Spasms occur when muscle fibers contract involuntarily. There are three types of muscle fibers: skeletal muscles, smooth muscles and cardiac muscles. Smooth and cardiac muscles control involuntary functions such as digestion and heartbeat. Skeletal muscles are the muscles that move voluntarily during walking, running and writing. Sudden muscle spasms usually occur in skeletal muscles. Understanding the causes can help reduce the incidence of these painful and disconcerting spasms.
Overuse
Overuse of muscle is a common cause of spasms. Strenuous exercise can result in muscle cells running out of energy, which leads to strong involuntary contractions. These spasms can be avoided by not exercising to the point of exhaustion. If a spasm occurs during exercise, it is important to take a break and rest the muscle. Massage and intermittent application of heat may also bring relief. It may be necessary to decrease exercise intensity to avoid muscle cramps.
Dehydration
According to Medline Plus, dehydration is the most common cause of muscle spasms occurring during strenuous activity. Muscles require an adequate supply of water to function correctly. They must also have electrolytes and certain vitamins for voluntary muscle movement to take place. If these elements are lacking, muscle spasms can result. Avoiding dehydration by drinking the recommended eight glasses of water per day is beneficial. Drinking even more water when exercising--- on especially hot days---is another helpful strategy. Sports drinks containing additional minerals and electrolytes may be useful for relieving cramps caused by dehydration.
Disease
Certain diseases can cause muscle spasms to occur. Diseases affecting nerves or blood vessels are especially noteworthy for causing muscle spasms. This is because an adequate blood supply and nerve stimulation are vital for muscles to function properly. Atherosclerosis, or narrowing of the arteries, prevents enough blood from reaching the muscles. Nerve diseases such as multiple sclerosis cause muscle spasms by affecting electrical signals from the brain that control muscle activity.
Stroke is another condition that affects neurological conductivity to the muscle. The National Stroke Association notes that individuals suffering from stroke-induced spasms may have arms tightly coiled into fists or tightly pressed against the chest.
