What is a Muscle Cramp?
House Call Doctor explains the science behind muscle cramps.
House Call Doctor
We all get muscle cramps from time to time. But what are they really? And what causes them?
Muscles have two states: relaxed and contracted. A muscle is relaxed when all of the fibers within the muscle are elongated. When the muscle does its job, calcium goes into the muscle cells and sodium rushes out. Doing so causes the fibers to shorten and the muscle to pull — doing its work. That is not a problem in the short term, when the muscle is doing what it’s supposed to do. But when a muscle stays contracted, a sharp and intense pain occurs, leading to a cramp.
One reason cramps occur is a decreased supply of oxygen. If you’ve ever gotten a “stitch in the side” when exercising, you’ve experienced this phenomenon. When the work of the muscle outstrips the flow of blood and supply of oxygen, the muscles cramp up.
Muscle cramp photo courtesy of Shutterstock.