Jim2's Running Page

Marathon Cramps - 2

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If you have found a regimen to avoid cramps during a marathon that works for you, stick with it. Don't listen to the "naysayers" who try to tell you that you are doing something wrong or unnecessary.


I found a regimen that stopped my marathon cramps after suffering them in several races. It wasn't simply one "silver bullet". But a combination of factors.


I believe that the primary cause of cramps during a marathon is over running it.....trying to run a pace that you truly aren't prepared for. Obviously, the solution(s) for that is (are) more intensive training and/or better race planning and/or execution.


However, assuming that you are adequately trained for your race plan and that you execute your plan properly, then I also believe that there are other factors that come into play, especially when you are running "on the edge". These "other factors" include your potassium and sodium stores going into the race and the intake of electrolytes during the race.


There is a lot of controversy concerning the benefit of potassium or sodium loading or loss in marathoning. Some "studies" indicate that it doesn’t appear to be a factor. However, none are conclusive, in my opinion. I am a believer in and an advocate of potassium, not sodium, loading. However, is sodium also important? Absolutely!


I do agree that the loss and replenishment of sodium is important during the race, despite "studies" that have indicated that they are "minimal". This is especially important if you are taking in a lot of water during a race, as you should do. The combination of sodium loss and water intake can lead to hyponathermia if the balance of sodium and water gets too far out of balance.....which can result in cramps and, in extreme circumstances, can even be fatal.


However, prerace "protection" against hyponathermia isn't to load up on sodium, but to potassium load. Why? For three reasons. (1) I believe that "average" Americans, including marathoners, get more than enough sodium and not enough potassium in a typical American diet. (There can be exceptions....check your diet!) (2) Potassium, not sodium, is stored in muscles along with glycogen while carbo loading prior to a marathon. And, finally, (3) these "extra" potassium stores are expended during the race in lieu of sodium stores as glycogen is depleted. Thus, the value of potassium loading before a marathon is to conserve sodium stores during the race, which helps to maintain a proper sodium/hydration balance and prevent hyponathermia.....and muscle cramps.


For a lot more detail and explanation, see two old posts of mine titled "Marathon Cramps" and "Sodium vs. Potassium" on my Running Page.