/ Hydration - Interesting Reading !

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Nath93 - on 01 Aug 2012
http://www.irunfar.com/2012/07/waterlogged-a-dogma-shattering-book.html

Very interesting stuff, worth a look if you haven't seen it yet !
Eric9Points - on 01 Aug 2012
In reply to Nath93:

Just read the first dozen paragraphs or so but isn't this bloke just saying you shouldn't drink too much and use thirst as a guide?

Sounds eminently sensible to me.
Steve John B - on 01 Aug 2012
In reply to Nath93: There's a chapter on this in "Brain Training for Runners" (excellent book)
Indy - on 07 Aug 2012
In reply to Eric9Points:

I think that this says it much better. Its long but fascinating.

http://www.bmj.com/content/345/bmj.e4737
highclimber - on 07 Aug 2012
In reply to Nath93: anyone who tells you you should be drinking X amount of glasses of water per day deserves a smack. it's a perfectly sensible idea to only drink when you're thirsty - that's what thirst is!
Ben Sharp - on 07 Aug 2012
In reply to highclimber:
> (In reply to Nath93) anyone who tells you you should be drinking X amount of glasses of water per day deserves a smack. it's a perfectly sensible idea to only drink when you're thirsty - that's what thirst is!

Exactly, and if you're body tells you it fancies a beer you've just got to listen to it. It knows what it's doing.
DancingOnRock - on 08 Aug 2012
In reply to Nath93: Excellent piece. Kept crashing my phone, but have now read it on my PC.

Lots of myths busted and more questions raised. Some good comments and replies at the bottom too. I ran 13miles on Sunday in 2h15 with no water. Was pretty thirsty at the end but didn't die of dehydration or cramp up etc.
Tobias at Home - on 08 Aug 2012
In reply to highclimber:
> it's a perfectly sensible idea to only drink when you're thirsty - that's what thirst is!

not sure it is as cut and dry as that. there's a lag between thirst and having lost some water. water takes time to be absorbed so waiting for thirst isn't going to be the optimum way to hydrate.
ThunderCat - on 08 Aug 2012
In reply to Tobias at Home:

Saw something similar on a recent Horizon. Advice about 'staying ahead of your thirst' tend to be touted by (surprise surprise) water manufacturers.

Same as sports / isotonic drinks giving you the performance edge.

And £200 trainers improving your running and chance of injury.

Utter bollocks.

Use the body as a guide. It's had a couple of thousand years to develop and hone the nack of telling you when you need water, and it doesn't have a vested financial interest in making you drink more than you need.
Tobias at Home - on 08 Aug 2012
In reply to ThunderCat: so your body can anticipate the amount of water you need to drink now to replace the fluid you lose in the next 30mins? that doesn't make sense to me!

ThunderCat - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to ThunderCat) so your body can anticipate the amount of water you need to drink now to replace the fluid you lose in the next 30mins? that doesn't make sense to me!

That's not what I said. Your body tells you how much it needs 'now'. It's called being thirsty. The mechanism has stood every living organism in pretty good for many many many thousands of years.

I can see why food might need to be stored as fat in advance of harsh conditions but water doesn't work like that.

Unless your a camel... :)



ThunderCat - on 08 Aug 2012
In reply to ThunderCat:

Anyhoo, here's a link to the program. It was quite good. And it was Panorama, not Horizon...

http://www.bbc.co.uk/iplayer/episode/b01l1yxk/Panorama_The_Truth_About_Sports_Products/

Tobias at Home - on 08 Aug 2012
In reply to ThunderCat:
> (In reply to Tobias at Home)
> [...]
>
> That's not what I said. Your body tells you how much it needs 'now'. It's called being thirsty. The mechanism has stood every living organism in pretty good for many many many thousands of years.
>
> I can see why food might need to be stored as fat in advance of harsh conditions but water doesn't work like that.
>
> Unless your a camel... :)

but that's my point - if your doing exercise, you are using water at a particular rate. there is a lag in how long it takes for your body to absorb new water - waiting until you need that water because you are thirsty is silly.

fine, drink when you're thirsty whilst sedentary but not anticipating thirst whilst exercising makes no sense.

similarly, you should eat before you are hungry too!

mkean - on 08 Aug 2012
In reply to ThunderCat:
http://www.bbc.co.uk/iplayer/episode/b01l1yxk/Panorama_The_Truth_About_Sports_Products/

Some interesting selective editting there and I'm pretty sure I spotted a few factual errors when they were talking about fatalities. Panorama is not my first choice for high quality and impartial reporting.

