When you go to see your doctor or other health care provider, a nurse or medical assistant will usually take your "vitals" first. The four "vital signs" are body temperature, heart rate, blood pressure and respiratory rate. These measurements give health care providers important information to help diagnose medical problems.
Temperature. In healthy adults, body temperature averages 97.8 to 99.1 degrees Fahrenheit (36.5 to 37.2 degrees Celsius) when an oral thermometer is used. Some clinics and hospitals are now using ear thermometers, which use infrared light to measure the temperature on the eardrum.
Many types of viral, bacterial and parasitic infections will raise your body temperature, which means you have a fever. Most fevers are "low-grade," meaning just a bit above normal. A "high-grade" fever means you have a body temperature of 102 degrees Fahrenheit (38.8 degrees Celsius) or higher.
A fever is the body's response to infection, and is beneficial in helping the immune system fight the infection. A fever itself is not considered dangerous until the body temperature reaches 106 degrees Fahrenheit (41 degrees Celsius) or higher.
Heart rate. Your heart rate or pulse is the measurement of how many times your heart beats in one minute. Your heart rate can be checked in several ways. The most accurate is to listen to the heart by putting a stethoscope on the chest. The most common method is to feel the pulse with the index and middle fingers placed on the radial artery, which is on the inside of the wrist, on the thumb side. The pulse can also be felt over the carotid arteries, next to the Adam's apple on the neck.
Normally, adults have a heart rate of 60-80 beats per minute, with a regular rhythm. Infants and children have faster heart rates. Smoking, caffeine and exercise all increase your heart rate and should be avoided for 30 minutes before checking the pulse. Many infections and diseases can raise your heart rate.
Blood pressure. This is the measurement of the pressure in your arteries (the blood vessels that carry blood away from your heart to the rest of your body). The typical blood pressure reading for an adult is 120 over 80 (usually written 120/80). The first number is the systolic pressure, which is the pressure when the heart is contracting. The second number, the diastolic pressure, measures pressure in the arteries when the heart is relaxed between beats.
Your blood pressure should be checked after you have been sitting down and resting for at least five minutes, since any exercise will raise the blood pressure temporarily. Your upper arm should be resting horizontally at about the level of your heart for the most accurate reading. If your arm is very large, a special large cuff should be used; a too-small cuff gives an artificially high reading.
Low blood pressure can be caused by dehydration, some medications or a heart problem. High blood pressure is most often an inherited problem, which can be modified with diet and exercise. Less commonly, it can be a sign of a kidney problem, an adrenal gland problem or the side effect of a medication.
Respiratory rate. Most adults take 12-18 breaths each minute. You breathe faster when you are frightened or in pain. Lung problems, such as asthma, pneumonia and chronic obstructive pulmonary disease (COPD) also increase the respiratory rate.
Although these vital signs provide useful information about your health, they do not give the whole picture. It's possible to have normal vital signs, yet have a serious illness. Abnormal vital signs, such as increased heart rate and blood pressure, may indicate anxiety rather than illness. Your health care provider needs to hear about your symptoms and do a physical examination before diagnosing any health problem.
Kathryn B. Brown is a family nurse practitioner with a master's degree in nursing from OHSU. Is there a health topic you would like to read about? Send ideas to firstname.lastname@example.org.