“The belief in the association between cramping and sodium deficit came from a study nearly a hundred years ago, involving British mine workers. Mine owners and scientists were curious about the cause of muscle cramping in miners, so they conducted a study examining cramping miners and the sodium content of their body secretions: sweat and urine. Based on this single study, the belief that cramps were caused by low sodium was born. And, in the 1960s, scientists jumped on this nugget and ran with it.
The study was tragically flawed: insufficient subjects, a lack of controls, and – most outrageously – completely failed to show any correlation between cramping and sodium. Instead, they found a single subject with low sodium in his urine. That’s it. Thus, our belief of salt and cramping originated from a urine sodium sample of a single study, of a single miner… who did not even experience muscle cramping!
This finding lay dormant, until the 1960s. The history of Gatorade and performance is well-documented in Waterlogged, and described in detail in last August’s column. Because of several confounding factors (ad libitum hydration, sugar intake, and placebo effect, to name a few), the belief that salt benefits performance ran roughshod through the athletic community.
Today, that belief is nearly unshakable.
Let’s review what we know (or think we know, or know what we don’t know) so far:
- Muscle cramping is a neurological, “electrical” phenomenon, likely centered in the central nervous system, where reflexes become unbalanced, affecting the muscle.
- The muscle is most susceptible to cramping with prolonged fatigue and (according to Noakes), when we “run faster than we should.”
- Sodium or electrolyte balance – in the blood stream or muscle cell – has zero effect on cramping.
- Sodium (and possibly water, sugar, and fat) tasting in the mouth (and possibly upper GI tract) does have a positive effect: dampening cramping and improving performance. But the rapidity of this effect suggests that it is the brain alone that creates this effect.
- Muscles most affected by cramping are those repetitively used and confined to a small arc of motion.
- The only known treatments to cramping are to slow down, stop, and stretch the muscle to a maximally lengthened state.”