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| English: Heart and lungs (Photo credit: Wikipedia) |
How much air do you take in with each breath?
A little more than half a litre when you are resting (shallow breathing). And as much as over four litres when you are taking deep breaths or running or exercising.
Why is it harmful to hold your breath for more than a minute or so?
It is because your body would not receive its normal supply of oxygen.
It would also not be able to get rid of waste gases that can poison your blood stream. When you hold your breath, two things happen: the supply of fresh oxygen is cut off from your lungs and, therefore, from the rest
of the body;and the lungs fill up with waste gases (mainly carbon dioxide) that escape when you breathe normally.
Why do you breathe more deeply when you run?
When you run you use up more energy. This energy must come from the combination of oxygen with the stored nourishment in the cells.The process of combination must take place on a larger scale than usual. To bring this about you need more oxygen in your blood.
By breathing more deeply you get more oxygen in your lungs and, thereby, more oxygen in your blood.
