Hydration and Electrolytes

Okay, most everyone out there knows that when you are exercising you sweat. This means that you are losing water and electrolytes (mainly sodium, but others as well). And common sense would dictate that you need to replace what you have lost. So most people will ingest a multitude of different things to accomplish this - water, sports drinks, gels, salt tabs, pretzels, energy bars, etc.

Also, most everyone knows how important it is to make sure you are well hydrated before any exercise - especially an endurance event. You drink gallons of water the days before your event and try and take in a little more salt than usual. This is all done to prepare you for going the distance.

Well, last week I didn't prepare very well and I think it cost me - a toe nail specifically!!

At first I attributed it to the new socks I wore for those 18.5 miles I ran on Saturday. And, yes, I know you shouldn't do anything different for a long run. But I figured the socks were very similar to others I have worn, I should be okay. But when I got home and really examined my left index toe I noticed how raised and white looking it was – the sure signs of a water blister under the nail (I have yet to have a black toe nail).

Just wonderful! I proceeded to take care of the problem so it will heal as quickly as possible before my next long run.

Like I said – I am attributing this all to a new pair of socks.

But the next night a friend was telling me about a book she had thumbed through at REI. It was about taking care of your feet and there was a section regarding black toe nails and electrolyte imbalance.

This is basically what she told me (I copied it from the Internet):

"During your run pay attention to water and electrolyte intake. Dehydration can cause your skin to lose its turgor and the skin layers to separate, causing blisters. An electrolyte imbalance can also contribute to problems. Drinking a sports drink, taking electrolyte capsules and eating salty snacks will help to keep up with sodium loss."

And just in case you are wondering what turgor is:

"Skin turgor is an abnormality in the skin's ability to change shape and return to normal (elasticity). Skin turgor is the skin's degree of resistance to deformation and is determined by various factors, such as the amount of fluids in the body (hydration) and age."

She also told me that once she started training for her IronMan her problems with black toe nails disappeared. And you know why? Because her coach had her taking in more electrolytes and experimenting with salt tabs and such.

Anyway, I had never heard this theory before and tried to find out more about it on the Internet. But, you know what? There isn't really that much out there on it. Most of the stuff is about making sure your shoes (and subsequently your toe box) are big enough and that your nails are clipped short and filed smooth (to prevent snagging on your socks). And when I did find something it was usually in reference to ultra runners. But since I am not very fast I think I need to pay attention since I am usually out there on the course for an extended period of time.

The best article I could find was from an electrolyte replacement web page. Of course, they want you to buy their product, but the information sounded legit. Take a look if you would like to learn more.

http://www.succeedscaps.com/blisters.html

Blisters, Black Toenails and Sodium

Karl King August 7, 2005

The layman thinks it is hard to run an ultra because of the great distances involved - "I get tired just driving that far." Yet foot problems and stomach woes are more threatening to the ultra runner than covering a lot of miles.

Effective digestion requires a sufficient supply of sodium ions. The biochemistry of that is beyond the scope of this forum, so let's focus on the connection between foot problems and sodium.

Consider the typical ultra runner standing at the starting line. The feet are fine, the stomach is fine and the amount of sodium ion in the runner's blood plasma is fine. If those stayed the same during the run, the only factor in finishing would be the runner’s ability to overcome muscle fatigue in the last part of the run.

As the runner proceeds down the course, the body sweats for cooling effect (running generates a lot of un-needed heat that has to be removed from the body). Sweat normally contains the electrolyte ions found in blood plasma. The primary ion in sweat is sodium. Potassium amounts in sweat are considerably lower. Other ions such as calcium, magnesium and iron are present but in very small amounts.

As sodium is lost in sweat, more and more of it is pulled from the blood plasma. There is a normal level of sodium in plasma, and body must maintain the plasma sodium concentration within a tolerable range. If the sodium concentration falls too far outside the range, it can cause death.

As you might suspect, the body has regulation mechanisms to avoid such a catastrophe. If you have too much sodium, thirst increases to prompt drinking water that can dilute or flush away any extra sodium. If you have too little sodium, the body must get more sodium or remove water from the blood plasma. This will lead to an increased desire for salty foods. If sodium in not ingested, then an alternative mechanism must be used. Your body can move water from your blood plasma and put it into extra-cellular spaces between tissue cells. That lowers the amount of water in the blood plasma and returns the ratio of sodium to water to an acceptable level.

That’s good for your blood stream, but what about that water sitting out there between the cells? The cells that were compact now have water around them and that means the mechanical strength of the cellular structure is compromised.

What is unfortunate for ultra runners is that the water will collect in the hands and feet because of gravity. It may be alarming to see your hands swell up, but it usually won’t knock you out of an ultra. The big problem is found in the tissues of the feet. As you know from this forum, your feet are complex structures that bear strong and repetitive insult from the hours of running. Life is hard enough for them even when they are not compromised with extra fluid. When the fluid in extra-cellular spaces gets to be significant, mechanical strength is reduced.

The feet swell inside the running shoes, putting extra pressure on the tissues, and those tissues can be rubbed to the point of physical damage. We see blisters form as layers of skin separate, and we see toenails move more, damaging the weakened tissues that normally anchor them.

If one is not aware of the part electrolyte status plays in tissue strength, it is tempting to blame the socks and/or running shoes. Now, if these give you problems on short runs, the blame is well founded. If you run four consecutive runs that total 40 miles, and the shoe/sock combination works fine, but a single run of 40 miles produces problems, maybe something else is going on. Another tip-off is related to temperature while running.

If your feet do just fine in cold weather, but have problems in hot weather, it could well be a symptom of poor electrolyte status. Runners sweat less in the cold, and sodium is not quickly lost. When the temperatures climb, sweat rate increases and the loss of too much sodium causes problems at a shorter distance than in the cold. Runners in cold northern climates rarely have blister problems during cold long runs, but can have blisters arrive during longs runs when the first hot days of spring arrive.

In my personal experience, electrolyte status made a big difference in the frequency of black toenails. Before I made my own electrolyte supplement, I had six to eight black toenails on a regular basis, just like many of my ultra-running friends. When I got the hang of how to use the supplements, my black toenails gradually healed and I ran ultras for five years with no more toenail problems. I made no significant change in shoe or sock type. In terms of terrain, I actually ran more difficult terrain over those five years.

Sodium intake can be on a hit-or-miss basis, taking whatever might be salty from the aid tables, or it can be controlled by taking a supplement. I developed SUCCEED! Buffered Electrolyte Caps (S! Caps), with 341 mg of sodium per capsule so I would know exactly how much sodium I was getting throughout a run. While individual results vary, low-sodium problems can be avoided by taking one capsule per hour, with water. Since I've used them, blisters and black toenails problems are a thing of the past.

Copyright 1999 Karl King, all rights reserved.