tonyzackery said:
My question is as stated afore: Is there any potential benefit to racing performance in purposely underhydrating while training (within reason)?
IMO, it is frequently easier said than done to maintain "proper" hydration during a race. This explains why frequently racers lose significant amounts of water weight during races. Exactly what is the proper hydration level for a given athlete is up for significant debate pursuant to the information provided in the link above from Felt Rider.
I think it's difficult for an exercising athlete to know what their hydration level is at all. I think that means I'm agreeing with what you're saying about hydration during racing, but also means I'm skeptical about one's ability to control for hydration levels below that found during racing, but above the performance degrading levels.
Regarding the articles (and these comments are no longer directed toward Tonyzackery): The more I think about them the less satisfaction I'm really left with. They seem to reasonably refute the idea of "drink all you can" if that ever was really a serious approach, but they don't add a lot of useful information.
For example, from the articles we know that:
1) core temp is naturally regulated in an elevated band during exercise
2) weight loss during exercise is common during competition
3) over-hydration is possible and dangerous
4) heat-exhaustion and related serious effects sometimes, but don't always, involve dehydration
5) if core-temp regulation becomes difficult, the body responds by reducing metabolic intensity (ie, your race/training is essentially over)
It seems like the articles are using very few dots and very long lines to draw the picture, however. For example:
1) Regarding #4 above, since evaporative fluid loss is the chief method of temperature regulation, what
is the most common factor in heat exhaustion during exercise if not dehydration?
2) what amount of fluid loss can be tolerated before there is a measurable reduction in "performance" (metabolic output, muscle coordination, mental concentration, etc.)?
3) IME while exercising in extreme heat, thirst is drastically reduced as the heat-exhaustion symptoms begin to creep in. That would seem to create a slippery slope in the 'drinking to thirst' approach to hydration.
4) #5 above is great with regards to core-temp regulation, but that seems to agree with the "loss of performance" worry that the sports drink ads refer to.
Good, objective food for thought in any case, but they seem to punch holes in some things without presenting any ideas to fill them in with.
