Muscle spasms, or cramps, are painful and involuntary contractions of the muscles. Cramps can sometimes be stopped by stretching the muscle, and many athletes regularly stretch their muscles as a precautionary measure, but inadequate calcium could still be a precipitating factor.
Calcium
Calcium is a mineral the body uses in a variety of ways. It is necessary for blood vessels to contract and dilate, for nerve transmissions, hormonal secretion and muscle function. Although calcium is the most abundant mineral in the body, the level of calcium in the blood is very tightly controlled; the body uses bone tissue as a reservoir and moves calcium into the blood, muscles and intracellular tissue stream as necessary. The muscle fibers use calcium as a signaling mechanism, and disruptions in calcium regulation can affect the muscles. In fact, according to Katherine Zhou, writing for "Yale Scientific Magazine," calcium is one of the reasons that the body develops rigor mortis, because rising calcium levels inside the cells cause muscle contraction, and there is no longer a compensating mechanism to cause relaxation.
Heart Muscle
It's important to remember that while muscle cramps are often thought of as relating to the legs or arms, they can occur in any part of the body. In addition, the heart is a muscle, perhaps the most important muscle of the body, and changes in calcium affect the heart muscle. According to Lab Tests Online, large fluctuations in calcium can cause the heart to beat more rapidly or to slow down, and can even cause muscles to go into the continuous spasm known as tetany.
Medical Conditions and Muscle Spasm
Muscle spasms are a symptom of several medical conditions, including alcoholism, hypothyroidism, kidney failure, metabolic problems and pregnancy. Alcoholism and hypothyroidism are known to interfere with calcium metabolism, and higher levels of calcium are required during pregnancy and lactation.
Calcium Intake
Calcium is a mineral most people can obtain through a good diet. The Office of Dietary Supplements' recommendations for calcium intake vary according to age and gender; the range is from 260 mg for a child age 7 to 12 months up to 1,300 mg for a lactating female. Good sources of calcium include milk products, brassica crops such as kale and broccoli, and calcium-fortified foods. However, humans only absorb about 30 percent of the calcium in foods. Calcium supplements are also available. While the risks are relatively low, before starting calcium supplements, it would be wise to consult with a health care professional, as too much calcium can be a factor in kidney stones for some people.
References
- MedlinePlus; "Muscle Cramps"; Dr. Linda Vorvick et al;July 2010
- American Association for Clinical Chemistry; Lab tests Online; "Calcium"; October 2010
- "Yale Scientific Magazine"; "Everyday Q&A: What Causes Rigor Mortis?"; Katherine Zhou; February 2010
- Office of Dietary Supplements: Dietary Supplement Fact Sheet -- Calcium
- "Physiological Reviews"; "Calcium Ion in Skeletal Muscle -- Its Crucial Role for Muscle Function, Plasticity, and Disease; Martin W. Berchtold, Heinrich Brinkmeier"; Markus Müntener; July 2000
