Why breathing fresh air is vital?

A hiker on a cliff.

Have you ever enjoyed the experience of getting away from the smoke polluted atmosphere of the larger city into the clean, stimulating fresh air of the open countryside?

Of course you have.

You took a deep breath.

Immediately you felt the invigoration.

Depression and lethargy began to shake off.

What a wonderful sense of well-being!

Instead of merely taking for granted this swift and refreshing transformation, why not pause and ask some pertinent questions?

Why is fresh air so beneficial?

Why is air so vital‘ to life itself?

What happens when you take a deep breath, filling your lungs with this precious substance?

Getting an understanding of these matters aids one to build up appreciation for the makeup of our respiratory system.

What is air?

We humans live at the bottom of a vast ocean of air that envelops the earth.

This ocean consists of a mixture of gases in fairly regular proportion.

The most important of these, a component of air that is essential for us to keep alive, is oxygen.

This is what the body uses, combining it with carbon from food eaten, to build up energy needed for the multiplicity of bodily processes.

Oxygen makes up about one-fifth of the total volume of air.

The other components of the gaseous envelope in which we spend our lives are nitrogen, making up about four-fifths of the total volume, and carbon dioxide, of which there is less than one percent.

Realizing that all the food in the world would be quite useless to us without oxygen, we can afford to be curious about how the body uses the oxygen we breathe in.

What part do the lungs play?

Just how is this vital element of the air converted into a fund of energy?

The lungs  

Let us take note of the lungs and their function.

Take a deep breath and feel your lungs expanding to fill the chest cavity below the ribs.

The lungs are roughly conical in shape, with the narrow ends uppermost.

Like the bellows of an accordion, yes, but much more complicated inside.

Imagine the movement of air taken in through the nose into the windpipe or “trachea," a tube having a diameter of about three-lifths of an inch.

After about four inches this “trachea” splits into two branches, called “bronchi," leading into each of the lungs.

Once inside the lung. each “bronchus" divides yet again into smaller branches, which, in turn, keep subdividing into smaller and smaller tubes filling the interior of the lung.

To get a clearer idea of this amazing structure inside the lung, just imagine an inverted tree with a main stem four inches long dividing into two branches and then subdividing again and again to terminate in clusters of the tiniest twigs.

Only, instead of twigs at the end of those minute passageways, the smallest being known as “bronchioli,” there are clusters of tiny air spaces, “alveoli,” as they are called.

The “bronchioli,” by the way, have a width of only about one-hundredth of an inch.

Exchange of oxygen

Note, now, those “alveoli” or tiny air spaces grouped together at the extremities of the “bronchial” tree.

It is here that the oxygen filling these air spaces is transferred to the cells of the bloodstream.

Intertwined with the subdividing branches of the air tubes within the lung, there is a network of arteries breaking down into veins and minute capillary blood vessels,

The vessels are so small that eventually the red blood cells are moving through in single file.

By the time that the extremities of the air tubes are reached, the walls separating the air tubes from the capillary blood network are so exceedingly thin that the transfer of oxygen to the bloodstream becomes possible.

It is a two-way transfer, for at this same location the blood discharges its waste cargo of carbon dioxide into the air spaces, to be expelled by lung action back into the atmosphere.

Meantime, the oxygen-enriched blood moves back through capillaries and veins to the heart, from there to be pumped. through the body again.

Intricacy of the breathing system

According to one authority, there are an estimated 750 million of these tiny air cells in our lungs, ensuring a constant and plentiful supply of the vital oxygen for all the complicated processes going on inside the body.

This might be compared to a vast exchange area, connecting, let us say, road and rail traffic, with 750 million loading and unloading platforms.

All that within the small compass of the chest cavity!

If all those air spaces at the extremities of the “bronchial” tree were opened out and spread flat, it is believed they would cover an area of some 1,000 square feet.

That is the equivalent of sixteen blankets, each measuring seven by nine feet!

Little wonder, then, that humans would find it far more difficult to produce an artificial lung than to make an artificial heart.

And another amazing feature of our breathing apparatus is that no matter how hard we try, we just cannot empty our lungs.

There is always a large residue of air left in the bronchial tubes and air spaces.

In normal breathing, it is claimed, only about one-tenth of the total volume of air passes out of the lungs.

And the process of exhaling and taking in a fresh supply is repeated eighteen to twenty times each minute.

Transport of oxygen

That so little is expelled at each exhalation raises the question as to how a good, constant supply of fresh air is guaranteed to the exchange units at the extremities of the “bronchial" tree.

And here is where a basic law of the universe comes into operation, making possible the transport of oxygen from the outside atmosphere to the inner cells of our bodies.

It has been found that two samples of the same gas, say oxygen, at different pressures, when brought into contact with each other, will mix and diffuse until an equalizing of the pressure takes place.

So, the highly concentrated incoming oxygen swiftly mixes with the oxygen depleted air already in the lungs, and in this way the level of oxygen at the exchange points is constantly maintained.

The same principle applies in the actual exchange of oxygen from the air spaces to the bloodstream.

The exceedingly thin walls at these terminal points allow the same diffusing of oxygen, so that the concentration in the bloodstream is built up and maintained.

The red blood cells absorb the oxygen, carry it to the millions of cells throughout the body, and there it is used to burn up the food eaten.

Since food eaten combined with oxygen breathed in is the energy source for all body activities, we can understand why we often have to struggle for breath after any particularly strenuous exercise.

Energy spent leaves our oxygen supply depleted.

The importance of a constant supply of oxygen is underlined by the fact that only a few minutes of oxygen starvation can cause irreparable brain damage.

Our illustration of the inverted tree with its branches representing the bronchial system is all the more apt when we learn that in reality trees and plants operate in a converse manner in relation to animal creatures, and have a great deal to do with the maintenance of the vital oxygen supply on our planet.

For, while the breathing creatures take in oxygen and throw off carbon dioxide, plants with their intricate mechanisms take in needed carbon dioxide, during the sunlight hours, and release oxygen into the atmosphere.

Also, we can begin to have some appreciation of fresh air as distinguished from the contaminated air of many industrial regions.

Investigation has shown that Eskimos and others who live in a dust-free atmosphere retain the original rose-pink color of the lungs, while the lungs of coal miners become a shade of almost uniform jet black.

The black and dirty condition of city buildings also bears witness to the hazard to which the lungs of city dwellers are subjected.

Opportunities to get away, even if only temporarily, from polluted atmosphere are really opportunities to learn what it feels like to for us to breathe fresh air.

So when you take a deep breath, be thankful for the abundant provision of the air enveloping atmosphere and marvel at amazing breathing system that keeps us alive.