How much water per hour?

[Davidc]

You'll feel thirsty long before you start to be dehydrated. Small sips and frequently works best.

How much depends on the weather, the topography of the ride, and more.

There's more rubbish and old-wives-tales written and passed on on this topic than there is solid fact and good advice, so beware.

 

[TonyEnjoyD]

I normally drink well in excess of 2-3 litres of water a day, usually 6-8 300ml glasses plus tea or coffee.
Out on a ride, 20-35 I take one 500ml bottle, sometimes I finish it.
More than 30-35' I take 750 or two 500ml.
I take a mouthful periodically as I ride r at a natural stop, usually pee once every 25 miles and gently rehydrate at the end ( unless we ht McD's for a latte toward the end that is -forward planning )

 

[Paulus]

Drink when you are thirsty.

You should really drink BEFORE you are thirsty to keep hydrated. Take a small drink before leaving home and sip away on the move. I drink a 500 ml bottle every 20 miles or so depending on the weather. The warmer the weather, the more water.

 

[jefmcg]

Out of interest, how much water do you drink while road biking?

The reason I ask is, I done 25 miles this evening (not bad considering Saturday I done my furthest yet, 40 miles), but consciously this evening I drank less (water that is, I don't drink n ride ), as I done a similar distance 2 weeks ago, drank 500 ml of water before I started, then 2 x 750 ml bottles (both with a zero tab in each), finish the lot before the end of the ride (ride time 1:45 mins) and had a terrible stitch and stomach pain near the end.

Leave the zero out: I used a few tabs that came free with my water bottles (or is it the other way around?) and had stomach distress every time. As I could not think of a good reason not to take a little sugar, I replaced it with Rocks Squash - one of the only brands that has no artificial sweeteners - or SIS powder. Tastes nicer and no distress. Of course, you don't need anything, but I find sweetened water more palatable, so use it. Even then I did a slow Dunwich Dynamo (~12 hours) without needing a comfort break!

 

[jefmcg]

Bad news is that unless you are properly hydrated in the first place, coke, beer, coffee, tea all contain diuretics which increase the renal output exacerbating the situation

This is not true, unless you aren't a caffeine user. My nanna would have died of thirst, as she only drank tea ... and sherry!

http://www.snopes.com/medical/myths/8glasses.asp

 

[nickyboy]

As soon as your body suffers 2% dehydration (ie you have 98% of the ideal quantity of water in your body) you start to suffer drop off in ability to exercise. Now you don't even feel thirsty at 2% dehydration so the idea to wait until you are thirsty, then drink some, is tosh if you want to cycle to the best of your abilities. Of course, if you aren't bothered about a drop off in your cycling then you can allow yourself to become a bit dehydrated by waiting until you feel thirsty
The best advice seems to be to monitor your urine production. If you are still producing the usual amount of light coloured stuff during and after the ride you're fine. Anything else you're not

 

[PK99]

Drink when you are thirsty.

I my experience this is 180degrees wrong.

Rule of thumb:
Drink before you are thirsty
Eat before you are hungry.

On a 20 mile ride i might well do neither - and sometimes suffer from post ride cramps

20-30 miler zero calorie tab per bottle, carry two, probably only drink one

Above 30 I have recently taken to using a Carbohydrate drink from the start and feel the benefit both during the ride and in terms of recovery - my times over a standard 40 mile route are better than with zero cals.

Try weighing yourself starkers before and after a ride to give a measure of water loss - it is sometimes remarkably large!

 

[ufkacbln]

This is not true, unless you aren't a caffeine user. My nanna would have died of thirst, as she only drank tea ... and sherry!

http://www.snopes.com/medical/myths/8glasses.asp

That article does not mention diuretic effects, Di I am afraid I don't see the relevance

 

[derrick]

If i am not thirsty i don't drink. i drink when i feel like drinking, have done plenty of long rides 50+ miles without a problem.

 

[Davidc]

That article does not mention diuretic effects, Di I am afraid I don't see the relevance

Most of the second half of the article is about them!

nickyboy and PK99 would do well to read Barbara Rolls before suggesting drinking before feeling thirst (She's probably world number one on the subject).

 

[ufkacbln]

Most of the second half of the article is about them!

nickyboy and PK99 would do well to read Barbara Rolls before suggesting drinking before feeling thirst (She's probably world number one on the subject).

Sorry- it does still not mention the diuretic effects of these drinks when dehydrated.

The statement stands, beer, coke, coffee and tea are diuretics, and if you are dehydrated will exacerbate the situation

 

[Davidc]

Sorry- it does still not mention the diuretic effects of these drinks when dehydrated.

The statement stands, beer, coke, coffee and tea are diuretics, and if you are dehydrated will exacerbate the situation

The article covers the diuretic effects, which will vary little, if at all, with mild dehydration.

There's peer reviewed research on the subject showing that none of the drinks you mention have any dehydrating effect [1]. If you are aware of peer reviewed research to support your proposition please give details.

[1] Journal of The American College of Nutrition, vol19, p591

 

[PK99]

Most of the second half of the article is about them!

nickyboy and PK99 would do well to read Barbara Rolls before suggesting drinking before feeling thirst (She's probably world number one on the subject).

can you point me at an appropriate article, i can't turn one up with google... I can see general nutrition articles and debunking of the 8 glasses a day but nothing concerning hydration during endurance exercise.

 

[Gravity Aided]

Eat before you are hungry, drink before you are thirsty, was the recommendation of Paul de Vivie, or Velocio, french writer, and father of Sportif Cycling,Touring, and Randonneuring, as well as inventor of the derailleur to some extent. Rode many miles at a great rate of speed well into his seventies. Also publisher of Le Cycliste. Sound advice from a master.

 

[nickyboy]

Most of the second half of the article is about them!

nickyboy and PK99 would do well to read Barbara Rolls before suggesting drinking before feeling thirst (She's probably world number one on the subject).

Ref please. I can't find anything terribly relevant by googling. Conversely, by searching "effect of dehydration on exercise performace" there are loads of scientific, peer reviewed articles. Here is a good one:

http://www.nature.com/ejcn/journal/v57/n2s/full/1601897a.html

They confirm you only need to lose about 2% of your normal water volume to see some drop off in performance.