Magnesium and Cramping

On a recent mountain biking adventure Psycho Dave, one of the better riders I know, started coming down with cramps.  Bad cramps, all over his body.  It was so bad he had to walk out of the park we were in, and it took quite a while before we were able to get him in a car (he couldn't drive himself) and get him home.  We were ready to dial 911...

What was the problem?  Dave had been chugging some wacky sports drink with a lot of magnesium.  Once he got his magnesium levels under control (I don't recall how) he was fine.  It took a few hours.

Dr. Davis has a bunch of really interesting posts on magnesium:

"Magnesium regulates muscle contraction. Leg cramps, or 'charlie-horses', painful vise-like cramps in calves, fingers, or other muscles, are a common symptom of magnesium deficiency."

Hmm... I've been prone to these.  Better lately, although I still occasionally get cramps in my fingers.  I recently had my magnesium levels tested, and they came back at 2.1 mg/dL, a level Dr. Davis considers to be on the low side of normal, although he notes:

"Blood magnesium levels are a poor barometer for true body (intracellular) magnesium.

"Only 1% of the body’s magnesium is in the blood, the remaining 99% stored in various body tissues, particularly bone and muscle. If blood magnesium is low, cellular magnesium levels are indeed low—very low.

"If blood magnesium is normal, cellular or tissue levels of magnesium may still be low. Unfortunately, tissue magnesium levels are not easy to obtain in living, breathing humans. In all practicality, a blood magnesium test only helps if it’s low, while normal levels don’t necessarily mean anything and may provide false reassurance

He also discusses heart arrhythmia and magnesium:

"In fact, in the hospital we give intravenous magnesium to quiet down abnormal rhythms."

I had a heart arrhythmia a few years ago, and my father and my grandmother both have atrial fibrilation, which Dr. Davis says are indicitive of magnesium problems. Wheat is also implicated, naturally:

"Do you suffer from fatigue or heart problems that might be caused by magnesium deficiency? Have you diligently consumed a 'smart' diet of whole grains, legumes, and low-fat dairy as per the recommendations of your dietician and doctor?"

All food for thought for the athelete suffering from frequent cramps.  But don't over-supplement, if you choose to supplement.

Here are some more interesting reasons to think about magnesium.