ThunderCat - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to ThunderCat)
> [...]
>

> similarly, you should eat before you are hungry too!


No. You shouldn't.

galpinos - on 08 Aug 2012
In reply to Tobias at Home:

To quote the BMJ article, "the body has a perfectly good homeostatic mechanism for detecting and responding to dehydration—thirst."

Why does trying to drink before you are thirsty help you in any way during exercise?
ThunderCat - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to ThunderCat)
> [...]
>
>
> similarly, you should eat before you are hungry too!

Eat when you are hungry, and only when you're hungry. Stop when you cease being hungry.
ThunderCat - on 08 Aug 2012
In reply to galpinos:
> (In reply to Tobias at Home)
>
> To quote the BMJ article, "the body has a perfectly good homeostatic mechanism for detecting and responding to dehydration—thirst."

See, that's what I meant. But when I tried to say it, I came across sounding like a patronising tw*t. I apologise, that's not how I meant it to sound.
Tobias at Home - on 08 Aug 2012
In reply to galpinos:
> (In reply to Tobias at Home)
>
> To quote the BMJ article, "the body has a perfectly good homeostatic mechanism for detecting and responding to dehydration—thirst."
>
> Why does trying to drink before you are thirsty help you in any way during exercise?

because the body can only respond to its hydration level at that moment - it can't anticipate the fluid you will be losing in the next 30min - therefore, it makes sense to be drinking before you get thirsty during exercise.
Tobias at Home - on 08 Aug 2012
In reply to ThunderCat:
> (In reply to galpinos)
> [...]
>
> See, that's what I meant. But when I tried to say it, I came across sounding like a patronising tw*t. I apologise, that's not how I meant it to sound.

:-) i didn't feel patronised - i think we are talking two different points - i'm all for listening to the body for what it needs - i just think when exercising i know better about what i'll need over the next 30mins than my body's hunger and thirst sensations.
DancingOnRock - on 08 Aug 2012
In reply to Tobias at Home: Have a good read. It's not just thirst that regulates your hydration/salt balance. There are ADT hormones etc that regulate the amount of salt you excrete during sweating and the amount of water you urinate.
galpinos - on 08 Aug 2012
In reply to ThunderCat:
> (In reply to galpinos)
> [...]
>
> See, that's what I meant. But when I tried to say it, I came across sounding like a patronising tw*t. I apologise, that's not how I meant it to sound.

I believe it's a quote from Tim Noakes so I'd hope it was succinct!
ajsteele - on 08 Aug 2012
In reply to galpinos:

Simply because it takes a while for your body to absorb the water so if you wait until you are thirsty during exercise you will lose some performance at least until the water is absorbed, therefore it is better to try and anticipate the thirst and maintain performance levels.

Also with hunger if you can anticipate it and eat shortly before you become hungry then you will eat less than if you wait until you are hungry and then make some dinner.

As has been said by someone else too Panorama is not my first choice of reliable reporting.
galpinos - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to galpinos)
> [...]
>
> because the body can only respond to its hydration level at that moment - it can't anticipate the fluid you will be losing in the next 30min - therefore, it makes sense to be drinking before you get thirsty during exercise.

The thrust of the article is that the body can cope with losing that fluid in the next thirty minutes, will tell you when it requires more and you trying to second guess the body will have no performance benefit. The ability of the body to regulate water and salts is pretty impressive and drinking an extra sports drink when YOU, not your body, think you need it will just lead to expensive wee.
galpinos - on 08 Aug 2012
In reply to ajsteele:
> (In reply to galpinos)
>
> Simply because it takes a while for your body to absorb the water so if you wait until you are thirsty during exercise you will lose some performance at least until the water is absorbed, therefore it is better to try and anticipate the thirst and maintain performance levels.

