Use of Lung Capacity

Our lungs have enough capacity (see) for us to breathe in 4.8 litres of air in one breathe and exhale the same out. For using the full capacity of the lungs, we need to breathe really deep using all the muscles that can control our breathing. It can be done but this practice will be called an breathing exercise rather than simply breathing. Breathing exercise should be indulged in to keep the lungs and the related muscles in shape just like we exercise the body and various muscles to keep them in shape.

Breath  goes on atonomously 24/7 without involving our attention or engaging us in breathing exercises same body body keeps working 24/7 autonomously without involving us in physical exercises. Breathing tha happens 24/7 to keep the body working is autonomous in nature. The frequency of automous breathing varies from person to person and from time to time and is estimated to be on the average between 8 and 20 breaths per minute.

Why does autonomic breathing rate vary from person to person? Our genes configure every person to handles our survival emotions differently. Perceeption of the degree of satisfaction of our deemed survival needs is varies from individualto individual. It is this perception that keeps us activity oriented to varying amounts. The extent of activity orientation (see) is expressed in activity readiness with the activation of sympathetic divison of the autonomic nervous system. Sympathetic dominance simply becomes human nature although each individual human being has different degrees of it. The frequency of our autonomic braething is realted with the degree of our activity dispensation expressed in symapthetic dominance, the higher the sympathetic dominance, the higher the rate of breathing.

Why does the frequency of breathing in the same person change from time to time. That again depends upon the person's emotional state which chages from time totime. There  is a general level of symathetic dominance depending upon our gene expression and there is a momentary level of it depending upon how we feel at any given time. When we feel excited, angry, depressed or anxious, our sympathetic dominance is higher and so is our breath frequency.

Breathe frequency determines the amount of air we autonomously inhale and exhale per breath, the higher the breath frequency, the lower the volume of ait inhaled and exhaled per breath. Table below is a reproduction of ‘Table 11-5’ from a book entitled Human Physiology (Sherwood Lauralee, Kell Robert, and Ward Christopher. 2013. Human Physiology. Nelson Education, page 470). The range of breath frequencies at rest in this table are within the autonomic breathing range except that of 40 br/min which is included to dramatically highlight the effect of dead space in reducing alveolar volume with increasing frequency. This table is typical of empirical data available from scientific literature on human physiology.

The table shows that the total tidal volume V_t ​of air breathed in per minute at rest stays the same at 6 litres.The volume of air in the alveolar sacks V_a​ varies because of effect of dead space in the upper reaches of the lungs and the trachea; the air in the dead space does not participate in gas exchange with the lungs (see). Notice the effect of the dead space in reducing the quantity of air available in the alveolar sacks for gas exchange with the blood is higher with higher frequency of breathing; at the frequency of 40 breaths per minute, the alveloar volume is zero.

Table of Breath Frequency and Tidal Volume Vt and Alveolar Volume V_a

This data in this table leads to the following observations:

1. Air intake or tidal volume per breath in autonomous breathing at rest increases with reducing breath frequency
2. Maximum resting alveolar volume of air available for gas exchange in autonomous breathing is 4.8 liters/min
3. Oxygen uptake by an individual is a fraction of the oxygen available for uptake in the alveoli
4. The effect of dead space on alveolar volume decreases with decreasing frequency of breath 

The table above shows two rows of numbers indicating the possibility of dramatically increasing tidal and alveolar volumes per minute with moderate and heavy exercise. Significant increases in the volumes are due to due to increase in oxygen demand by the locomotive muscles resulting in an increased sympathetic activity dilating of airways. Respiration is still autonomous. There is more oxygen demand and nature fills this demand autonomously until fatigue sets in and shuts it down. 

While exerccise has a siginfant health benefit of increased oxygen uptake but it comes at a cost of increasing the activity of sympathetic division of the autonomic nervous system while human condition is already defined by sympathetic dominance resulting from inbuilt survival instincts. Physiological literature amply describes the ravages of stress resulting from our sympathetic dominance.

Is there another way to increase oxygen uptake? Yes, there is. The answer lies in reaching out of the boundaries of the autonomic respiration. Although, respiration is an autonomic activity, it is so with a difference. While other autonomic body functions like beating of the heart, circulation of the blood, digestion of food, etc. are not open to our volitional control, respiration is (see). While all autonomic functions including breathing are neurally controlled by the brain stem, breathing yields this automic control to volitional control by the cerebral cortex. 

Traditional health care fails to realize this difference because of its underlying Decartian model of body-mind duality. Voluntary control of respiration can be exploited to increase oxygen uptake with little extra effort; much  nore of an effort is needed by exercise.