Something to try to avoid dehydration?

I dehydrate during long races. Even during marathons. It seems to be a combination of time on my feet and effort and, to a lesser extent temperature and elevation. I usually slow down about mile 18 in a marathon, considerably later in an ultra.

I shall soon be running a ~68 mile race and I’m concerned that if I run it as I’ve run 50 mile races then I’ll end up very sick somewhere around mile 55.

The obvious solution is to drink more. Well, I really can’t in a marathon I already drink at every aid station. But I’ve been trying to do so in my ultras and that hasn’t seemed to help.

Conventional wisdom then says to take salt tablets which are supposed both to increase absorption of water and to help one retain it later. I do that in my ultras. It doesn’t seem to make any difference, except that I get a much denser layer of salt on my skin from sweating.

I’ve been stymied at this point for a while now. But I noticed the other day that just sitting in the shade after the race made me feel better. I drank a little water, but not much (I have vomited after drinking water in the past, so I am cautious), and I don’t think that was what made the difference.

Maybe I overheat and need to cool down? Maybe I’ve got enough water in my stomach but for some reason it doesn’t go into the blood unless I rest.

So I went looking on the web and found an article on problems people have doing Western States 100M. Some people have no problems, but I doubt I’d be one of them. Buried in the midst of problems is the statement:

As you know, running an ultra is stressful on the body….way more stressful than many even think they know it to be. When you place demands on your muscles to keep moving you forward, the blood in your body gets “shunted” to those muscles to fuel them with the oxygen they need to work. And if the muscles are hogging the blood, then some other parts of the body must be sacrificed at the expense of the muscles. Unfortunately, the gut is often sacrificed. And if you keep shoving precious fluids and calories into a gut that cannot absorb them…

and later

Decreasing stress at WS may seem impossible, but there are definitely things you can do. Slowing down or walking is a good place to start. Cooling down if hot is also helpful.

One year when I was in Madagascar a friend of mine was trying to figure out if dominant or subordinate animals were under more stress in a troupe. He did this by collecting feces, storing them in little vials, and taking them back to the States to test for cortisol levels. (Sadly I never got to watch him go through customs.)

So I guess I’m not going to take fecal samples in the middle of a race to test for stress hormones. But let’s presume that I might be getting stressed out and unable to absorb water efficiently.

“Slowing down or walking is a good place to start.” Humph. It was after walking for 3 miles up a steep mountainside in the blazing heat that I started to feel nausea. I was already going slowly or walking. Perhaps sitting down would be even better? (especially in the shade). I think I’ll continue to stress out over the race if I sit/walk/run slowly and see other people passing me. So I think if I truly want to destress I need to take something to distract me from the race — hence the idea of sitting down and pulling out a book for a bit.

Of course sitting down might have its own problems. My legs might stiffen up, so after sitting down for a bit I’d want to start out by walking before I went back to running.

It probably takes a while to relax. Not sure how long, but after my 5:25 run the other day I felt better when Stephanie showed up, which was 16 minutes later. Pausing at an aid station where there’s plenty of water to use for cooling and drinking while I relax is probably a good idea, but I don’t want to waste 15 minutes at every station. Maybe every three hours or so I should take a 15 minute break.

Hoping, of course, that I’d be able to run faster after the break and be able to make up some of the time I lost because of that.

If this works for an ultra, then I wonder if I could do something similar in a marathon? A 15 minute break would be too long… but maybe I could try a 5 minute break somewhere after the halfway point but before mile 18…

Galloway recommends walking during a marathon, but
a) his website doesn’t talk about people who run faster than 8min/mile,
b) he talks of running for 4 minutes and walking for 30 secs which doesn’t seem as if it would address my problems; I think I need a longer rest than that.

I wonder if I might end up taking less time in spite of the break? I wonder if I might avoid feeling nausea?

It’s worth a try.

The idea of racing with a book in my pack is rather appealing.

I feel a bit more motivated now.



(1 March) I finally had a chance to talk to Mike who seemed to feel the general idea of taking a rest was reasonable but questioned the specifics. He said the important thing was to get the heart rate below 100 — at that level blood would flow back to the gut. But he didn’t like the idea of sitting to rest; mostly because it would be hard to start back up again once I stopped. Muscles stiffen, etc. He recommends walking very slowly. Which is actually what everyone else says too, but I did so like the thought of reading a book at an aid station. Ah well.

I wonder where the heart rate of 100 comes from, I haven’t seen that elsewhere… Does that depend on my body or is that really a number that works for everyone?

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3 Responses to “Something to try to avoid dehydration?”

  1. Jon Says:

    I’ve been following a course at Stanford Online about Physiology.
    https://class.stanford.edu/courses/HumanitiesSciences/EP101/Environmental_Physiology/about
    There are many interesting videos. Here are two.
    Exercise in Heat

    Interview with a Badwater competitor

    • georgeruns Says:

      Interesting, but while heat is certainly a contributor to my problem it is not a major factor, as I get the same issues when running in cool temperatures — it just takes longer

  2. Adger Says:

    Sounds like it’s time for some empirical research.

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