I believe the point of Tim Noakes' argument is that there won't be a dip in performance. The body knows what it's doing. he goes on to say that there is very little eveidence out there and what there is, is from the sports drinks companies themselves. He's done a fair bit of research and is an ultra runner (I believe, he might be rubbish though).
Tobias at Home - on 08 Aug 2012
In reply to DancingOnRock: that's not really relevant to what i'm saying - i'm going to lose water, i might as well drink now and start replacing it rather than waiting till i've lost 1l and then try to run with a litre of fluid sloshing around in my stomach before it has been absorbed.

i'm not sitting here suggesting everything the sportsdrinks companies say is gospel. i'm just saying if i'm going to lose a litre of water anyway why wouldn't i start replacing it immediately rather than waiting to reach a threshold level of dehydration when my body says it could do with topping up.
Tobias at Home - on 08 Aug 2012
In reply to galpinos: as an aside, i was pacing a certain poster on this forum on a 100miler when she had to abandon due to the race doctor pointed out she'd have kidney failure if she continued as she was too dehydrated - she hadn't felt thirsty all race....
ThunderCat - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to ThunderCat)
> [...]
>
> :-) i didn't feel patronised - i think we are talking two different points - i'm all for listening to the body for what it needs - i just think when exercising i know better about what i'll need over the next 30mins than my body's hunger and thirst sensations.

Well I read it again and I think I'd have been patronised if I'd read it from someone else...I think you're just being a bit too gracious. :)

I think my main point is that for your average Joe Bloggs, you're in the gym and doing your stuff, you're going to have a drink when you get thirsty. You're never more than a few feet from your water bottle and you're not going to wait until you're dying of thirst.

Having the 100% optimum hydration level is going to be a deal breaker for a top level olympian, but otherwise, the worst than can happen is that you feel a little bit knackered a little bit more quickly. It's not going to have any great overall net effect on people like me or the 99% of the population that the advetising is actually aimed at.

I worry that the danger is people read and believe the advertising pumped out by water / sports drink manufacturers, believe it, and shell out loads on fancy drinks.

Absolute worse case scenario, they drink too much and damage themselves. More irritating case scenario, people spend too much money on crap and make a drinks corporation richer.

I think that's my main beef....when people perpetuate a myth about 'advanced hydration' (or anything else) without discussing it or even considering the fact that it may have been started by someone with a vested interest....

EG my favourite example of this kind of crap is the "SCIENTIFIC FACT!! TEA IS HEALTHIER THAN WATER!!!"*


http://news.bbc.co.uk/1/hi/5281046.stm


(*) funded by the British Tea Council.
Porridge the climber - on 08 Aug 2012
In reply to galpinos:
> (In reply to Tobias at Home)
> [...]
>
> The thrust of the article is that the body can cope with losing that fluid in the next thirty minutes, will tell you when it requires more and you trying to second guess the body will have no performance benefit. The ability of the body to regulate water and salts is pretty impressive and drinking an extra sports drink when YOU, not your body, think you need it will just lead to expensive wee.

Exactly. If you think of it in evolutionary terms, it would be a short-lived gene that didn't tell ancient man, tracking his quarry across the baking savannah, that he would need some water BEFORE his performance started to fall.
Tobias at Home - on 08 Aug 2012
In reply to galpinos: personally, i think he has a point that a lot of what the drinks companies say isn't backed by evidence...i think the idea you can't anticipate food/drink needs in advance is going too far the other way....
ads.ukclimbing.com
ajsteele - on 08 Aug 2012
In reply to galpinos:

I've ran a fair bit myself and I know from my own experience that as soon as I stop anticipating it myself my performance drops significantly. It has happened to me twice during marathons where for whaetever reason I have kind of forgot to stay on top of my hydration and by the time I realised I was thirsty my performance was already dropping.

