by Stephanie Mumford Brown
It’s the end of a perfect running day. Those miles you put on earned you a second helping of lasagna and an extra brownie.
Now you’re tucked into bed, taking a last luxuriant stretch before sleep, and aaargh! yikes! jump out of bed, jump up and down, work your fingers into it, stretch it out, yowchie ouchy OUCH!!! You’ve got a leg cramp.
Maybe you should have had a hefty gin and tonic with dinner instead of that glass of wine. And not for the gin, either.
What IS a leg cramp, anyway?
A cramp is a sudden involuntary contraction of a muscle, usually calf, sometimes shin. For something that causes no damage, it sure hurts like hell. The spasm may last anywhere from a few seconds to as many as 15 minutes of misery.
What causes leg cramps?
Medicine hasn’t pinned down the precise mechanism for cramp formation, but there’s lots of statistical and circumstantial evidence for various causes. You’re more likely to get a cramp if you’re female, pregnant, over 60, under the blankets, or taking one of a rather long list of medicines.
Dehydration may or may not be a factor—there’s some controversy here, because people who drink enough liquid can still get cramps. Insufficient magnesium and potassium in the diet are suspects—yet another reason to eat kale and bananas. Lactic acid buildup is a likely villain, so If you’re a runner, you’re more likely to cramp if you didn’t warm up your calf muscles enough before you took off and didn’t stretch them again after you stopped.
What does tonic water have to do with all this?
Tonic water is a word-of-mouth preventative for a pain that can’t be killed by conventional pills. When complaining about leg cramps, I was told by not one but two RN friends to drink tonic water, which contains quinine, an old-school remedy for them.
Quinine comes from the bark of the chinchona tree, a Peruvian native that grows in the sort of places that also favor mosquitoes carrying malaria—the primary target of quinine use. It’s one of those centuries-old superpowers that, like aspirin, give the FDA conniptions.
Quinine flavors tonic water with its love/hate bitter taste that enhances or offsets gin, depending on your point of view. It also shows up in bitter lemon soda and the French aperitif Dubonnet, a favorite quaff of the sort of old lady in vintage British films who either investigates murders or commits them in her cellar.
How does quinine work?
Apparently nobody quite knows, but it seems to relax muscles by diminishing their response to nerve stimulation.
Quinine tablets were a common leg cramp remedy until the U.S. Food and Drug Administration banned over-the-counter use in 1994 and discouraged prescribing it for anything besides malaria (and isn’t entirely happy with that, either). The reason? Quinine can cause fatal seizures as well as stomach distress, diarrhea, headache, vertigo, diminished blood clotting, and irregular heartbeats, among a host of side effects.
Does tonic water actually do anything medicinal?
The quinine in beverages—about 20 milligrams in 8 ounces—is an amount that might be politely described as homeopathic. That doesn’t mean it doesn’t work, though its effects may be primarily placebo.
Tonic water seems to work for me, though I’m hardly a blind study. My control group is my own self when I’ve forgotten to drink it after I run—and my leg cramps at bedtime.
More scientifically, a 2010 British review of 23 randomized controlled trials involving nearly 1,600 crampy folks found that quinine tablets reduced the frequency and intensity of cramps at statistically significant levels.
The killjoys at Harvard Health Publishing say the low concentration of quinine in tonic water shouldn’t be harmful but isn’t likely to prevent cramps. Other physicians do recommend tonic water to runners (along with stretching and bananas).
What if you hate the taste?
Hey, it’s a mixer—mix it with something that offsets that weird bittersweet flavor while supplying some electrolytes, like orange juice.
Or you can always add a splash of Tanqueray.
Among its other attributes, the quinine in tonic water is fluorescent under black light. Credit: Joseph Blosser, CC BY-SA 4.0
The classic mix. Credit: NotFromUtrecht, CC BY-SA 3.0
Stephanie Mumford Brown is Chief Wiseacre at Wiseacre Press, where she’s trying to compile the missing assembly instructions for the second half of life. She's a former reporter/editor, business writer and marketing consultant, now focusing on sportswriting, opinion pieces and books.