Physiological adaptations and dehydration

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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...

No.

Imagine trying to 'not breathe' while training so that when you do breathe, you can super-compensate.

No.

Imagine trying to 'not breathe' while training so that when you do breathe, you can super-compensate.Thanks for your opinion. Your "explanation" leaves a lot to be desired however...I have an opinion, just my opinion of course, that breathing (or more accurately, the intake of oxygen) is an absolute necessity to competent bodily function...I could be wrong though...

Thanks for your opinion. Your "explanation" leaves a lot to be desired however...I have an opinion, just my opinion of course, that breathing (or more accurately, the intake of oxygen) is an absolute necessity to competent bodily function...I could be wrong though...Yes O2 is a neccessity, as is H2O and electrolytes. You can't train your body to work well while severely dehydrated though many folks have tried over the years. Water is necessary for many reasons, but cooling is one really important reason. Run out of fluids to sweat on a hot day or while working hard and you risk heat exhaustion and worse heat stroke which is literally cooking your brain.

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

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 (http://scienceofsport.blogspot.com/)

Yes O2 is a neccessity, as is H2O and electrolytes. You can't train your body to work well while severely dehydrated though many folks have tried over the years. Water is necessary for many reasons, but cooling is one really important reason. Run out of fluids to sweat on a hot day or while working hard and you risk heat exhaustion and worse heat stroke which is literally cooking your brain.

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
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.

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 (http://scienceofsport.blogspot.com/)
Excellent info! Thank you!

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 (http://scienceofsport.blogspot.com/)
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

Dr. Noakes is one of the worlds´s leading authorities in exercise and hydration.

Ron Maughan would take exception to that statement. ;)

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.
I don't see anything wrong with a 4hr ride in 80+ degree (Fahrenheit, right? :eek: ) 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.

... 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.It's your body to experiment on as you will, but you can't train to ride without fluids any more than you can train to ride without fuels or as spunout suggested, without oxygen. The line between intentional dehydration during training and dangerous dehydration is a fine line to walk. The articles cited above definitely stress the importance of avoiding hyponatremia but no one is suggesting you should intentionally train in a dehydrated state or that your body is capable of adapting to such training.

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/9303999?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2
http://www.ncbi.nlm.nih.gov/pubmed/16558408?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_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/11834105?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_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/16320170?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_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-weightloss.com/change-your-body-today-super-hydrate-now.html

Good luck,
-Dave

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 (http://scienceofsport.blogspot.com/)
Good articles. Anybody picked up the new Polar core temperature sensor add-on for performance optimization yet? :p

I don't see anything wrong with a 4hr ride in 80+ degree (Fahrenheit, right? :eek: ) 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.I was referring to a 4hr ride in 80+ degree fahrenheit heat without any water.

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.

...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.Hammer Nutrition has some good on line articles that discuss this stuff. Here's a good link:
http://www.hammernutrition.com/za/HNT?PAGE=ARTICLE&ARTICLE.ID=299&OMI=&AMI=&RETURN_URL=%2Fza%2FHNT%3FPAGE%3DTRAININGTIPS%26OMI%3D%26AMI%3D&RETURN_TEXT=Performance%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.

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.

... 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.....Agreed, the original research points out problems at either extreme but doesn't help that much in terms of real world hydration strategies. The Hammer Nutrition piece linked above and other stuff on their site and in their printed material gives specific guidelines but you've got to consider the source, their philosophy and perhaps their marketing agenda.

Still I find their advice of limiting your fluid intake to 20 ounces per hour for typical weather conditions with broad based electrolytes (more than just sodium and potassium) to be pretty reasonable. They also strongly push the idea that everything we do nutritionally during training and racing is a deficit game and attempts to consume anything at our burn rate are counterproductive. IOW, you will eventually run out of glycogen and you will eventually become dehydrated and you'll eventually run out of electrolytes the trick is to delay those problems as long as possible, get to the finish line and then replenish post event.

They make a pretty good argument for their approach and it holds up with other references like Monique Ryan's work (no relation), Dan Bernadot's "Advanced Sports Nutrition", Suzanne Eberle's "Endurance Sports Nutrition", etc. It also holds up pretty well with what's reasonable during races, 200-300 Calories per hour, 20 ounces of fluid per hour, those are typically what I can manage during hard racing or training.

But I agree, read too many studies and it's hard to know what to do....

-Dave

2) what amount of fluid loss can be tolerated before there is a measurable reduction in "performance" (metabolic output, muscle coordination, mental concentration, etc.)?

Based on work from Coyle's lab, the answer appears to be "none".

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....
Come down here (near sunny Sacramento, CA) and we can go for a 4 hour ride around Lake Berryessa and take in the big hills and get about 5000ft of climbingin during mid June/July when it's around 100F.... If you're wiser than the average bear you get up at 5.30am when its 'only' in the mid 70's and get back when the heat starts to kick in.

But... you can ride in that heat, some of us have no choice. At that time of year the Profile Design behind the seat dual water bottle doohicky comes out and I take 4 bottles with me....

I dig the Hammer Nutrition products. They seem to work well for me and don't taste to bad either. If only they sold the Science in Sport drinks here in the US. That stuff was great.... UK only though it would seem.

Good articles. Anybody picked up the new Polar core temperature sensor add-on for performance optimization yet? :p
Reminds me of a joke: What is the difference between an oral and an anal thermometer?

Reminds me of a joke: What is the difference between an oral and an anal thermometer?
I'm afraid to ask. What?