I would be surprised if it amounted to that much though really. I'm sure the bulk percentage of weight loss during exercise will be in fluid. InterestingQuote:
Originally Posted by Mike T
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I would be surprised if it amounted to that much though really. I'm sure the bulk percentage of weight loss during exercise will be in fluid. InterestingQuote:
Originally Posted by Mike T
Quite frankly I'm struggling to understand Mike T's point. If I'm thirsty I have a drink and if I think I'm going to be thirsty I take a drink with me. I couldn't give two hoots about glycogen and CO2 :).
...but carrying water may, under some circumstances - race not too long, weather not hot - result in an inferior performance - that's the point ....Quote:
Originally Posted by Stolly
Hi Mike
Interesting stuff. You have helped me work out my hydration strategy for the Edale Skyline.
One thing I have noticed though is no matter how much beer I drink the night before, I always wake up thirsty.:wink:
I think Mike's point is valid. When marathon training I'd do 20 mile runs without water and had no problems at all. My thinking was that if I was physiologically trained to run that far dry, then on race day going further and faster and with water available, I'd get a good result. This worked for me under say 70 F. Hotter weather definitely needs more water intake.
Of course, water is readily available every 3 miles on a marathon if you need it. It's usually available on the fells too, though not necessarily in the right place. I usually carry a small amount on the hills as a reserve, and drink and top up wherever possible. It's a different sort of running, hard climbing can increase your body temperature, wearing too much clothing and carrying a few pounds in weight can do the same. So there are more variables compared to a simple road race.
People differ from each other, but I think that if you're 'sweating like a pig' and leaving salt crust on your face, there's a possibility, at least, that your body is carrying too much of both and is trying to get rid of it.
Yeah but I wouldn't carry water on a short race would I? I could equally claim that not drinking water on long races will cock up your performance - the carnage of cramp at the top of Whernside in the 3P being a good example. (And yes before you go all scientific on me I appreciate that cramp isn't necessarily just caused by dehydration).Quote:
Originally Posted by Mike T
Just as there are too many variables for what is right for me being right for you (weight, fitness, speed, terrain, distance, weather, ascent, availabilty of streams on route, propensity to sweat and what you're wearing all playing their part), the same goes the other way round. And quoting experiences in marathons doesn't equate to the hills anyway - there are less and sometimes no water stops in fell races, they take longer per mile, always include steep climbs usually right from the off and runners often need to carry more safety equipment and clothing, which all adds to them being able to get hotter quicker. I haven't ever run a road marathon and the only longish road races I have ever run are the Coniston 14 and the Langdale half and in both those road races, despite them being quite hilly, I've not needed much water.... and not needed to carry any in any event because of water stations. That though means diddly squat when up in the hills, especially solo running.
.....and when they find out that using 1 kg of fat results in the production of over 1 litre of water ....
This may be of interest/help:
http://sportsmedicine.about.com/od/h...rHydration.htm
Do note the sponsored links. See the following from the Medical advice section of The West Highland Way race:Quote:
Originally Posted by Stef F
3) I further recommend, on the basis of the literature evidence, and my interpretation of it, application of nature’s guide to fluid replacement, thirst. We should not be surprised that nature allows some degree of fluid loss while exerting ourselves, before developing thirst. My impression is that, when drinking by thirst, 2-4% weight loss is normal, non-detrimental and hugely (but not totally) reduces the likelihood of EAH. I note the articles which describe these findings accept this state of affairs, identify its advantages, but hold back from recommending 2-4% weight loss directly, although do so indirectly by implying we do not aspire to weight maintenance.
4) Finally, sources of guidance on fluid replacement are provided by the various authoritative bodies, including the International Marathon Medical Directors Association (IMMDA, 2006) which advocates a fluid intake during marathon running of 400-800mls/hr, and the American College of Sports Medicine, 600-1,200mls/hr. Based on the lesser intensity, through greater distance, of the WHW race, you should expect a fluid intake at or below the lower limits of these recommendations. You will note these recommendations, in keeping with much of the literature I have read, demonstrate a difference in opinion on fluid intake between South Africa and the United States, with the Americans generally advocating greater intakes, often advocating weight maintenance and drinking in excess of thirst, if necessary, to achieve that. In drawing your own conclusions, it may help to know the fluid consumptions of the two most seriously ill athletes with EAH from the 2005 race were 500 and 600mls/hr, with sodiums 127 and 120mMol/l respectively (<130 = EAH). The limited evidence from the WHW race to date does not, in my opinion, support the American recommendations.
EAH is exercise associated hyponatremia - water overload - nasty, can even be fatal, sometimes with very little warning.
I expected to lose weight in a marathon, about 3 or 4lbs, principally water. I always found afterwards that 7 or 8 pints of Guinness filled this lacuna to my satisfaction.
I believe it's the case that, whilst no-one has died of dehydration in a marathon, several have died of hyponatraemia.