by Gabe Mirkin, November 11, 2007
www.drmirkin.com
used by permission

Exercisers are often told that muscle cramps are caused by lack of salt (sodium) or low potassium. However, recent studies show that athletes in endurance events who suffer cramps usually have normal sodium and potassium levels. A review of the current literature from Buenos Aires, Argentina shows that doctors don't know very much about exercise-induced muscle cramps (Journal of the American Academy of Orthopaedic Surgeons, July 2007). The most common cause appears to be muscle damage. Athletes may be able to prevent cramps by slowing down when they feel the muscle pulling and tightening, and picking up the pace only when the muscle feels good again. Cramps may occur as a side effect of drugs used for high cholesterol, high blood pressure or diabetes. Oral contraceptives, various other drugs or alcohol can also cause muscle cramps. If you suffer from recurrent muscle cramps that cannot be explained,
check with your doctor. Possible causes include pinched nerves, Parkinson's disease, hypothyroidism, diabetes, narrowed arteries, low blood mineral levels, or metabolic diseases that cause muscle damage. However, most exercisers who experience exercise-associated muscle cramps do not suffer from disease and can usually prevent cramps by slowing down when their muscle start to feel tight. Athletes are usually not willing to do this during competition, so they will continue to suffer from occasional cramps and work them out as they occur.

Cramps Probably Caused by Muscle Damage

by Gabe Mirkin, March 16, 2008
www.drmirkin.com
used by permission

Even though muscle cramps are extremely common in competitive athletes, we really do not know what causes them. Nobody has shown consistent benefit from any of the most common treatments: multivitamin pills; mineral pills with calcium, zinc, magnesium, salt and/or potassium; massage or chiropractic manipulation; drinking large amounts of water; dietary manipulations; or bio-mechanical stretching and strengthening. Known medical causes of muscle cramps are extremely rare in athletes. These include narrowed blood vessels, usually
from atherosclerosis; compression of nerves, low thyroid function, or side effects of medications such as diuretics. Some cramps are caused by low mineral or fluid levels (The Japanese Journal of Clinical Pathology, November 2007). However, for the vast majority of people who suffer exercise-associated muscle cramps, blood levels of sodium, potassium, calcium and magnesium are normal. Research in athletes after they ran in 52-mile races showed that the runners who suffered cramps had the same level of dehydration and blood mineral levels as those who did not get muscle cramps. Cramping during exercise usually occurs in healthy people without any underlying disease or known cause. I think that the most common cause of exercise-associated cramps is damage to the muscle itself. Before you get a cramp, you will probably feel that muscle pulling and tightening. If you slow down, the pulling lessens, but if you continue to push the pace, the muscle goes into a sustained cramp and you have to stop exercising to work the cramp out. Further evidence that muscle damage is the cause of the cramp is that the muscle often hurts for hours or days afterwards. You may be able to prevent cramps by exercising more frequently but less intensely and for shorter periods of time, but most serious exercisers do not want to do this. There is some evidence that taking sugared drinks and foods during prolonged exercise helps maintain endurance and muscle integrity which helps prevent cramps. So take a source of sugar every 30 minutes or so during a vigorous workout, and back off if you feel a group of muscles pulling and tightening during exercise. Most exercisers just accept that occasional cramps will occur and cause no long-term harm.