Another thing that happens to quite a lot of runners when dehydrated is they get stomach cramps and "runners trots" which is unpleasant to say the least.

All I have is anecdotal evidence based on my own experience but for me it definitely helps to stay hydrated. However I only drink water, no sports drinks as I don't really believe the whole electrolyte thing plus in the past when I have tried sports drinks they have disagreed with my stomach.
Tobias at Home - on 08 Aug 2012
In reply to Porridge the climber:
> (In reply to galpinos)
> [...]
>
> Exactly. If you think of it in evolutionary terms, it would be a short-lived gene that didn't tell ancient man, tracking his quarry across the baking savannah, that he would need some water BEFORE his performance started to fall.

not necessarily. for starters, i'm pretty sure we aren't designed to run for 10s of miles so this sort of high intensity endurance work doesn't really have much of an evolutionary background.

secondly, there's benefits whilst you're running/fighting to not worry about your hydration state. wait till you've clubbed the dinosaur and then have a celebratory pint.
galpinos - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to galpinos) personally, i think he has a point that a lot of what the drinks companies say isn't backed by evidence...i think the idea you can't anticipate food/drink needs in advance is going too far the other way....

I'm not syaing he's right (though I'm more inclined to believe him than sports drink companies' research) but I do think the "whole drinking lots of water is good for you/can't go anywhere without an evian bottle" thing has got out of hand.
Porridge the climber - on 08 Aug 2012
In reply to Tobias at Home: Ha ha. Did make me chuckle.

I thought that was what our physiology was particularly suited to though? I might just be making that up mind.
Andy
galpinos - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to galpinos) as an aside, i was pacing a certain poster on this forum on a 100miler when she had to abandon due to the race doctor pointed out she'd have kidney failure if she continued as she was too dehydrated - she hadn't felt thirsty all race....

Maybe the system isn't foolproof! (Not saying said poster is a fool....) From my own experience, I know I've ignored signals from my body like thirst and hunger when pushing myself and paid the price. I think the signs were there, I just ingonred them. (again, I'm not saying that's what happened in the above quoted case)
Tobias at Home - on 08 Aug 2012
In reply to Porridge the climber: why would we run 10s of miles? what animal would we be chasing like that? for any other travel, walking makes lots more sense.
galpinos - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to Porridge the climber)
> [...]
>
> not necessarily. for starters, i'm pretty sure we aren't designed to run for 10s of miles so this sort of high intensity endurance work doesn't really have much of an evolutionary background.

Totally off topic but I believed the current thinking was that we were designed to run for long distances, we used to hunt stuff and track it for ages at a relatively slowish pace until it was tired and easy to take on (not fast sprinting type hunting like big cats etc)
>
> secondly, there's benefits whilst you're running/fighting to not worry about your hydration state. wait till you've clubbed the dinosaur and then have a celebratory pint.

When adrenaline kicks in, al lot of the body's signals get masked in my experience!

galpinos - on 08 Aug 2012
In reply to Tobias at Home:

From the font of all knowledge:

http://en.wikipedia.org/wiki/Persistence_hunting

Right, coffee break is over, back to work!
Tobias at Home - on 08 Aug 2012
In reply to galpinos: hah! every day's a skool day!
Tobias at Home - on 08 Aug 2012
In reply to galpinos: "Depending on the specific conditions, hunters of the central Kalahari will chase a kudu for about two to five hours over 25 to 35 km (16 to 22 mi) in temperatures of about 40 to 42 °C (104 to 108 °F)."

we need to ask them what their hydration strategy is! :-)
ThunderCat - on 08 Aug 2012
In reply to galpinos:

Well whatever. All I know is that:

I've got the afternoon off work because the I've got a plasterer in sorting out the hallway,

I've had a couple of cheeky mid-week beers already,

My body is telling me that I need some more, ahem...hydration...
Gordonbp - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to galpinos)
> [...]
>
> because the body can only respond to its hydration level at that moment - it can't anticipate the fluid you will be losing in the next 30min - therefore, it makes sense to be drinking before you get thirsty during exercise.

