by Bob Albright, D.O.

It’s finally racing season for many of us and it’s heating up both literally and figuratively. The early season often prompts the most questions about this condition, as we finally “go for it” after months of solid preparation -- my topic this month is the muscle cramp.

Arguably, cramps are worse than the bonk, since often we still have the will, but not the means to keep racing in the face of these often disabling, painful monsters. The bonk… well, you all know. So how can we prevent cramps?

Not to worry, I will not go into detail on the somulence-inducing theories of why we cramp, using terms like feedback inhibition, golgi-tendon apparatus, resting potentials and the ilk. Rather what follows is a list from a nephrologist and ICU doc, who is passionate about preventing cramps himself during races.

One thing first: we do not fully understand what causes cramps. Now that I will not be restricted to any real “facts,” here we go:

Train for race stress: Many experts believe the main reason we cramp is we push the muscles way past the fatigue threshold. Thus we induce stresses our muscle units have not experienced and blammo, bone breaking cramp.

Train for eccentric stresses: Eccentric stress involves placing a load on a muscle as it is lengthening. I have written about the powerful benefits eccentric loads induce from a rehab potential in a prior article. However, from a cramping perspective, eccentric loads such as down hill running are a common stimulus for cramping. If your race has an undulating course, find similar training terrain. Think fast foot-strike, quick turnover and try not to “brake” while running downhill.

Avoid dehydration: I know, I know… I've previously written that you can “safely” be up to 4% dehydrated as a full distance triathlete without any performance detriment. However, as a dialysis provider, I personally witness the agonizing cramps dialysis patients suffer as we attempt to remove fluid too rapidly or in excess quantity. These cramps resolve immediately with infusion of volume. So, while it is certainly overly simplistic to blame all cramps on “dehydration” (a better term may be decreased effective circulating volume), dehydration will predispose you to cramps. So I think it’s imperative that you know your sweat rate:

1. Weigh yourself naked and empty before your exercise.
2. Exercise, then reweigh (after emptying) yourself, recall how much you may have drank during the event.
3. Subtract the second weight from the first and add the amount of fluid in ounces you consumed, finally correcting this to an hourly rate.
4. Voila! Your sweat rate in ounces (pounds for some of us) per hour. Water is sufficient to replace this loss for exercise up to an hour.

Keep some sodium coming in: Your sodium losses per hour will be at most 140 mg per liter of fluid lost per hour and most times much less than this. You are getting plenty of sodium if you are taking in 200-400 mg/hour. You can overdo the sodium if you stop drinking water. Fortunately, high sodium levels occur very rarely during an athletic event in the absence of hormonal or kidney dysfunction.

Supplement a little potassium and magnesium This is perhaps more important if it is an event lasting more than three to four hours. The amounts of magnesium and potassium required are quite small. Since your sweat has such small amounts, unless you are battling diarrhea, you will require only trace amounts which are usually found in sports drinks. Care must be utilized with magnesium supplements as they can cause diarrhea. Excess potassium can be dangerous if you have kidney dysfunction or are taking certain diuretics or blood pressure medications. Certain diuretics may cause a depletion of these electrolytes, so I’d suggest asking your medical provider about these issues.

Try calcium if you are still cramping after attention to the above: Again, I suggest being cautious with the amounts, as when we are a little dehydrated any excess calcium will be excreted by our kidneys with a load of sodium and water (see above!). One 500 mg tablet of calcium carbonate every other hour will be sufficient.

What about quinine? Just say no. The FDA recently removed quinine sulfate 324 mg from the market when utilized for cramps. The narrow windows of toxicity, including cardiac rhythm catastrophes lead to its ban. The amount of quinine in tonic water is 20 mg, thus allowing it to remain. Quinine is allowed to treat malaria, though most strains are now resistant.

I hope these suggestions are useful, and for those of you who are still cramping despite attention to all the above, it is appropriate to have some basic blood work and an exam by your provider. There are unusual conditions which may only come to light with the appropriate testing.

Cheers and good luck to all.