Muscle cramps are involuntary muscle contractions that last for a few seconds to several minutes, usually accompanied by intense pain. Common causes of cramps include muscle fatigue, body dehydration, electrolyte imbalance, poor blood circulation and nerve damage, which is why prolonged exercise or holding the same posture for a long time easily have muscle cramps.
Muscle cramps during exercise is due to muscle fatigue. Exercising consume liver sugar as a source of energy. When the consumption is too fast, such as running, or body does not have enough energy to support the activity, such as running marathon, it is likely to cause muscle cramps. Secondly, when sweating, the body will lose water and electrolytes, leading to dehydration and electrolyte imbalance, which is also likely to cause cramps.
Muscle cramps during sleep is caused by the bad blood circulation. Low temperature will make the blood circulation slow down. Excessive exercise during the daytime lead to muscle fatigue, which may also cause muscle cramp during sleep. For elderly, drinking too much tea and coffee, which cause the body relative dehydration or electrolyte imbalance and lead to muscle cramps.
Holding a certain position for a long time will also cause cramp. It is caused by poor local blood circulation with muscle fatigue, which is why wearing the high heels for a whole day easily to have cramps.