If you are experiencing respiratory symptoms, you may be wondering, “what is a normal respiratory rate?” Let’s begin by talking about the normal range of respiratory rate for adults and children, how to accurately measure this rate, and what it means if the rate is abnormal.
Definition and ImportanceThe respiratory rate is defined as the number of breaths a person takes during a one-minute period of time while at rest. Recent studies suggest that an accurate recording of respiratory rate is very important in predicting serious medical events; studies also suggest that measurements of respiratory rate are not done as often as they should be, so it's been coined the “ignored vital sign.”
Measuring Respiratory RateRespiratory rate is measured by counting the number of breaths a person takes in a one-minute period. Since many factors can affect the results, understanding how to take an accurate measurement is very important.
The rate should be measured at rest, not after someone has been up and walking about. Being aware that your breaths are being counted can make the results inaccurate, as people often alter the way they breathe if they know it's being monitored. Nurses are skilled at overcoming this problem by discretely counting respirations, watching the number of times your chest rises and falls — often while pretending to take your pulse. While recording respiratory rate, several other markers of respiratory problems may also be noted. Is your patient or loved one uncomfortable? Do the muscles in her neck tighten as they breathe? (Medical professionals call this “the use of accessory muscles” to breathe.) Can you hear any wheezing or other abnormal breathing sounds?
Normal Respiratory Rate RangesIn general, children have faster respiratory rates than adults, and women breathe more often than men. The normal ranges for different age groups are listed below:
- Newborn: 30-60 breaths per minute
- Infant (1 to 12 months): 30-60 breaths per minute
- Toddler (1-2 years): 24-40 breaths per minute
- Preschooler (3-5 years): 22-34 breaths per minute
- School-age child (6-12 years): 18-30 breaths per minute
- Adolescent (13-17 years): 12-16 breaths per minute
- Adult: 12-18 breaths per minute
What Does Respiratory Rate Measure?The number of breaths we take per minute is a sign of how often the brain is telling our bodies to breathe. If the oxygen level in the blood is low, or alternately if the carbon dioxide level in the blood is high, our body is instructed to breathe more often. For example, having a severe infection increases the carbon dioxide produced in the body, so even if there's a normal level of oxygen in the blood, the brain instructs the body to breathe more often to clear the carbon dioxide.
But there are times when this system doesn’t work so well, such as when people are treated with narcotic medications. These medications in effect dull the response of the brain to signals from the blood, so someone may breathe less often than needed. This may also occur with head injuries that damage the respiratory center in the brain.
Abnormal Respiratory RatesBoth an increased and decreased respiratory rate can be a sign that something is amiss in the body. An abnormal rate is fairly nonspecific, meaning there are many causes of both a rapid and a slow rate. It’s important again to note that the normal ranges are for people at rest. Respiratory rate normally increases during exercise.
Increased Respiratory RateWhat is an elevated respiratory rate? In adults, the cut-off is usually considered a rate over 20 breaths per minute, with a rate of over 24 breaths per minute indicating a very serious condition.
As noted above, respiratory rate is a very important vital sign. One study found that in unstable patients, an elevated respiratory rate was a better determinant of who was stable vs unstable than heart rate or blood pressure.
There are many causes of an increased rate, some that are related to the lungs and some that are not. Some of the more common causes include:
- Dehydration – Dehydration alone can result in a rapid rate of breathing.
- Asthma – During an asthma attack, respiratory rate is often increased.
- COPD – Chronic obstructive pulmonary disease is a common cause of a rapid respiratory rate, especially in people with a history of smoking.
- Hyperventilation – People may breathe more rapidly in response to stress, pain, anger or during a panic attack.
- Lung conditions – Such as lung cancer, pulmonary embolism (blood clots in the legs that travel to the lungs.)
- Infections – Common and uncommon infections such as the flu, pneumonia, and tuberculosis can result in rapid breathing.
- In newborns, common causes include transient tachypnea of the newborn (TTN) — a mild condition — as well as conditions that are more serious, such as respiratory distress syndrome.
- Acidosis – An increase in the acidity of the blood results in the increased production of carbon dioxide, and hence an increased rate of breathing. This can occur when a person has a condition resulting in metabolic acidosis, such as with diabetes (diabetic ketoacidosis).
- Overdoses – Such as with an overdose of aspirin or amphetamines.
- Heart conditions – An elevated respiratory rate was found in one study to be a predictor of cardiac arrest in people hospitalized with heart conditions.
Decreased Respiratory RateA lowered respiratory rate, defined as a rate less than 12 by some, or less than 8 respirations per minute by others, can also be a sign of concern. Some causes of a decreased rate include:
- Use of narcotics – Some medications such as narcotics, whether used for medical purposes or illegally, can suppress respiration.
- Alcohol – Consumption of alcoholic beverages can decrease respiratory rate.
- Metabolic – Respiratory rate can decrease in order to balance the effects of abnormal metabolic processes in the body.
- Sleep apnea – With sleep apnea, people often have episodes of apnea and a decreased breathing rate mixed with episodes of an elevated breathing rate.
- Brain conditions – Damage to the brain, such as strokes and head injuries often result in a decreased respiratory rate.
Medical Terminology Your Doctor May UseMedical professionals use several terms to describe abnormal respiratory rates. Some of these include:
- Bradypnea – Bradypnea is the medical term used to define breathing that is abnormally slow.
- Tachypnea – Tachypnea is the medical term used to define an elevated respiratory rate.
- Dyspnea – Dyspnea refers to the sensation of shortness of breath, and can occur with an elevated, a normal, or a decreased respiratory rate.
- Hyperpnea – Hyperpnea refers to breathing that is abnormally deep and appears labored. It may occur with or without rapid breathing.
- Apnea – Apnea means literally “no breath” and refers to the absence of breathing.
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National Institute of Health. Medline Plus. Vital Signs. Updated 02/20/11. http://www.nlm.nih.gov/medlineplus/ency/article/002341.htm
Parkes, R. Rate of respiration: the forgotten vital sign. Emergency Nurse. 2011. 19(2):12-7/
University of Iowa Health Care. Pediatric Vital Signs Normal Ranges. Updated 03/21/12. https://wiki.uiowa.edu/display/protocols/Pediatric+Vital+Signs+Normal+Ranges