Behind each breath an under appreciated muscle

Some muscles get all the glory. Bodybuilders show off their swollen triceps; sprinters flash their sharp-edged calves. But deep inside all of us, a sheet of muscle does heroic work in obscurity.

In order to breathe in, we must flatten the dome-shaped diaphragm; to breath out, we let it relax again. The diaphragm delivers oxygen to us a dozen times or more each minute, a half-billion times during an 80-year life.

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