Support road.cc

Like this site? Help us to make it better.

Dehydration tips

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.

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

Add new comment

28 comments

Avatar
Welsh boy | 9 years ago
0 likes

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

Avatar
jstone1 | 9 years ago
0 likes

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-cont...
http://www.ncbi.nlm.nih.gov/pubmed/24055782

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

Avatar
DavidC | 9 years ago
0 likes

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.

Avatar
ianrobo | 9 years ago
0 likes

Well went well today but obviously no heat !!

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

Avatar
Paul J | 9 years ago
0 likes

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  3 . 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.

Avatar
Colin Peyresourde | 9 years ago
0 likes

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).

Avatar
ianrobo | 9 years ago
0 likes

thanks Chuck may watch that tonight with crap on TV !

Avatar
sergius | 9 years ago
0 likes

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.

Avatar
ChuckB | 9 years ago
0 likes

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

http://youtu.be/eeIA261_gSw

Avatar
Quince | 9 years ago
0 likes

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

Avatar
ianrobo replied to Quince | 9 years ago
0 likes
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  1

Avatar
CXR94Di2 | 9 years ago
0 likes

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.

Avatar
ianrobo replied to CXR94Di2 | 9 years ago
0 likes
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

Avatar
ianrobo | 9 years ago
0 likes

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

Avatar
ianrobo | 9 years ago
0 likes

OK thats great mate so the £40 I spent last week on the stuff was a waste, dump it and go to the suggestion you made ?

You have given me something to think about for sure along with what Crikey said ...

So I presume from what you said diluted orange juice through a ride is good as they helps in effect keep you fresh ?

Avatar
ianrobo | 9 years ago
0 likes

OK thats great mate so the £40 I spent last week on the stuff was a waste, dump it and go to the suggestion you made ?

You have given me something to think about for sure along with what Crikey said ...

So I presume from what you said diluted orange juice through a ride is good as they helps in effect keep you fresh ?

Avatar
KirinChris replied to ianrobo | 9 years ago
0 likes

Not dump it, but just don't use so much of it. Look at it this way, your 40 quid will last a lot longer  4

Some people use orange juice, personally I like pineapple. About one third juice and the rest water.

Also on shorter rides, like an hour or so, try just using water, especially if it isn't a hard ride.

Avatar
KirinChris | 9 years ago
0 likes

+1 to what Crikey said, and the Science in Sport guys have a lot of good info and advice.

There is an entire industry devoted to getting you to drink more and put more powder, gels etc down your throat.

The electrolyte stuff just increases the concentration of salts in your body, because you replace the salts but not all the water. So you get thirstier.

The gels have nothing to do with hydration. Once you start consuming them you have to keep having them every 20 mins or you have a sugar crash. Don't use them until the last hour of a ride.

The dry mouth can probably be helped by having orange or something with lemon juice after the ride. It's just buildup in your mouth and the citric acid helps get rid of it. Track riders (no water allowed) sometimes have a lemon in their sleeve to suck through the jersey for this reason.

I would generally just use diluted juice for my hydration. On a long hard and hot ride (three hours) I might have a second bottle with a scoop of energy powder and half a tab of electrolyte - generally about half of the recommended amount.

And I would never have it as more than half my intake - in fact if I can get somewhere and refill with juice and water I will stay on that before going to the energy/electrolyte drink.

Also, if you feel the need for energy, eat solid food on the bike instead of powder and gels. Things like figs, apricots or dates, quartered apple slices and maybe something sweet like a biscuit with nutella or half a waffle (cut and folded) will give you better energy and taste nicer.

I'm riding in Dubai through the summer so I think I have a pretty good handle on it. As Crikey says, there's nothing wrong with a little dehydration, you just need to get used to it.

Avatar
Paul J | 9 years ago
0 likes

antigee: Note that not all the weight loss is from water. You also lose weight through aerobic metabolism and respiration. When your body burns sugars, the CO₂ is exhaled. Intense exercise over a few hours, this CO₂ can easily add up to several hundreds grammes to a kilogramme (depends on intensity/fitness and aerobic efficiency). The processes which create the CO₂ also create water, which replenishes some of what you sweat out.

