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19-04.-2008, 04:00 AM
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#1 |
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Registered User
Join Date: Dec 2006
Location: Seattle, WA/Vancouver BC
Posts: 296
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Physiological adaptations and dehydration
Curious as to thoughts on the above. Is there a training benefit to riding without proper fluid intake? My quick answer is 'yes' that my leg muscles and heart will make the necessary adaptations to function competently in this dehydrated state (higher heartrate for effort, less efficient lactic acid flushing, decreased efficiency of muscle contractions due to electrolyte loss, etc...). My thinking is that these adaptations will only serve to assist me when the going gets tough in a road race and I haven't properly hydrated before or during. Sort of like riding without eating sufficiently and requiring the muscles to utilize fat as opposed to glycogen predominantly for fuel.
Opinions solicited as to whether or not this is a worthwhile endeavor...thanks... |
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19-04.-2008, 04:37 AM
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#2 |
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Registered User
Join Date: Sep 2005
Posts: 619
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Re: Physiological adaptations and dehydration
No.
Imagine trying to 'not breathe' while training so that when you do breathe, you can super-compensate. |
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19-04.-2008, 05:12 AM
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#3 | |
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Registered User
Join Date: Dec 2006
Location: Seattle, WA/Vancouver BC
Posts: 296
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Re: Physiological adaptations and dehydration
Quote:
Last edited by tonyzackery : 19-04.-2008 at 05:18 AM. |
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19-04.-2008, 05:34 AM
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#4 | |
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Registered User
Join Date: Oct 2006
Posts: 1,311
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Re: Physiological adaptations and dehydration
Quote:
You're right to some extent, you really can't and shouldn't try to stay net even on water intake vs. losses and you'll generally end up at least mildly dehydrated after a long or hot ride. But don't make matters worse by intentionally riding without fluid intake. -Dave |
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19-04.-2008, 06:10 AM
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#5 |
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Registered User
Join Date: Oct 2004
Posts: 1,156
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Re: Physiological adaptations and dehydration
The following is a blog link written by two phd's that I have found to be helpful on the subject.
If you are interested scroll down a little and on the right side you will see a series of links under "Read our popular series on dehydration:" The Science of Sport
__________________
My Blog |
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19-04.-2008, 06:28 AM
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#6 | |
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Registered User
Join Date: Dec 2006
Location: Seattle, WA/Vancouver BC
Posts: 296
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Re: Physiological adaptations and dehydration
Quote:
Your opinions and insight in these forums is well respected. Thanks for sharing. However, don't get me wrong here: I'm not about to embark on a 4 hour ride in 80+ degree heat, or even advocating such lunacy. I have to think that I'm just a little smarter than that...Anyway, I was enquiring about the potential for physiological training adaptation to riding without fluid intake, or purposely under hydrating for periodic rides up to, say, a couple hours or so - not riding while severely dehydrated. I was looking for opinion as to whether training in this manner could create a desirable adaptation to be utilized if and when I get mildly dehydrated during a race. |
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19-04.-2008, 06:31 AM
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#7 | |
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Registered User
Join Date: Dec 2006
Location: Seattle, WA/Vancouver BC
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Re: Physiological adaptations and dehydration
Quote:
Excellent info! Thank you! |
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19-04.-2008, 07:14 AM
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#8 | |
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Registered User
Join Date: Oct 2007
Posts: 88
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Re: Physiological adaptations and dehydration
Quote:
Excellent information. Thanks for sharing!. Tim Noakes was his Doctorate director. Dr. Noakes is one of the worlds´s leading authorities in exercise and hydration. Cheers |
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19-04.-2008, 09:15 AM
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#9 | |
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Registered User
Join Date: Jul 2003
Posts: 2,543
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Re: Physiological adaptations and dehydration
Quote:
Ron Maughan would take exception to that statement.  |
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19-04.-2008, 10:11 AM
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#10 | |
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Registered User
Join Date: Apr 2005
Location: Kansas City, USA
Posts: 3,534
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Re: Physiological adaptations and dehydration
Quote:
I don't see anything wrong with a 4hr ride in 80+ degree (Fahrenheit, right?  ) heat, but just so there's no further misinterpretation of your question, what exactly are you advocating? Another question is, if you can control for mild dehydration during your rides, how about just maintaining proper hydration during races instead?If your question really boils down to: "should I drink during training about the same as I drink while racing?" then intuitively I would say "yes." However, your question seems (to me) to propose drinking less during training than during racing. |
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19-04.-2008, 10:28 AM
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#11 | |
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Registered User
Join Date: Oct 2006
Posts: 1,311
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Re: Physiological adaptations and dehydration
Quote:
FWIW I've been an EMT, ski patroller and mountaineering guide for more than a decade. I've seen many cases of dehydration in the mountains many which required technical evacuation as the patients could no longer walk out under their own power. I've also seen a few documented cases of hyponatremia which has similar results and is just as dangerous but a lot less common. Your idea of training on intentionally restricted water is similar to suggestions that you should go on training rides without fueling yourself. They're both bad ideas but at least you'll generally get home in one piece if you bonk on a ride. Dehydration hits you a lot faster and unlike glycogen you can't just drop back to your stored fat when you run low on water, you just run out of fluids, overheat and shut down. Here's some published thoughts on the subject: http://www.ncbi.nlm.nih.gov/pubmed/16558633?ordinalpos=13&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum http://www.ncbi.nlm.nih.gov/pubmed/...ry_RA&linkpos=2 http://www.ncbi.nlm.nih.gov/pubmed/...ry_RA&linkpos=4 http://www.ncbi.nlm.nih.gov/pubmed/17909410?ordinalpos=11&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum http://www.ncbi.nlm.nih.gov/pubmed/...ry_RA&linkpos=1 http://www.ncbi.nlm.nih.gov/pubmed/17618000?ordinalpos=4&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum http://www.ncbi.nlm.nih.gov/pubmed/...ry_RA&linkpos=5 http://www.ncbi.nlm.nih.gov/pubmed/12457417?ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum ftp://ftp.cdc.gov/pub/Publications/mmwr/wk/mm4706.pdf http://www.fitness-nutrition-weight...ydrate-now.html Good luck, -Dave |
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19-04.-2008, 10:34 AM
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#12 | |
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Registered User
Join Date: Apr 2005
Location: Kansas City, USA
Posts: 3,534
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Re: Physiological adaptations and dehydration
Quote:
Good articles. Anybody picked up the new Polar core temperature sensor add-on for performance optimization yet?  |
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19-04.-2008, 10:40 AM
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#13 | |
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Registered User
Join Date: Dec 2006
Location: Seattle, WA/Vancouver BC
Posts: 296
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Re: Physiological adaptations and dehydration
Quote:
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. |
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19-04.-2008, 10:48 AM
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#14 | |
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Registered User
Join Date: Oct 2006
Posts: 1,311
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Re: Physiological adaptations and dehydration
Quote:
http://www.hammernutrition.com/za/H...formance%20Tips FWIW they agree with your statement above, you'll generally finish a race somewhat dehydrated and according to them you really shouldn't try to replace all your lost fluids as you ride. But that's not the same as advocating training in an intentionally dehydrated state in hopes of a positive adaptation to that state. |
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19-04.-2008, 11:18 AM
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#15 | |
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Registered User
Join Date: Apr 2005
Location: Kansas City, USA
Posts: 3,534
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Re: Physiological adaptations and dehydration
Quote:
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. |
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