Understanding Respiratory Rate and Lung Mechanics
The respiratory system is especially personal to me, because I have a respiratory disease called Asthma. This is not intended to diagnose, but to inform. See if a physician if you are concerned about your respiratory health. Respiratory Rate (RR) is the number of times you breathe per minute (1). At rest, for a healthy adult the rate is generally between 16-20 breathes per minute (2). Respiratory system holds different levels of oxygen and is never completely empty in life. Lung mechanics obey simple physics to maintain these volumes, like Boyle’s law, Law of Laplace, flow resistance and pressure gradients. I’m not explaining them here. The lungs expand through inspiration, which requires energy (ATP) because of air moving against higher pressure gradients. The lungs compress through expiration, a passive process (no ATP) moving with the pressure gradient (3). Breathing in air is against pressure gradient and expiration is the air moving from higher pressures inside to outside the lungs/ body (4). An amazing facet of the body’s ability to breathe is the movement of ribs to aid changes of thoracic pressures. The ribs move in 2 ways during inspiration to aid in thoracic expansion, like a bucket handle and pump handle (like on a well) (5). Expansion of the ribs creates a grossly visual expansion of the chest; healthily 1-3” (6). During exercise the body’s oxygen needs increase and must be met through increased ventilation. The RR increases depending on the demand of the stimulus. This increases the available arterial oxygen in contrast to its cellular use (7). RR may not have large or noticeable field improvements in athletes but is extremely important that it matches the intensity of exercise. Abnormal mechanical appearance of an athlete’s breathing rate or depth needs to be addressed immediately to ensure their safety, it is not okay to wait. Exercise is more likely show adaptations in sick persons (ex: COPD) than athletes. Benefits may be seen in increased joint kinematics and mobility.
Sources:
1.https://www.mja.com.au/journal/2008/188/11/respiratory-rate-neglected-vital-sign
2. Quantitative Human Physiology: An Introduction. Joseph Feher – Elsevier Academic Press (2017), Chap 6.2, pp. 566
3. Quantitative Human Physiology: An Introduction. Joseph Feher – Elsevier Academic Press (2017), Chap 6.2, pp. 570
4. Quantitative Human Physiology: An Introduction. Joseph Feher – Elsevier Academic Press (2017), Chap 6.2.
5. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation ed. 2nd – Mosby Elsevier – Don Neumann, Chap 11, pg 442
6. Orthopedic Physical Assessment. Magee, David J. Manske, Roberct C – Saunders (2014), Chap 8, pg 525 7. Quantitative Human Physiology: An Introduction. Joseph Feher – Elsevier Academic Press (2017), – Chap 6.4, pp. 593
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