Normal Respiratory Rate, Volume, Chart, ...
Normal respiratory rate in adults is 12 breaths/min. Normal breathing, as we discussed, is strictly nasal (in and out), mainly diaphragmatic (i.e., abdominal), slow (in frequency) and imperceptible (or small/shallow in its volume).
The physiological and medical norm for respiratory minute
ventilation at rest is 6 liters per minute for a 70 kg man (see references for
textbooks below: Guyton, 1984; Ganong, 1995; Straub, 1998; Castro,
2000; etc.). These textbooks also provide the following
numbers for normal breathing:
- normal TV (tidal volume or air volume breathed in during a single breath): 500 ml;
- normal Rf (respiratory frequency or respiratory rate): 12 breaths per minute;
- inspiration: about 1.5-2 seconds;
- normal exhalation is 1.5-2 seconds, followed by an automatic pause (no breathing for 1-2 seconds).
Respiratory Rate Chart (Graph)
This graph represents the normal-breathing pattern at rest or the dynamic of the lungs' volume as a function of time. You can see that it corresponds to the normal breathing rate of 12 breaths/minute.
Warning. We cannot measure our own breathing frequency or respiratory rate since our breathing immediately changes once we pay attention to it. We breathe slower and deeper. Your result can be 2-3 times smaller than your real number during your basal-breathing pattern at rest (e.g., you will count 7 breaths/min, while your actual breathing rate is about 18-20 breaths/min). Hence, you can breathe faster than the normal respiratory rate, but your test can show that you breathe slower than the normal respiratory rate (12 breaths/min). This is a common mistake.
Other parameters of normal breathing
“If a person breath-holds after a normal exhale, it takes about 40 s before breathing commences” (McArdle et al, 2000). Hence, the normal breath-holding number (immediately after usual exhalation and after an exhale) is around 40 s. This indicates normal oxygenation of cells and tissues.
The current medical norm for CO2 pressure in the alveoli of the lungs or arterial blood is 40 mm Hg. This number was established about one century ago by famous British physiologists Charles G. Douglas and John S. Haldane (Oxford University). Their results were published in 1909 in their article "The regulation of normal breathing", Journal of Physiology (Douglas & Haldane, 1909).
What is known about other parameters of normal breathing? It is invisible (no chest or belly movements), regular, and inaudible (no panting, no wheezing, no sighing, no yawning, no sneezing, no coughing, no deep inhalations or exhalations).
Pediatric Respiratory Rate Chart
(Newborn, Toddlers, Infants, and Children)
(the source for this chart: Normal respiratory rate for children; source: health.msn.com)
|Groups and ages||Normal respiratory rates|
|Newborns to 6 months old||30-60 breaths/min|
|6 to 12 months old||24–30 breaths/min|
|1 to 5 years old||20–30 breaths/min|
|6 to 12 years old||12–20 breaths/min|
Important note. Clinical evidence suggests that respiratory rates
in healthy children are near the lower limits or even below it.
How to measure one's own breathing?
In order to define your breathing pattern, measure your body oxygenation or breath-holding time after your usual exhalation, but only until the first stress or discomfort. After doing this CP test, one can define their health state using the Buteyko Table of Health Zones.
The person with normal breathing is going to have about 40 s for the body oxygen test. In the case of chronic overbreathing, breath holding time becomes shorter (see links to Tables and studies below).
Sick people have deep and fast breathing 24/7 and reduced body oxygenation (usually about 10-20 s of oxygen in tissues). In the severely sick and critically ill patients, body oxygenation is below 10 s.
Dr. Buteyko, based on his studies of thousands of healthy and
sick people, suggested different norms for breathing (e.g., Buteyko,
1991). What are his norms? For example, his normal respiratory rate
is only 8 breaths/min. Here are his numbers for normal breathing:
- normal minute ventilation: 4 l/min;
- normal tidal volume (air volume breathed in during a single breath): 500 ml;
- normal breathing rate or frequency: 8 breaths per minute;
- inspiration: about 1.5 seconds;
- exhalation: 2 seconds;
- automatic pause (or period of no breathing after exhalation): 4 seconds;
- breath holding time (after usual exhalation and without any stress at the end of the test): 60 seconds;
- CO2 concentrations in the alveoli or arterial blood – 6.5% or about 46 mm Hg (at sea level).
Both norms (official and Buteyko's) and other related values can be found in the Buteyko Table of Health Zones.
Buteyko KP, Method of voluntary elimination of deep breathing, Buteyko method [in Russian], in Buteyko method. Its application in medical practice, ed. by K.P. Buteyko, 2nd ed., 1991, Titul, Odessa, p.148-165.
Castro M. Control of breathing. In: Physiology, Berne RM, Levy MN (eds), 4-th edition, Mosby, St. Louis, 1998.
Douglas CG, Haldane JS, The regulation of normal breathing, Journal of Physiology 1909; 38: p. 420–440.
Ganong WF, Review of medical physiology, 15-th ed., 1995, Prentice Hall Int., London.
Guyton AC, Physiology of the human body, 6-th ed., 1984, Suanders College Publ., Philadelphia.
McArdle W.D., Katch F.I., Katch V.L., Essentials of exercise physiology (2nd edition); Lippincott, Williams and Wilkins, London 2000.
Straub NC, Section V, The Respiratory System, in Physiology, eds. RM Berne & MN Levy, 4-th edition, Mosby, St. Louis, 1998.
Summary of values useful in pulmonary physiology: man. Section: Respiration and Circulation, ed. by P.L. Altman & D.S. Dittmer, 1971, Bethesda, Maryland (Federation of American Societies for Experimental Biology).
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