Passing the Salt

Since my heart attack in 2014, I have been pretty careful about my Sodium intake. What to do during running long distances though, as we lose sodium? According to Matt Fitzgerald, who has written quite a bit on nutrition and sports:

Sodium is said to assist hydration in two ways. First, it's believed to increase the rate of fluid absorption from the gut into the bloodstream. And faster fluid absorption means faster hydration and less dehydration. 

However, according to a pair of studies from the University of Iowa, sodium only increases the rate of fluid absorption if the fluid doesn't also contain carbohydrate. If the fluid doescontain carbohydrate -- as most sports drinks do -- the amount of sodium contained in the drink (or consumed with the drink, in the case of salt tablets) has no effect on the absorption rate. The carbohydrate itself maximizes the rate of fluid absorption. 

The second purported benefit of sodium with regard to hydration is that it helps athletes maintain a higher blood volume, which in turn keeps body temperature and heart rate from rising during prolonged exercise. Research has shown that sodium does indeed have these effects. However, a South African study found that a high-sodium sports drink was no more effective than a low-sodium sports drink in regulating body temperature and preventing "cardiac drift" (rising heart rate during prolonged exercise).

So basically, what I take on a run should do the trick, without any harm. I use Nuun on runs. I swear by it. One tablet contains 320mg of Sodium. I limit my Sodium intake to around 2000mg a day. Since I am sweating out the Sodium on the long runs, I'm not too concerned about what I'm taking at the time, as I know I will lose it. Still I want to be aware of what I am taking in, because the gels or other products I take have Sodium as well.  Now, I am talking about longer runs, by that I mean any run over an hour. Shorter runs don't require me to replace as much as I do during a half marathon. 

I get asked about Salt tablets. I would say if you are someone who is sweating tremendously during runs, and are very worried about cramping, then yes, take those. For most of us though, what we get to electrolyte replacement drinks and sport drinks should be enough.

My rule of thumb of anything you are taking for running or exercise, read the nutritional information, and always ask a doctor what is appropriate if you have concerns.

Charlie