Exercise Associated Muscle Cramping – Intervention and Prevention,
Since there’s decades of misunderstanding and misinformation around this and still lots we don’t know, I’d like to cover a few of the ‘truths’ and ‘untruths’ of EAMC. One of the enduring aspects of EAMC is that there simply is so much that hasn’t been proven and so much we still don’t know. The following digest is a summary on exploration of the field and unfortunately the prevalence of the word ‘probably’ highlights our lack of comprehensive understanding on the topic.
What causes EAMC,
THERE IS NO CLEAR CAUSE FOR EAMC. We simply do not know what causes it. We have studied many mechanisms however empirical evidence is lacking. EAMC is most probably a culmination of several factors like heat, dehydration and neuromuscular fatigue. None may be isolated as the true singular cause as EAMC will endure in the absence of that factor. For example, if heat alone caused cramping, why then can people cramp in cold conditions? Similarly, well hydrated people may cramp, as may many without neuromuscular fatigue (night cramps etc).
Beyond ‘science’ and research EAMC can be explored by the fields of philosophy and psychology. And why not? It was philosophers that first suggested the earth was round and that it revolved around the sun long before conventional mathematics or science was able to prove it so. You could argue that philosophy is the cornerstone of hypothesis – if this, then what? – which is the driver for all scientific research.
With so much unknown about EAMC, what contribution has psychology had? Surprisingly plenty. Professor Tim Noakes cited elsewhere below for his contributions to ‘Waterlogged’, has worked tirelessly to promote his ‘theory’ of the ‘central governor’. A subconscious process in our brain which determines how hard to work in exercise and you’ve probably heard me use the term “the brain is an excellent self-preservation tool”. The central governor is the silent limiter and EAMC is ‘probably’ linked to a panic response within the brain to stop exercise. More on this in the section ‘Intervention’ below. The trick may be to prevent this panic response by ensuring sufficient training has been undertaken to sustain the exercise, or the effort associated to the exercise is reduced given environmental factors associated to effort such as heat. Slowing down will probably reduce cramping (no duh). Training more will probably reduce the likelihood of cramping (you don’t say). The central governor theory is an exciting frontier and the minds role in sports performance is likely the greatest area for future exploration.
The central governor’s role in fatigue explained here – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4854881/
The role of Magnesium (Mg),
Mg is part of the ATP process and is required for movement. Its absence will most certainly lead to cramping. It is stored in within the mitochondria and is built up gradually over days or weeks. It is normally sufficient in our diets provided we eat a modest amount of green things. It can be lacking in some diets or used at a rate greater than it is ingested and stored in which case daily Mg supplements help buffer this store. Appreciate that the process of maintaining or storing Mg is a slow one and you can’t consume Mg and access it gastrointestinal. Remember it’s stored within the cells. As a dietry supplement it is quite safe since your body simply sheds excess Mg in body waste.
There is no evidence to suggest that Mg as any effect on cramping in sport – https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0048475/
A precautionary note here is that further to it not serving any purpose if ingested is that Mg is the primary active ingredient in laxatives. DON’T CONSUME MAGNESIUM ON RACE DAY.
The role of Potassium (K),
Similar to Mg, K is required in the muscle contraction process but for not plain reason Potassium hasn’t become a ‘popular’ homeopathy prevention or intervention strategy.
Like Mg, K has no clear association with EAMC in ultra runners – https://www.ncbi.nlm.nih.gov/pubmed/15273192 and no evidence that K levels change in Ironman athletes – https://www.ncbi.nlm.nih.gov/pubmed/16015122
The role of Sodium (Na),
Perhaps the biggest and most enduring misunderstanding around cramping is the role of Sodium. Sodium and Chloride (Cl-) are the two electrolytes we find in our sweat. Like Mg and K, for some reason people focus mainly on Na and ignore Cl-. Ultra-runners are seldom found popping Cl- pills which is a good thing since, like Na, there’s not a lot of evidence supporting Chlorides role in EAMC.
When we exercise – we sweat. The content of our sweat has been exhaustively examined and measured.
The assumed logic we are quick to adopt is that if something is coming out of us we have to put it back in or suffer some sort of consequence. The assumed consequence is EAMC however there’s no evidence to support this. We know for certain that sweat is MOSTLY WATER, with a small amount of Na and Cl-, and infinitesimal quantities of Mg and K. If we are losing more water than we are anything else (Na, Cl-, Mg, K) then as the volume of water in our blood plasma decreases, the relative levels of Na, Cl-, Mg and K INCREASES. If you measure these quantities within our blood after exercise you will actually find that as a ratio to water they have increased.
Your kidneys are constantly trying to balance Na levels relative to water levels but it’s the water levels that matter here, not the Na. The trick may be to help your kidneys ‘balancing function’ by ensuring there is some sodium in the fluid we ingest during exercise. More likely, is that SOME (not all) EAMC may be a result of the body’s warning sign regarding imbalances in sodium and water levels but to clarify, this is probably a function of water, not sodium. The amount of sodium being ingested is typically very small indeed. What you’re drinking is almost entirely water. Drink water plus a tiny amount of electrolytes.
In the same way low levels of Na may or may not be related cramping, high levels of Na may or may not be related cramping. The safest bet is probably NOT to ingest masses of Na during exercise. Once again, there is no evidence to suggest that ingesting salt will reduce EAMC. It most certainly will mess with your kidneys ability to balance sodium and water levels in your blood. Just because salt is coming out of you, you don’t need to be putting it back in you.
Further reading on EAMC, Cramping and PREVENTION
Worth a read!
Meta Analysis and summary of scholarly articles pertaining to EAMC – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445088/
Accurate lay interpretation of peer reviewed, accepted science and fact –
Intervention (Bold, ,underline, all caps) is about stopping EAMC at onset. Not preventing it from occurring. Once you have cramp, what then?
It seems a salty, bitter, spicy (or similar) mouth wash will probably stop cramping at onset. A study in 2010 showed that ingested pickle juice was quick to alleviate electrically induced muscle cramps – https://www.ncbi.nlm.nih.gov/pubmed/19997012 Anecdotal testing has shown that it is probably the taste alone that is stopping the cramping. It is probably a ‘short-circuit’ of the neuromuscular signal causing the EAMC that results in its caseation. There are now plenty of products on the market that are harmless and worth experimenting with yourself. Remember to spit, not swallow.
Lastly, stretching at onset will help combat EAMC.