Beware Overhydration (Read 1181 times)

 

MTA: But I like DB's answer better.

I liked his response too, but yours was a billion times more informative. Thanks.

Or, it turns out, any marathoner. I recall that in the same series that bhearn quoted they mentioned that when they look at the hydration levels of elite runners after a marathon very often they find that the most dehydrated athlete is the guy who won the race.

Yeah, that is true, at least going by my recollection of their book, "The Runner's Body". One of the things that struck me about that book is the apparent conflict between this message, in their chapter on hydration, and the message in the chapter on fueling, that you have to take in enough carbs. Yet, you can't absorb carbs without water.

Also, others, e.g. Pfitzinger, assert that a reduction in blood volume will definitely impact performance. Which only stands to reason. If you have less blood to pump to your muscles, you are delivering oxygen at a lower rate. I don't know how to reconcile this with the result mentioned above. One thing is that an elite marathon, at < 2:10, is perhaps a different type of event, physiologically, than a 3 or 4 hour marathon.

Yeah, that is true, at least going by my recollection of their book, "The Runner's Body". One of the things that struck me about that book is the apparent conflict between this message, in their chapter on hydration, and the message in the chapter on fueling, that you have to take in enough carbs. Yet, you can't absorb carbs without water.

 

Also, others, e.g. Pfitzinger, assert that a reduction in blood volume will definitely impact performance. Which only stands to reason. If you have less blood to pump to your muscles, you are delivering oxygen at a lower rate. I don't know how to reconcile this with the result mentioned above. One thing is that an elite marathon, at < 2:10, is perhaps a different type of event, physiologically, than a 3 or 4 hour marathon.

Assuming elite marathon runners maintain a higher blood plasma volume to begin with, they probably have more capacity to "give back" to dehydration before it affects their performance. 

I think we're going to start seeing hyponatremia more and more outside of marathoning.  The fluid pushing is gotten out of control.

The article that Jeff linked is the first in a series, but the SoS guys didn't link them together.

So for you lazybones:

1. The intro (same one that Jeff linked)  Part I: The History of Fluid Intake and Conflict of Interest

2. Part II: Fluid Intake, Dehydration, and Exercise

3. Part III

4. Part IV

5. I think this is Part V, though it isn't labeled as such.  Fluid Intake Debate: Comments from a Doctor

The BAA weigh in.

How does dehydration affect recovery?  Isn't that one component to be kept in mind at least during training?