Muscle Cramps

Commonly affected muscles include the calf muscles in the back of the lower leg, hamstring muscles in the back of the thigh, quadriceps muscles in the front of the thigh, the abdominal wall, arms, hands, and feet.

The intense pain of a muscle cramp can wake you at night from a sound sleep, or make it difficult to walk. A sudden, sharp pain lasting from a few seconds to minutes is the most common symptom of a muscle cramp. 

Cramps can result from intense bouts of exercise. Dehydration is another main cause of cramps, but it does not need to be exercise induced. Dehydration is not only the excessive loss of fluids in the body, it is also the lack of fluid replenishment. If you are not an exercise person but drink large quantities of beverages that have a diuretic effect (such as coffee, tea, alcohol or carbonated drinks) you are dehydrated. This type of self-induced dehydration can cause cramping of skeletal muscles.

Low levels of minerals in the diet (low electrolytes) can also result in muscle cramps. Calcium, potassium and sodium contribute to healthy muscle function and, when depleted, result in muscle cramps.

Poor blood supply to your legs and feet can cause cramping in those areas when you exercise, walk, or participate in physical activities. If the blood flow has been low for a long period of time, the cramps may occur at rest as well. While this can be common in patients with diabetes, there are several medical conditions that can also restrict peripheral blood flow.

Medical conditions that can cause muscle cramps include:
1.  Compression of spinal nerves, seen in conditions such as degenerative spinal stenosis, which can cause muscle cramps in your legs when walking or standing for long periods of time.
2.  Hypothyroidism (low thyroid gland function) which has direct effect on calcium metabolism and will result in generalized muscle cramps.
3.  Alcoholism.
4.  Pregnancy.
5. Kidney disorders.

Prescription medications are perhaps one of the most common causes of muscle cramps in the American population. Medications used for blood pressure, cholesterol, congestive heart failure, or respiratory disorders can cause cramping for different reasons. For instance, statin drugs commonly used to treat high cholesterol can cause a condition known as rhabdomyolysis, or a breakdown of skeletal muscle causing muscle fibers to be released into the blood stream. This is usually the cause of statin related cramping. Various blood pressure medications increase the excretion of electrolytes such as calcium, potassium, and sodium. Low levels of these electrolytes and minerals can result in muscle cramps.

Muscle cramps are very common in the elderly population. Unfortunately, muscle cramps in this population can be multi-factorial. For instance, an elderly patient may be taking a combination of statin drugs for high cholesterol, and a blood pressure medication, be sedentary, and have advanced degenerative changes in the lower back. Therefore, leg cramps in this example may be caused from muscle breakdown (rhabdomyolysis), low electrolytes, nerve compression, and/or sarcopenia or age related atrophy and wasting of skeletal muscle. As simple a symptom that muscle cramps seem to be, there are many causes and depending on the patient’s medical history, may be very complicated and difficult to diagnose.

Extracts taken from "What causes muscle cramps?" by Dale J. Buchberger, PT, DC, CSCS, DACBSP

Stay hydrated.

When you start sweating because of heat or exertion, you lose salt (sodium) and other electrolytes, and the fluid in the space between your muscles, or interstitial space, shrinks.  “When that space shrinks, the nerve-to-muscle connection becomes hyper-sensitive,” explains Michael Bergeron, PhD, FACSM, director of the Environmental Physiology Laboratory at the Medical College of Georgia.  “You begin to get little twitches that can eventually evolve into full-blown muscle cramps.”  This type of cramping can spread throughout your body because the interstitial space is compromised all over.  To prevent it, take steps to avoid dehydration.

To ensure you are consuming the right amount of fluids, measure your personal sweat rate, suggests Monique Ryan, MS, RD, author of Sports Nutrition for Endurance Athletes (VeloPress, 2007).  Simply weigh yourself immediately before and after a one-hour workout.  The amount of weight you lost is known as your sweat rate.  Ryan recommends consuming 20 to 24 ounces of fluid for every pound of weight lost to replace both sweat and urine losses.  Take a drink break every 15 minutes, and if your workout lasts longer than an hour, she suggests drinking a sports drink.  The salt helps replace electrolytes, and the carbs keep your muscles fueled.

Also be mindful of the weather’s effect, advises Bergeron.  “In the cold, especially when you put on a lot of layers, you don’t realize you’re sweating,” he says.  “Plus, if the air is dry, sweat is evaporated very quickly; you may be losing fluid and not recognizing it.”

Avoid acid-forming foods.

Some nutritional experts believe that acid-promoting foods deprive the body of minerals and can lead to muscle cramps.  “Foods high in phosphorous, such as red meats, will deplete calcium and magnesium,” says Zoltan Rona, MD, a complementary-medicine physician in Toronto.  “So will anything containing caffeine, like coffee, soft drinks and chocolates.”  Other top acidity promoters are processed sugars, refined flour and dairy products.  For foods that alkalize the body and provide additional cramp-minimizing effects, look to sweet potatoes, bananas and carrots (for potassium); nuts, beans and oat bran (for magnesium); and dark, leafy greens (for calcium).

Train your muscles properly.

 Whether you’re in the middle of a 10K ski race or at the end of a tough weightlifting workout, asking too much of your muscles can cause them to cramp.  “Fatigue sends signals that tell the muscle to contract more than necessary for the action, while simultaneously decreasing signals that tell the muscle to relax,” says Carol Torgan, PhD, FACSM, a Washington D.C. based kinesiologist.  “Hence the intense contraction.”  If you feel a cramp in a particular area, such as the calf or quadriceps, it could be from overexertion, says Torgan - or, put another way, it could be from inadequate training.  Her advice for preventing fatigue-related cramps is simple:  “Practice, practice, practice.”  If your muscles are prepared for what you plan to ask of them, they won’t become as fatigued.  Follow a training plan that corresponds to your athletic level and goals in the months before a competition, and eat enough carbohydrates during activity to continually fuel the muscles with glycogen.

Monitor your medications.

“Certain medications can dehydrate you or cause problems with neuromuscular firing,” says Bergeron.  So read the fine print on potential side effects.  Cramp-causing drugs include diuretics and prescription medications for asthma, high cholesterol, high blood pressure, Parkinson’s disease, Alzheimer’s disease and osteoporosis.  Ask your doctor about any medications you’re on - prescription or over-the-counter - before undertaking exercise.