Will I run dry?

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Will I run dry?

Postby webclaus » Tue Aug 31, 2010 12:33 pm

Hi folks,

I just completed a 100k run on nothing but Perpetuem, endurolytes and water - what a great feeling not having any stomach problems at all - I'm convinced :)

I kept fluid intake below 500ml per hour and since the day was relatively cold there were no problems with this.

However, I do have a simple question (maybe answered elsewhere but I haven't been able to find an answer): If I end up in a really hot race and start sweating two or maybe three liters per hour, how am I going to cope if I have to restrict myself to less than a liter of fluid intake per hour? My math is challenged here :o)
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Re: Will I run dry?

Postby steve-born » Thu Sep 02, 2010 1:08 pm

Hello webclaus -

First, congratulations on the successful completion of your 100k run and for the positive feedback on the Hammer products and how they worked for you.

As far as your hot-weather race is concerned, chances are you will be losing large amounts of fluids at the onset of the race (sodium and other minerals as well). However, the body has a number of built-in mechanisms that help protect it and help bridge the gap between what it's losing and what it can comfortably accept in return from you.

Remember, your body is not equipped to replenish its fluid losses in equal to near-equal amounts from your exogenous donation. Ditto for calories and electrolytes as well. Dr. Bill Misner writes, "To suggest that fluids, sodium, and fuels-induced glycogen replenishment can happen at the same rate as it is spent during exercise is simply not true. Endurance exercise beyond 1-2 hours is a deficit spending entity, with proportionate return or replenishment always in arrears. The endurance exercise outcome is to postpone fatigue, not to replace all the fuel, fluids, and electrolytes lost during the event. It can’t be done, though many of us have tried."

"The human body has so many survival safeguards by which it regulates living one more minute, that when we try too hard to fulfill all its needs we interfere, doing more harm than good."

-- END --

Look at the one section again where it states that the goal of fueling is not to replace all of the calories, fluids, and electrolytes that one is losing... the body is simply not equipped to do so. The goal of fueling is to postpone fatigue for as long as possible.

In a hot-weather race yes, you will need more than 500 ml of fluid an hour and it wouldn't be out of the question to consume upwards of double that or even slightly more. Just remember that your body's fluid losses will be monitored closely by hormonal mechanisms (think "survival mechanisms") during the race and that it will recirculate as much of its stores of fluid back into the blood via the kidneys (ditto for sodium and other electrolytes). In other words, your body does recognize that it can't accept from your donation an amount that comes anywhere near its losses.

Now, it can't go on forever like this; you will have to consume fluid to maintain as optimal hydration status as possible. However, if you try to replace all of the fluids you may be losing milliliter for milliliter you will be flirting with over-hydration and all of the problems (name hyponatremia) that exist with that.

My recommendation is that you pace yourself in deference to the weather... remember, in hot-weather conditions it can't be "business as usual" when it comes to your pace (you may have to slow it down a bit to accommodate the hot temperatures). Second, increase your fluid intake gradually so that, if necessary, you're consuming upwards of a maximum 900-1000 ml/hour. Third, increase your Endurolytes intake to match your increased fluid intake. Do those three things and you will have the best opportunity for success in a hot weather race.

I hope this helps.

Sincerely -

Steve Born
Fueling Expert
Event Sponsorship Coordinator
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Re: Will I run dry?

Postby PowerGoat » Sun Sep 12, 2010 2:03 pm

Hello Webclaus,

Congrats on the 100k. Which race was it? Were you happy with how you felt during the run?

As you learned, Perpetuem, Endurolytes, and water are about all you need to make it 100k in pretty reasonable shape. I'll let you in on a secret: you'll be able to hit 100 miles, and 24 hours, and even farther on just these three things also. As long as YOU run intelligently, the Perpetuem and Endurolytes will be enough to keep you going. So, you must have done a smart job of evaluating yourself all throughout the day. Good work.

As Steve was saying, the hot weather asks different things of you. For example, you may still need the same amount of Perpetuem per hour, but might need more water and more Endurolytes per hour. 500 ml is about 17 ounces, so I'd suggest--and this really depends on you, your pace, your weight, etc.--thinking about a range more like 25-30 ounces or so per that's about 750-850 ml, give or take. Really though, it's not so much what Steve or I say, it's about what your body says. If you try 850 ounces per hour and barf three times halfway through the first hour, you should back off because your body isn't handling it well. It's really all about adjusting, and with months and months of stinky cold weather before the good weather comes back, you'll have a lot of time to get used to it and to practice it.

Congrats again on your success.

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Re: Will I run dry?

Postby webclaus » Thu Sep 16, 2010 6:25 am

To both of you guys, thanks much for the elaborate answers.

I read the fueling handbook from a-z, which was what got me into trying the Hammer products in the first place. I have had so many stomach problems lately that I decided it was time to try something new, and without having the time to test it, I simply followed the average recommendations, sort of. I ended up consuming some 220 kcal per hour and some 400ml of water to go along with it (used the multihour bottle approach and carried a hydration vest). It was not a warm day and we had some rain, so it worked out fine. As for endurolytes I took one every half hour for each of the 10 hours of the race.

I live en Denmark and the race was an "around the island" on one of hour small islands here.

I'm looking forward to testing the perpetuem/endurolyte combo in even longer races as get more into ultras (only done two 100k races so far), and I am exactly expecting that it will carry me a lot further. Though chocolate looks tempting at those late in the day aid stations I'm pretty good at sticking with my plan, so I think I could be ok with using only perpetuem for, say, a 24hour race, which I have scheduled in the spring. I'll keep you posted on that one :o)

The reason at all for bringing the hydration issue up was that I of course have desert run ambitions and I'm a heavy sweater already as it is, so I just couldn't make the math add up if I'm loosing 2-3 liters per hour and at the same time must stick to taking in no more than 1 liter.

Anyone with desert run experience like to chip in with some cold facts on how their numbers have looked during extremely hot races?
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