Dehydration tips

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  • #23377
    ianrobo

    On warm rides I suffer heavily from sweating and thus dehydration issues. For example when riding in France for 75 miles I could not eat anything at night as mouth too dry etc.

    I drink loads, carry 2 750ml bottles, use rehydration tablets, gels everything but still nothing helps.

    Anyone got any tips to stop this apart from drink even more etc.

Viewing 15 replies - 1 through 15 (of 28 total)
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  • #834129
    0
    Welsh boy

    Thanks PaulJ, i think that
    Thanks PaulJ, i think that needs a coffee for me to get my head around but it is quite surprising!

    #834127
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    jstone1

    Well worth a read (though
    Well worth a read (though heavy going at times) – thought provoking and has changed how I think and approach hydration : http://www.humankinetics.com/products/all-products/waterlogged

    Bottom line – plain water, drink when you want, and be very wary of those funded by or selling you water with colouring, sugar & salt.

    More here (e.g. dehydration *not* reducing performance – in fact, event winners seem to be most dehydrated) :
    https://www.bcsm.org/a-review-of-waterlogged-author-tim-noakes/
    http://m.runnersworld.com/drinks-hydration/thirst-v-dehydration-the-continuing-saga
    http://www.ncbi.nlm.nih.gov/pubmed/24055782

    It’s all fascinating stuff, especially the serious and potentially lethal issues with overhydration.

    #834125
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    DavidC

    Further to abudhabiChris’s
    Further to abudhabiChris’s hot-climate advice: I am in Al Ain (and I occasionally cross paths with Chris), about 90 minutes inland from Dubai. In the summer here the temperature is generally a bit higher than in Dubai but we have almost no humidity — very hot and very dry conditions.

    We also do 3+ hour rides in the summer. Personally, I mostly drink plain water and eat solids about half-way through a ride, when we stop at a shop (‘normal’ snacks, not ‘sports’ snacks). When it is very hot I’ll take one or two small chocolate milk or juice boxes (never citrus for me), and drink them in the first 30-45 minutes, before getting into the water bottles.

    In the summer we easily go through 3-4 liters of fluids for a 3 hour ride, but in the cool season I often don’t even finish two bottles for the same distance.

    #834123
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    ianrobo

    Well went well today but
    Well went well today but obviously no heat !!

    Used abudhabiChris’s advice and pee OK when I came home !

    #834121
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    Paul J

    Welsh boy: Yes, I am. I did
    Welsh boy: Yes, I am. I did the numbers originally to prove that CO₂ weight loss would be negligible and hence most weight loss would be through water. I was surprised to find the opposite – exhalation of CO₂ can lead to a lot of weight loss. Easily hundreds of grammes, up to even a kilogramme for someone with a high VO₂Max doing 3 or 4 hours of high intensity cycling.

    VO₂Max in fit cyclists ranges from around 45 ml/min/kg to 75 (elite).

    There is 1:1 O₂:CO₂ exchange when burning sugars, and 1:0.7 for lipids. (See respiratory quotient).

    So at the lower end, a 70 kg rider with a 45 ml/min/kg, exercising for 3 hours at 60% of VO₂Max, at around 0.8 average carb/lipid, would exhale 45*70*0.6*0.8*60*3/1000 = 272 litres of CO₂. To get a rough estimate of weight, lets use the 1.977 gramme/litre density of CO₂ at 1 stm and 0° from wiki (not quite right for body temperature, but hey, this will overestimate a little). 272 * 1.977 = 543 grammes.

    A 70 kg rider with a 70 ml/min/kg VO₂Max, for 3 hours at 75%, at 0.9 average O₂:CO₂ (i.e. mostly sugar burning) would be 595 litres of CO₂ exhaled = 1.188 kilogrammes.

    So the CO₂ you exhale can add up to a noticeable weight. This is sort of surprising initially. However maybe not so much when you think about it. You’re burning up huge amount of energy when you cycle long distances. That energy comes from turning sugars and fat mostly into water and CO₂ (the definition of burning). Water molecules (H₂O) weigh less than CO₂ molecules – carbon is obviously much heavier than hydrogen, after all, and 2 oxygen molecules are double the weight of one 😉 . So looked at this way, it perhaps isn’t surprising after all.

    Exercise produces energy by turning food into some water and even more (by weight) CO₂ – which you breathe out.

    Edit: Managed to forget to multiply by the weight, however this was almost cancelled out by an extra multiply of 60, as if I was dealing with ml/s/kg. Fixed the calc & numbers above.

    #834119
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    Colin Peyresourde

    There is a bit of over think
    There is a bit of over think in hydration. There’s a story on cycling weekly about a nutritionist who suffered hyponutremia when she drank 3.5 litres during a marathon in order to ensure she continued to be hydrated….the article basically goes on to explain that a little dehydration is fine.