Sorry that's just nonsense. I've been in plenty of situations where I've been doing hard physical exercise and when it has either been physically impossible to drink or water has to be conserved because we didn't know when we might get a re-supply.
I never suffered anything more than just feeling thirsty because I didn't drink before hand.
DancingOnRock - on 08 Aug 2012
In reply to ThunderCat:
> (In reply to Tobias at Home)
> [...]
>
> Eat when you are hungry, and only when you're hungry. Stop when you cease being hungry.

LOL

Stop well before you cease being hungry, wait 20minutes, eat more if necessary.
alicia - on 08 Aug 2012
In reply to galpinos:
> (In reply to Tobias at Home)
> [...]
>
> Maybe the system isn't foolproof! (Not saying said poster is a fool....) From my own experience, I know I've ignored signals from my body like thirst and hunger when pushing myself and paid the price. I think the signs were there, I just ingonred them. (again, I'm not saying that's what happened in the above quoted case)

Don't be so sure the poster isn't a fool:) I think the biggest problem with the "drink to thirst" idea is that it doesn't account for the nausea that many (most?) runners get in ultras. I was the person Toby was talking about and I definitely was not thirsty at the time. I certainly wasn't going fast enough to be ignoring thirst!

Also, in Noakes' own work, he talks about how studies have shown that ingesting carbohydrates during marathons/ultras does have proven benefits. But I'm never hungry during marathons or ultras, so obviously hunger isn't a good mechanism to judge carbohydrate intake by. Why should thirst be any different?
DancingOnRock - on 08 Aug 2012
In reply to Nath93: I think one thing to be mindful of is that 'experts' say that 1% dehydration can lead to a 30% drop in performance. What does 1% dehydration equate to? If a 75kg person has 40litres of water in their body, are they 1% dehydrated if they lose 400ml of water? If I go to the loo I'm then dehydrated?

There's far too much mumbo jumbo and generalisations punted around. Part of running (and any sport) is learning how your body responds to what you put it through. I know through years of experience, how much water I need to take on board or will use on any particular day for any particular activity. This is a combination of looking at the weather. using thirst, listening to advice, forgetting to take water with me, having my bottle roll off the side of a mountain and of drinking 500ml and trying to run while it sloshes around inside me.

Man has evolved over millions of years to his advanced state because he learns and is able to predict what will happen in the next 30mins/Day.

I fear for our evolution because instead of learning by experimentation, we seem to only learn through marketing, blindly following 'experts' or relying on Google.
DancingOnRock - on 08 Aug 2012
In reply to alicia:
> (In reply to galpinos)
> [...]
>
> Don't be so sure the poster isn't a fool:) I think the biggest problem with the "drink to thirst" idea is that it doesn't account for the nausea that many (most?) runners get in ultras. I was the person Toby was talking about and I definitely was not thirsty at the time. I certainly wasn't going fast enough to be ignoring thirst!
>
> Also, in Noakes' own work, he talks about how studies have shown that ingesting carbohydrates during marathons/ultras does have proven benefits. But I'm never hungry during marathons or ultras, so obviously hunger isn't a good mechanism to judge carbohydrate intake by. Why should thirst be any different?

But you've learned through your experience. I learned through experience of having one of my friends collapse at the end of a 50miler because although we'd tried to feed him all day, he'd not been hungry. In fact none of us had been hungry or thirsty because we were too busy reading maps and pacing, our support crew had been forcing us to eat.

