Side Stitch

You are running — and suddenly something bores into your side. A sharp, pulling pain, often under the right ribs, sometimes on the left, sometimes on both sides. Every breath sharpens it. You slow down. You bend over. You press your hand to the spot as if you could pull out the invisible stab. And then, after a few minutes of walking, it is gone again — as if nothing had happened.

Sports medicine has plausible explanations for this: the diaphragm, that dome-shaped breathing muscle between the chest and abdominal cavity, gets into a conflict during physical exertion. It is supposed to breathe powerfully and at the same time keep a full stomach or irritated ligaments in check. It becomes over-acidified, it cramps, it protests. That is the mechanical explanation. It is not wrong — it is simply not complete.