What Causes Muscle Spasms?

A spasm is a temporary burst of energy, activity, emotion,stress, or anxiety, causing a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, (like the liver) or a sudden contraction of an orifice. They may be experienced with a sudden burst of pain, but are usually harmless, lasting for only for a short period. Spasmodic muscle contractions are also a result of many medical conditions.

A muscle spasm is different than a twitch, which is an uncontrolled fine movement of a small segment of a larger muscle that can be seen under the skin. Muscles are complex structures that cause movement in the body. There are three types of muscle in the body; the cardiac muscle that pumps blood, skeletal muscle that moves external body parts, and smooth muscles that move hollow structures inside the body.

Skeletal muscles are directly attached to bone or by a tendon. When these muscles contract we are able to move things like our arms. These muscles are controlled by the brain and require numerous steps within cells and fibers using oxygen, electrolytes, and glucose, which are supplied by the bloodstream.

Smooth muscles are located in arteries, intestines, bladder, and the iris of the eye and are controlled by the unconscious part of our brain function using the autonomic nervous system. They have the same basic contraction mechanism as skeletal muscle, though different proteins are involved.

Voluntary muscle contractions happen when electrical signals are sent from the brain through the spinal cord via nerve cells called motor neurons. Chemicals are then released by the motor neurons and stimulate the internal release of calcium ions from stores within the muscle cell. These calcium ions then interact with muscle proteins within the cell, causing the proteins to move. This motion shortens the cell and, ultimately, the muscle itself. Unlinking the actin and myosin and recapturing the calcium allows the muscle fiber to relax. Abnormal contraction may be caused by abnormal activity at any stage in this process.

Spasms can occur when a muscle is overused and tired, which may result from it being overstretched or being held in the same position for an extended period of time. This causes the muscle cell to run out of energy and fluid, developing a forceful contraction. It can involve part of a muscle, the whole muscle, or even adjacent muscles. This type of spasm is usually a signal that it is time to rest. Ignoring warning signals can lead to such severe energy depletion that the muscle cannot be relaxed, causing a cramp.

Dehydration and depletion of electrolytes also lead to muscle spasms and cramping. Your muscles require adequate water, glucose, sodium, potassium, calcium, and magnesium to allow the proteins within muscle cells to interact and develop an organized contraction. A lack of these elements can cause the muscle to become irritable and go into spasm. Loss of fluids and salts can disrupt ion balances and can prevent muscles from responding and recovering normally, leading to cramps.

Atherosclerosis (narrowing of the arteries) can also trigger muscle spasms and cramps. This occurs when plaque builds up in the arteries, blocking them and resulting in insufficient blood supply and nutrients to the body’s muscles.

Systemic illnesses like diabetes, anemia, kidney disease and thyroid and other hormone issues are also potential causes of muscle spasms. Multiple sclerosis, stroke, cerebral palsy, neurodegenerative diseases, spinal cord injury, and nervous system poisons such as tetanus, can be associated with muscle spasm as disruption of brain mechanisms.

Dystonias are movement disorders where groups of muscles forcefully contract, causing twisting and repetitive movements, inhibiting a normal posture as a result of muscle spasm and cramping. Symptoms can be mild or aggressive. Examples of this type of muscle spasm are when neck muscles cause the head to turn to one side.

Here are some tips to use when dealing with muscle spasms:

1. Drink plenty of fluids and replace electrolytes when you're exercising or sick.

2. Stretch the affected muscle. This can stop the painful contraction cycle of the spasm and relieve the pain.

3. Use a heating pad. Heat causes muscles to relax and stops spasms.

4. See a doctor for treatment of an injured muscle that is causing continuous or repeating spasms.