bikerjp

I did a 200km ride a couple months back and pretty sure I didn't drink enough (dark urine, felt like crap near the end). I decided to try and figure out my hourly usage and yesterday weighted myself before and after a 2 hour ride. I lost 3lbs in addition to drinking about 30oz on the ride. Given that it's approximately 16oz of water per pound that's 48oz lost plus 30oz consumed for a total of 78oz of water in 2 hours. Given that is was cool and I wasn't riding overly hard I'm assuming this is probably the low end of the spectrum and on hot days would need even more.

So, this works out to about 40oz/hour on the low side. Not sure what the high side would be. I normally carry two 26oz bottles so this seems to work out to about 1.5 - 2 bottles per hour. That seems like a lot. I normally do rides of 3 hours or less and usually just take 2 bottles in addition to a bit of pre-hydration before the ride. I suspect a 3 hour ride isn't enough to notice dehydration and I don't know how I'd get 4-6 bottles worth when there are not many options for water on my routes. On a longer ride it's clearly more crucial to get the right amount.

So, my question is does approximately 1-5-2 bottles an hour seem excessive? On longer rides I do eat and drink electrolyte mixes, juice or something in addition to water so mainly just asking about total fluid needs over an 8-10 hour ride. Thanks.

redlude97

1-2% water loss is acceptable for endurance activities so for most people 3-4 lbs loss by the end of a long ride is ok. So plan around that. 1-1.5 bottles on a summer century is pretty normal. You can always carry and extra bottle in your jersey

DXchulo

Even on hot days I have trouble drinking more than 1 bottle an hour. I've tried, but it just makes my stomach hurt. I've tried lots of formulas but have never noticed any difference in performance

These days I just drink to thirst, which is a lot less than most people recommend. On a normal day I'll do around one bottle every 2 hours. If it's hot and there's a climb I will hit the 1/hr mark.

hamster

Were you drinking water or a sports drink, and did you pee at all between weightings? That could have obscured the results. 40 oz/hour does sound like too much. I drink 24 oz/hour even in hot weather and it's normally enough.

I did a 200k yesterday (300k cut short by a mechanical). 8300' of climbing, 10 hours with temps around 90 during the second half.

* 4 full bottles ~(90 oz total) at the start
* Bought 3 quarts (96 oz) of Gatorade at 5 hour mark
* Stopped to refill bottles again at 8:30

datlas 

Everyone is different and even for an individual it will depend on temperature and humidity. Maybe you need more than average.

Average is one bottle/hour, but I know some people who go through 2 bottles/hour and some who go 2 hours on one bottle.

OldsCOOL

I drink 48oz in a 4hr ride in 85-90deg weather with 16mph pace.

Velo Vol 

It depends on the temperature. A 75F ride is a lot different than a 85F ride.

1986raleigh

Yesterday's ride was 37.5 miles, took 2.5 hours, cool, 80 degrees, humidity about 75%

I drank a 16.9 oz g2gatorade just before I left and took three more along plus two 24 oz polar water bottles of water. I knew how far I was riding and paced my consumption to match, I was completely dry when I finished. 115.6 oz or 7.2 lbs intake and I still lost about four lbs body weight.

Time to break out the camelback again.

I'm slow, sweat like a horse, drink like a fish and prone to dehydration if I don't drink fluids almost constantly and consistently.

My last supported ride, the goatneck I was drinking four polar bottles between every rest stop which was every 8-10 miles

Short answer.. it depends, what barely keeps me from heat exhaustion and dehydration may well cause you to slosh like a half empty water jug.

gc3

Water? Who needs fluids? HTFU...

1986raleigh

Yea let's hear you say that when every muscle in your body is knotted from dehydration and all you can do is lay on the floor and suffer.
Been there, done that, got the t-shirt.

Bacciagalupe

Drink when you're thirsty.

Really.

How much water should you drink during a marathon? | Life and style | theguardian.com
Almost Everything You Know About Hydrating is Wrong | adventure journal

Cycling might be slightly different, but the current recommendations are all the nice, simple, easy "drink when you're thirsty."

mike12

I never see anyone mention body weight on these type threads. Isn't that a pretty important factor? At 135lbs I assume I need a lot less water intake than a 200 pounder.

MikeWMass

I agree, the current recommendations are to drink when you are thirsty. Obviously, if you are dragged out and getting cramps, you need to become more attuned to your inner thirst.
Having said that, if you consider 80 degrees and 75% humidity cool, then you will probably need to drink a lot more than most people here are talking about.
Every summer we go to New Hampshire and I ride around Lake Winnepasaukee. It is about 67 miles, counting getting from my cottage to the main road and then back. Usually I can do it with 2 bottles of water (24 oz bottles). Last year it was 90 degrees and humid, and I ended up buying four 16 oz bottles of water in addition to what I started with, and was still thirsty when I got back.

hamster

I would agree that we need to correct for height or fat-free weight. Most 200 pounders have much more fat than most 135 pounders. If I'm 5'6" and you're (say) 6'2" and I need 24 oz/hour in certain conditions, then you need 24*(74/66)^2=30 oz.

I'm not sure about adjusting for body fat too.

joshnc

Yes and some sweat more than others. I went out with 1 bottle today the start was 64 degrees and it was to much for a two hour ride. The short rides of 1 hr to 2hrs really doesnt matter if it is pleasant out. If it is 95 degrees that is another story.

achoo

The problem with that is when it's really hot, humid, and you're riding hard.

By the time you get thirsty you can be deeply dehydrated.

FWIW, I'll slug an entire bottle before starting a ride when it's hot out.

Gatorfreak

I usually drink one bottle per 25 miles when it's hot and a bit less when it's not. I've found that beyond 50 miles I need electrolytes and not just water or I'll feel terrible. If you're a big person then you'll probably need to drink more than a smaller person. I'm 137 lbs so my fluids intake is probably less than many here.

1986raleigh

I read the article and comments. I drink when I am thirsty, mostly water.

The question the OP asked concerned how much on a long ride. The best answer is it depends on conditions, conditioning, temps, humidity, amounts you have drank in the last twenty-four hours,urination rates, etc.

Heat stroke kills quickly, if you are exerting yourself through exercise or work effort and suddenly stop sweating you better take quick action.

One issue I had transitioning from runner to cyclist was evaporation rates. It took a while to figure out just because my Jersey was not sweatsoaked I was still losing fluid I was just not able to Gage how muchh.

After a couple bouts with cramps I figured it out, drink to stay hydrated depending on conditions.

1986raleigh

Yeah I'm thinking my water consumption would make you slosh like that water jug I was talking about..6'4" 205 lbs... everything's relative...you have advantage in headwind too....

JohnDThompson 

It depends. Depending on your build, and that of the 200 pounder, you might also have higher surface area to volume ratio, which would increase fluid loss through sweat.

1986raleigh

Amen, by time I have a little sweat going I'm behind the curve.

1986raleigh

80 degrees and 75% humidity is a nice spring day in N Texas, ya want to talk hot just wait to July and August.

doctor j

^^^This^^^

64 hilly miles yesterday with two other riders. I drank twice as much as they did, half of what I drank was water, and the other half was PowerAde. The younger of the two was faster than me and drank/ate very little. Same for the other who is older than me and similar in speed to me. We all finished. well.

BoSoxYacht

In the heat of Phoenix summer weather I usually drink about 100oz of water/Gatorade for a 3hr ride. During the winter months it's about 25oz of water and 20oz of coffee.

Nachoman

I drank one bottle of water yesterday on a 50 mile ride. I probably should have drank more.