Monday, October 18, 2010

Breathing during Exertion

A reader sent me this question:

I know that one is supposed to exhale on the heaviest exertion of a movement or exercise (right?)….But can you say more about breathing and moving; breathing and exercise; breathing and stretching? What is the science behind this breathing?
Great question, thanks. Yes, the common belief is that you should be exhaling when you exert.
There is no scientific, chemical reason why you should be exhaling, it is all about the mechanics. When we exhale, it recruits the muscles of the core. The abdominals the obliques and the lower back muscles can all be involved in a vigorous exhale; the kind that is recommended during a strenuous movement.  The reason this type of breath is recommended is simply for the recruitment of those muscles to support  your spine during the exertion. 
Another factor is that when we are exerting it can increase the pressure inside your body.  It is instinctive for people to hold their breath during an exertion because this further increases the internal pressure and therefore increases the muscular support during the movement.  However, it is very easy to create too much pressure this way.  So it is for this reason that we are advised to exhale on exertion.
There can be other factors contributing to whether or not you should inhale or exhale, too.  For example, in a movement that brings your knees up into your chest, exhaling would be a good idea simply to give your legs the room.  If you inhaled, and inflated your lungs, there would be more volume to your torso and therefore it would be harder to pull your knees in. 
In yoga it is often advised to inhale when you are extending your spine and to exhale when you flex it. This has to do with the diaphragm being stretched. When you inhale, the diaphragm contracts, which causes it to lower into your abdominal cavity. When this action is combined with a spine extension, there are two opposing forces pulling on the torso: the diaphragm from below and the upper thoracic viscera from above by the nature of spinal extension.  On the other side of that coin, when your spine is flexing, you are able to relax the diaphragm, which causes it to pop back up into your ribcage.  You can also use the act of the flexion of your spine to assist you in emptying the air from your lungs. 
When people are stretching, I advise deep breathing both in and out, with the greater emphasis on exhaling.  There is a natural, inherent relaxation of the body with the act of exhaling (even though it is actually the contraction of the diaphragm that initiates it). When holding a long stretch, paying attention to the exhalation and the accompanying relaxation can lead you to a longer, deeper and more effective stretch. 
And one final thing I want to say about breathing.  Its main and most important function is not to bring you oxygen as is commonly believed.  True, that is one of the functions, but the most important function is actually the removal of carbon dioxide. All the time, but especially as we exercise, our bodies are converting oxygen to carbon dioxide.  And we have to get rid of it.  The ‘out of breath’ feeling that you get is not your body telling you it needs more oxygen.  In fact, when you breathe out, that air contains enough oxygen supply for another full breath in. No, what that feeling is, is your body trying to dump off all of the accumulated carbon dioxide.
So the next time you are exercising and you feel like you are running out of breath, focus on exhaling more deeply and see if that helps you ‘catch your breath.’
Please keep the questions coming.  
Is there anything you want to know about health and fitness, but have been afraid to ask?  Is there a subject that I haven't addressed that you'd love to read about? 
Please let me know; I love to research and write about this stuff. 

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