    But if you are doing 3+ you need to make sure you’re drinking fairly constantly throughout. Depending on how hard you have worked and the conditions post ride drink as many bidons of water as you need until you pee. Don’t gulp the water down, but just consistently sip. Pee and continue to drink until you pee again. Post-ride (we’re talking 3+ hours still ) your body is undertaking loads of metabolic activity. Reallocating resources and this uses a lot of water and a lot of carbs. 4:1 is a good drink to have, but the point is that you need to keep your vascular system topped up and flushing through the waste products from the ride. The more you flush this metabolites through the better you will sleep and feel better next day.

    Don’t gulp fluids down as you will not process them properly. There’s a limit to effective fluid absorption so throwing it down like you were competing with the university rugby team won’t help (and you’ll suffer hyponutremia or cramping). Sip and sip constantly. You don’t want to feel bloated.

    Some problems come from taking excessive electrolytes like stomach cramping so they are not all they are cracked up to be. We cyclists/athletes are easily sold to, not to say they don’t have their place. Use gels sparingly – they are a get out of jail free product. But they can cause more problems than they solve – diarrhoea and sugar crashes are not ideal. People use them as a crutch to prevent bonking, but much better analysis of your work rate and eating will mean that you don’t come near using these. I put one in my pocket, but it’s like the fire hydrant at work – I hope I never have to use it).

    #834117
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    ianrobo

    thanks Chuck may watch that
    thanks Chuck may watch that tonight with crap on TV !

    #834115
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    sergius

    Everyone is different, I tend
    Everyone is different, I tend to make do with the two 750ml bottles I take out with me, whether it’s for 2 hours or 5. There’s been a few times where I’ve run out at the end of a really long ride – but I generally just try and pace my liquid intake to how far I have to go.

    Food wise, I tend to stick to Malt Loaf. Nothing for rides under 2 hours, for longer rides a couple of pieces of Malt Loaf every 1.5 hours or so.

    I do make sure I have a decent porridge breakfast before every ride though.

    #834113
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    ChuckB

    This is the best I have seen,
    This is the best I have seen, and not from any drinks company

    #834111
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    ianrobo

    Quince wrote:It.
    Urine colour

    Quince wrote:
    It.

    Urine colour is generally taken to be a half-decent ‘litmus-test’ for dehydration. The deeper the colour, the less hydrated you’re supposed to be. So if your urine is often deep yellow, you could think about sipping more water off the bike.

    I know that but last time in bad heat I did not pee for 6 hours after a ride until I drunk loads 🙂

    #834109
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    ianrobo

    CXR94Di2 wrote:I drink 750 ml

    CXR94Di2 wrote:
    I drink 750 ml per hour of electrolyte drink. Eat nothing for 1-1.5 hr rides. 2hr rides same fluid and 1 banana. 3 -4 hr rides I take same fluid and eat 35 g of carbs per hour whether flapjacks or bananas.

    This is so interesting because everyone says have someone to eat every 20-30 mins even if not hungry …

    yet I agree on a 2-3 hour ride rarely actually feel I need it but energy is different from dehydration not bonked for years now

    #834107
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    Quince

    I think Chris and Crikey have
    I think Chris and Crikey have made some very good points. Another thing probably worth bearing in mind (although I’m no expert), is that hydration isn’t confined to the time on the bike, as isn’t an immediate process. If you go out leave the house already dehydrated, you’re fighting an uphill battle from the start.

    Urine colour is generally taken to be a half-decent ‘litmus-test’ for dehydration. The deeper the colour, the less hydrated you’re supposed to be. So if your urine is often deep yellow, you could think about sipping more water off the bike.

    But it’s probably not worth getting too freaked out about. As the page above has stated, our bodies get certainly get by without a constant supply of Sugarade and Electrogels, otherwise hunting would have been a bit awkward. The fact that many companies stand a lot to gain by fostering a dependence on such products goes some way to explain how people come to think only in terms of them.

    Not that there’s anything necessarily evil or faulty about them, but they’re not really necessary for every single ride. It might be worth seeing what you can comfortably do on just water alone

    #834105
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    Welsh boy

    Paul J wrote:Note that not

    Paul J wrote:
    Note that not all the weight loss is from water… it’s also from burning sugars and fats and breathing out CO₂.

    Are you really saying that breathing out CO2 contributes to weight loss?

    #834103
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    CXR94Di2

    I drink 750 ml per hour of
    I drink 750 ml per hour of electrolyte drink. Eat nothing for 1-1.5 hr rides. 2hr rides same fluid and 1 banana. 3 -4 hr rides I take same fluid and eat 35 g of carbs per hour whether flapjacks or bananas.

    #834101
    0
    ianrobo

    I have done that with shorter
    I have done that with shorter rides to save cash. Will try your method tomorrow but doubt dehydration will be an issue !!

Viewing 15 replies - 1 through 15 (of 28 total)
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