or alcohol intake
Low blood counts
Hyperthyroidism
Infection
Pregnancy
Heart problems (like atrial fibrillation)
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What causes a low heart rate
You might have a lower than normal heart rate if you:
Have a high level of physical fitness
Are extremely relaxed
Take certain medications (like beta blockers)
Have a heart arrhythmia (like heart block)
Have severe electrolyte imbalances (like high potassium levels)
3. Blood pressure
Your blood pressure measures the pressure inside your blood vessels. It consists of two different measurements, including:
The first (top) number (systolic pressure) measures the pressure in your blood vessels when your heart squeezes blood to the body.
The second (lower) number (diastolic pressure) measures the pressure in your blood vessels between each time your heart beats.
A normal blood pressure is anything less than 120/80 and greater than 90/60.
How it’s measured
To measure your blood pressure, a cuff is placed on your arm. The cuff is then inflated. A provider will inflate a cuff around your arm. With a stethoscope, they listen to the blood flowing through your arm.
But you can also measure your blood pressure on your own. An electronic blood pressure machine can inflate and take these measures for you. These types of machines are often available at pharmacies and grocery stores.
What causes a high blood pressure
There are many things, including emotional and physical stressors, that can elevate your blood pressure. Even a healthcare visit itself can raise your blood pressure. This is known as “white coat hypertension.” It occurs when the stress of being evaluated by medical professionals raises your blood pressure.
It is normal to have variations in your blood pressure. But if your blood pressure regularly runs more than 130/90, this may mean you have hypertension or high blood pressure.
Other things that can cause high blood pressure include:
Diabetes
Kidney disease
Certain medications
Caffeine, tobacco, alcohol, and substance use
Genetic factors, like ethnicity and family history
What causes a low blood pressure
Many people worry about their blood pressure being too high. But low blood pressure can also be a problem. Sometimes, low blood pressure is normal. This is true for people who have good cardiovascular fitness, like athletes. Their hearts will beat very efficiently.
For others, low blood pressure can be a sign of something more serious. Conditions that can cause low blood pressure include:
Heart arrhythmias
Heart failure
Blood loss
Dehydration or malnutrition
Severe infection (like when someone has sepsis)
Medications (like ones intended to make you relaxed or even drowsy)
High doses of high blood pressure medications
4. Breathing (respiratory) rate
A normal breathing or respiratory rate for adults is 12 to 20 breaths per minute. Like heart rate, respiratory rates for children depend on age. A normal rate for infants can be as high as 60 breaths per minute.
How it’s measured
This vital sign is not always measured along with your other vital signs. Providers usually measure this when there is a specific concern about your breathing. It can be measured by simply counting your breaths over the course of a minute.
What causes a fast breathing rate
A fast respiratory rate can often be a sign of a problem with the lungs. This can include:
Infection anywhere in the body, not just the lungs
Bronchitis
Asthma flare
A pneumothorax or “collapsed lung”
Fluid in the lungs
Diabetic ketoacidosis
Sepsis
Panic or anxiety
What causes a slow breathing rate
When someone is breathing slowly, it is usually because something is affecting their level of consciousness. This means that it’s usually a problem with the brain and not with the lungs. This can include thing like:
Medications that cause drowsiness
Drug and alcohol use
Brain injury
Stroke
Sleep apnea, when it occurs during sleep
5. Oxygen saturation
Oxygen saturation measures the percentage of your blood that has oxygen bound to it. A normal oxygen saturation is less than or equal to 95%.
How it’s measured
A pulse oximeter can measure your oxygen saturation. This is often a clip or sticker with a red LED light placed over your finger. Depending on how that light is absorbed, the sensor will read how much of your blood is bound to oxygen.
What causes a low oxygen saturation
The oxygen saturation can be low for a wide range of reasons. Many of them are like the things that can cause a high breathing rate above:
Pneumonia
Fluid in the lungs
Asthma or COPD (chronic obstructive pulmonary disease)
A pneumothorax or “collapsed lung”
Medications that makes you drowsy or slows down your breathing
Other intoxications or poisonings (like carbon monoxide)
The bottom line
Vital signs are a routine part of most healthcare encounters. They show how your body is working. And vital signs can often offer important clues when your body may not be at its best. When you don’t feel good and aren't sure what’s wrong, vital signs are a great start to figuring out the cause. You can measure your own vital signs at home. But if they are out of your normal range, see your healthcare provider right away.
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References
Berg, M. D., et al. (2010). Part 13: Pediatric basic life support. 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation.
Centers for Disease Control and Prevention. (2021). High blood pressure symptoms and causes.
Del Bene, V. E. (1990). Chapter 218: Temperature. Clinical methods: The History, Physical, and Laboratory Examinations. 3rd Edition.
Hafen, B. B., et al. (2022). Oxygen saturation. StatPearls.
Mah, A. J., et al. (2021). Studying the accuracy and function of different thermometry techniques for measuring body temperature. Biology.
MedlinePlus. (2021). Vital signs.
National Health Service. (2023). Low blood pressure (hypotension). NHSinform.
National Heart, Lung, and Blood Institute. (2022). Low blood pressure.
Sapra, A., et al. (2022). Vital sign assessment. StatPearls.
