Respiratory rate is also known by respiration rate, pulmonary ventilation rate, ventilation rate, or breathing frequency is the number of breaths taken within a set amount of time, typically 60 seconds.

Respiratory rate is not yet proven whether or not this is due to age or environment and these studies have focused on such issues as the inaccuracy of respiratory rate measurement and respiratory rate as a marker for respiratory dysfunction.

Measurement

Human respiration rate is measured when a person is at rest and involves counting the number of breaths for one minute by counting how many times the chest rises. Respiration rates may increase with fever

Fever

Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, illness, OR other medical conditions. When checking respiration, it is important to also note whether a person has any difficulty breathing.

Inaccuracies in respiratory measurement have been reported in the literature. One study compared respiratory rate counted using a 90 second count period, to a full minute, and found significant differences in the rates. Another study found that rapid respiratory rates in babies, counted using a stethoscope

Stethoscope

The stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal body. It is often used to listen to lung and heart sounds. It is also used to listen to intestines and blood flow in arteries and veins...

, were 60–80% higher than those counted from beside the cot without the aid of the stethoscope. Similar results are seen with animals when they are being handled and not being handled—the invasiveness of touch apparently is enough to make significant changes in breathing.

Normal range

Average respiratory rate reported in a healthy adult at rest is usually given as 12-18 breaths per minute (V_f) but estimates do vary between sources, e.g., 12–20 breaths per minute, 10–14, between 16–18, etc. With such a slow rate, more accurate readings are obtained by counting the number of breaths over a full minute.

By Age

Average Respiratory Rates (V_f) By Age:

• Newborns: 30-40 breaths per minute
• Less Than 1 Year: 30-40 breaths per minute
• 1-3 Years: 23-35 breaths per minute
• 3-6 Years: 20-30 breaths per minute
• 6-12 Years: 18-26 breaths per minute
• 12-17 Years: 12-20 breaths per minute
• Adults Over 18: 12–20 breaths per minute.

Minute volume

Respiratory minute volume

Respiratory minute volume

Respiratory minute volume is the volume of gas inhaled or exhaled from a person's lungs in one minute. It is an important parameter in respiratory medicine due to its relationship with blood carbon dioxide levels...

 is the volume

Volume

Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....

 of air which can be inhaled

Inhalation

Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....

 (inhaled minute volume) or exhaled

Exhalation

Exhalation is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing....

 (exhaled minute volume) from a person's lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s in one minute.

Diagnostic value

The value of respiratory rate as an indicator of potential respiratory dysfunction has been investigated but findings suggest it is of limited value.

One study found that only 33% of people presenting to an emergency department with an oxygen saturation

Oxygen saturation

Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...

 below 90% had an increased respiratory rate. An evaluation of respiratory rate for the differentiation of the severity of illness in babies under 6 months found it not to be very useful. Approximately half of the babies had a respiratory rate above 50 breaths per minute, thereby questioning the value of having a "cut-off" at 50 breaths per minute as the indicator of serious respiratory illness.

It has also been reported that factors such as crying

Crying

Crying is shedding tears as a response to an emotional state in humans. The act of crying has been defined as "a complex secretomotor phenomenon characterized by the shedding of tears from the lacrimal apparatus, without any irritation of the ocular structures"...

, sleep

Sleep

Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...

ing, agitation and age have a significant influence on the respiratory rate. As a result of these and similar studies the value of respiratory rate as an indicator of serious illness is limited.