In short, the weight you've lost isn't just from sweating water, it's also from burning sugars and fats and breathing out CO₂.

Avatar
Welsh boy replied to Paul J | 9 years ago
0 likes
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?

Avatar
Paul J | 9 years ago
0 likes

Avoid the gels perhaps? Those super-sugary gels can actually temporarily dehydrate your body by forcing water to have to move across the intestinal membranes from your bloodstream into the gut. Most of it will be re-absorbed, as your body digests the gel, but not necessarily all.

The other thing you can do is preload a little with water before leaving. Drink 500 mls before you go, if you can.

Avatar
ianrobo replied to Paul J | 9 years ago
0 likes
Paul J wrote:

Avoid the gels perhaps? Those super-sugary gels can actually temporarily dehydrate your body by forcing water to have to move across the intestinal membranes from your bloodstream into the gut. Most of it will be re-absorbed, as your body digests the gel, but not necessarily all.

The other thing you can do is preload a little with water before leaving. Drink 500 mls before you go, if you can.

I do try that and told to drink until you get to the point you need a pee and then you know you are topped up and exercise will do the rest.

I think the thing about Gels is that they are easy to digest and quite nice tasting. I have tried different bars etc on the road and just find if riding fast difficult to swallow.

On days like this obviously not a problem and the sip technique is perfectly adequate. Juts anything over about 24/25C does it

Avatar
antigee | 9 years ago
0 likes

having moved to Aus' a couple of years ago I tried to improve my knowledge on this topic - luckily Melbourne is relatively cool but summer days can be mid/high 30's usually on the days you've booked in an all day ride!

My only conclusion is that it is a combination of food and fluid because similar to a cold day you are moving your body outside of it standard operating conditions - so easily digested food is as important as drinking - pretty sure I read an article that gave some numbers on this but failed to find it - thought this was is but if you feel confused already  17

http://cyclingtips.com.au/2014/04/hydration-for-cyclists-how-important-i...

PS don't try the weigh before/after thing - did it after a longer than expected run on a 32deg day and it is very scary

Avatar
ianrobo replied to antigee | 9 years ago
0 likes
antigee wrote:

- pretty sure I read an article that gave some numbers on this but failed to find it - thought this was is but if you feel confused already  17

http://cyclingtips.com.au/2014/04/hydration-for-cyclists-how-important-i...

PS don't try the weigh before/after thing - did it after a longer than expected run on a 32deg day and it is very scary

Well that article seems to argue both ways !

Avatar
ianrobo | 9 years ago
0 likes

thanks Crikey now I am really confused !!

At the end of the day and it was very hot up to 34C I had drunk loads during race and after and yet cramping badly and could not eat as described.

What is that then ? What was I missing ?

Avatar
crikey | 9 years ago
0 likes

You're over thinking and over drinking.

You don't really need as much liquid as you think you do, and using electrolyte drinks and the like makes the problem worse, not better. Use water, and drink when you are thirsty, not to any other regime. Your body can cope perfectly well with a little dehydration, but you need to acclimatise to it by not constantly drinking all the time you ride.

Look at the Science of Sport website and search out the topics of dehydration, hydration and cramp. It will change the way you think...

http://sportsscientists.com/2013/01/dangerous-exercise-the-hype-of-dehyd...

Avatar
ianrobo | 9 years ago
0 likes

I know .... can not even use a camel back because I sweat so much the water/liquid heats up !

Avatar
kwi | 9 years ago
0 likes

Not a lot more than 'Drink more' can be said.
If you're dehydrating you're not taking enough on to replace what you're loosing through sweat and expiration.
Did read somewhere that go for an hours ride, weighing yourself before and after, and aim to drink about 75% of weight lost (1mil water =1 gram.) every hour during longer rides.

Latest Comments