"There's only one hard and fast rule in running: sometimes you have to run one hard and fast."

Thursday, March 13, 2008

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Simple, cheap fluid replacement

I want to discuss electrolytes and will probably bore everyone to tears, so I'll start with the most practical thing I'll ever write: how to make your own sports drink.

Pedialyte and other similar products are made specifically for fluid replacement, but are incredibly expensive. Here's how to make exactly the same thing on the cheap. If you ever have a child who's vomiting or has diarrhea, you'll thank me for this.

In a one quart container, add 1/2 teaspoon table salt, 1/2 teaspoon baking soda, 2 tablespoons of sugar and 4 tablespoons of orange juice. The baking soda and orange juice will fizz. Then add water to fill the container. Store in the refrigerator.

Drinking on the run

Before I discuss electrolytes, I have to give practical advice on how much fluid one needs when running. I may not be the person to trust on this, as I severely dehydrated at Voyageur and Leadville last year and overhydrated at FANS.

If you're urinating every two hours and it's clear urine, you're drinking too much. If your urine is dark yellow or you haven't urinated in 5 hours, you're drinking too little. In between, it's more difficult to say. Most people can't tolerate more than a gallon of fluid in 5 hours when running, so that's a starting point for figuring out how much fluid you need in a really long run.

As to what to drink, I recommend starting with the fluid replacement drink as described above. The amount of sodium and potassium are ideal. Then, try adding increasing amounts of sugar. Eventually, you reach a point where you get thirsty during the run, no matter how much you're drinking; this means that the amount of sugar is so high that the osmolality (i.e. concentration) of the solution is keeping it from being absorbed. You want to take in as many calories from the fluid as you can, up to the point where your body can't use it - this, for me, is about 4 tablespoons of sugar per quart. So, increase the amount of sugar in small steps.

Making your own fluid replacement drink is more art than science, more trial and error than engineering. Allan Holtz has a solution that has the advantage of being fairly simple and extremely portable - the sodium and potassium levels are identical to mine: per quart, 1/2 teaspoon salt, 1/2 teaspoon Lite salt (50% table salt, 50% potassium chloride) and 1/3 cup sugar.
That's more sugar than I can tolerate, but it might be perfect for others.

Currently, my solution is, per gallon (NOT quart): 2 teaspoons salt, 2 teaspoons baking soda, 2 teaspoons citric acid (available in home brew shops), 1 teaspoon potassium chloride (salt substitute, available in grocery stores) and 9 ounces of corn syrup (not high fructose corn syrup!). I've made an average of one change per month in the recipe for the past year and a half, so it's a work in progress.

A note on S!Caps

Karl King is very knowledgable and experienced when it comes to electrolytes for ultrarunners and he is extremely helpful to those who ask questions. And he's a chemist and a homebrewer! That said, I have a problem with his product, which has ecome the standard for ultramarathons. Five (this is a correction) gel caps contain 1700 mg. of sodium and 110 mg. of potassium, the same amounts found in one liter of sweat. It's the same amount of sodium as in my replacement drink, per quart, but less potassium. If one dissolved a gel cap in a quart (or liter) of water and ate fruit during the run to replace potassium, it'd be a good idea; unfortunately, the gel cap bypasses your taste buds - you'd have trouble swallowing the salt without it - and you end up with concentrated salt in your stomach if you're not drinking enough fluid, which is often the case in ultras. This leads to nausea and vomiting. Nausea in ultras is common enough, especially in hot weather; why risk it?

The problem with my solution is that it's not something you can easily carry. It has to be mixed ahead of time, or one gets terrible gas. I've experimented with making a slurry/gel of my solution without the water. A gel cap is so simple! And Karl's making a fortune selling table salt!


Kel said...

I seem to do a little better with some Ca and Mg thrown in too. Always done well with Gookinade and Endurolytes (although I'm still kinda new to Endurolytes).

keith said...

You should post this on the Ultralist.

It's good stuff!

bryan said...

Is there a reason for you to include so much potassium? I thought you only need to replace about 1 part K per 18-20 parts Na. (And much lower amounts of Ca and Mg, enough lower that they're not worth worrying about.)

Another option I have just recently tried is Nuun, which comes in a tube of tablets; you drop one tablet into a ~24 oz. bottle of water and two minutes later it is totally dissolved, so you have the portability of caps without the concentration. But, they don't include sugars; I still find it easiest to drink one thing with all the salts and sugars you need.

Carilyn said...

Hey Steve! Great blog - love the info on fluid replacement.

I thought FANS was a great race - tons of support, nice people, good set-up. I've never run KM100, so I'm looking forward to it. I'll keep checking in to see which one you choose :)

Runner Brewer said...

call me crazy..."okay, YOU'RE CRAZY", but I can comfortable consume 1 gallon of fluid in 4 hours. The longest I have to test this is Superior 50 at 11 hours, but I had three 20 oz water bottles from mile 18 until finish. I consumed 1 every half hour.

But, I sweat more than anybody I know. I sweat a lot. My shoes almost always have salt stains on them from my constant sweating. Even in the cold.

Is that distance to short to gage if I was overhydrating? I did not measure the color of my pee on the Lovibond scale, but I think it was clear (or srm of 2-3, I think it also had and IBU of 20, and a SG of 1.054). I think I was going every 2 hours, at least.

How can you tell you are overhydrated (other than what you stated and being hospitalized for hyponatrema)?

SteveQ said...

Wow, I've opened a can of worms! You should see some of the emails.

I'll get into sodium, potassium, calcium, magnesium, etc. soon.

I'm wondering if I should post a rant about all the different products out there. Each works for somebody...

Matt, I almost died laughing thinking about Lovibond scales for urine (anything over 30 would be worrisome, I think). The first sign of overhydration for most people is headache. At FANS, my weight went from 150 at the dinner the night before to 163 when I quit (and I was in the portable toilets all day); that was too much fluid and too much salt.

northwoods bryan said...

Steve: that is a crazy weight gain in one race!

I lost 11 pounds from start to finish of the Twin Cities Marathon last fall. Needless to say I did not have a good handle on hydration at the time.

Since then I've experimented around and settled on a routine of just a 20-ounce bottle of Gatorade per hour of running. Doing this, I've done 20+ mile runs without experiencing any feelings of dehydration and only going down a pound or two at most by the end.