Ultras are different to any other sport and it's experience rather than instinct that will get you through.
alicia - on 08 Aug 2012
In reply to DancingOnRock:
> (In reply to Nath93) I think one thing to be mindful of is that 'experts' say that 1% dehydration can lead to a 30% drop in performance. What does 1% dehydration equate to? If a 75kg person has 40litres of water in their body, are they 1% dehydrated if they lose 400ml of water? If I go to the loo I'm then dehydrated?
>
Yeah, I think that's the better part of Noakes' book--pointing out that it's not necessarily bad to be somewhat dehydrated. I just wish he went into a little more detail on how much is known about what the boundaries of "okay" are; he talks about studies in which 4% to 7% body weight loss was fine, but also mentions a woman with 11% body weight loss who also had kidney failure (though he claims later in the book that there's no evidence that dehydration causes kidney failure, which my doctor friends have disagreed with...), without a whole lot of discussion.
DancingOnRock - on 08 Aug 2012
In reply to alicia:
> (In reply to DancingOnRock)
> [...]
> Yeah, I think that's the better part of Noakes' book--pointing out that it's not necessarily bad to be somewhat dehydrated. I just wish he went into a little more detail on how much is known about what the boundaries of "okay" are; he talks about studies in which 4% to 7% body weight loss was fine, but also mentions a woman with 11% body weight loss who also had kidney failure (though he claims later in the book that there's no evidence that dehydration causes kidney failure, which my doctor friends have disagreed with...), without a whole lot of discussion.

He also suggests that weight loss isn't a particularly good indicator of water loss. Just because you're burning fuel doesn't mean you are losing water. In any case I'm yet to see a set of scales that are accurate and repeatable to 1kg outside of a lab.
alicia - on 08 Aug 2012
In reply to DancingOnRock:

That might be true, but the studies he's citing approvingly all used weight loss as representative of water loss. I think the idea is that the amount of weight loss from fuel loss is going to be minimal in comparison to water loss.

The scales are an issue as far as regular races go, but hopefully the studies Noakes is talking about used lab-quality scales!
John1923 - on 08 Aug 2012
In reply to Tobias at Home:
> (In reply to ThunderCat)
> but that's my point - if your doing exercise, you are using water at a particular rate. there is a lag in how long it takes for your body to absorb new water

The lag is about 15 min, for complete distribution of 1 litre of water.

When you burn stored glycogen water is produced as a waste product.

You only need to drink if it is hot and you are sweating. Even then you don't need to drink much. In fact, thirst is a good guide.
DancingOnRock - on 08 Aug 2012
In reply to John1923:
> (In reply to Tobias at Home)
> [...]
>
> The lag is about 15 min, for complete distribution of 1 litre of water.
>
> When you burn stored glycogen water is produced as a waste product.
>
> You only need to drink if it is hot and you are sweating. Even then you don't need to drink much. In fact, thirst is a good guide.

This may have been what he was alluding to when he said that you don;t lose water as you burn fuel. So I've probably got it confused there.
Tobias at Home - on 08 Aug 2012
In reply to John1923: Think we might have different ideas of what constitutes exercise if you are including activities which don't generate sweat!
Tobias at Home - on 08 Aug 2012
In reply to John1923:
> (In reply to Tobias at Home)
> [...]
> When you burn stored glycogen water is produced as a waste product.
>

And during how much of an endurance event are you being fuelled by stored glycogen normally?

Tobias at Home - on 08 Aug 2012
In reply to Gordonbp:
> (In reply to Tobias at Home)
> [...]
>
> Sorry that's just nonsense. I've been in plenty of situations where I've been doing hard physical exercise and when it has either been physically impossible to drink or water has to be conserved because we didn't know when we might get a re-supply.
> I never suffered anything more than just feeling thirsty because I didn't drink before hand.

Yeah water is totally overrated. Dehydration is just something made up by the drinks companies...
DancingOnRock - on 08 Aug 2012
In reply to Tobias at Home: I think the point is that drinks companies and flawed studies are the ones suggesting that over-hydration is the best option.
crispycodd - on 14 Aug 2012
In reply to Tobias at Home:
And during how much of an endurance event are you being fuelled by stored glycogen normally?


Fat will be a primary fuel, rather than glycogen, during prolonged exercise but utilisiation of fat for energy also produces water.

An interesting aside is that whales that fuel themselves primarily with fat never drink! (Salt water is not good for mammals to drink.) But then again they don't sweat either.
alicia - on 14 Aug 2012
Nath93 - on 14 Aug 2012
In reply to Nath93: Whoa, forgot I even posted this up ! Some interesting responses, plenty food for thought !

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