This is a prolonged and painful spasmodic muscular contraction that often occurs in the limbs, especially the legs, but can also affect certain internal organs like the colon.

Cramps may result from imbalance of sodium in the body, as in heat cramps. Working in high temperatures causes excessive sweating and consequent loss of sodium content in the body. It can be corrected and prevented by increasing the intake of salt. Occupational cramps result from continual repetitive use of particular muscles, for example, writer's cramps. Night cramps occur during sleep and is especially common among elderly people, diabetics and pregnant women.