How much water should a regular rider drink?
 

Hope this is the right sub-forum for such question.

They say a proper hydration is especially important for cyclists - as drop of liquids in their body will substantially increase probability of (permanent) knee injuries. But how much water is actually enough?

First of all, what I'm interested in is a solid, educated, well-grounded opinion. Ideally, approved by majority of athletes and sports doctors. As it seems like there are a lot of controversies around this subject. Some say it's enough to have 1 liter of water/isotonic per 30-50km, other sources claim you must drink 0.5-1 liter per 10km, or 1-1.5 liters per hour (in hot weather).

Those numbers vary greatly, and many of those who provide them only have their personal experience to back it up. So far, the most scientific approach to this I've seen is related to amount of water a human loses when exercising. Different sources claim it ranges from 0.5 liter to 1 liters (depends on the temperature) per hour.

Could somebody either confirm those numbers, or provide an alternative viewpoint? Let's structure it like this:

1. Recreational ride in a warm day (50 kms at 15 km/h, with a few breaks to have some rest, at temperature 18-25C)
2. High-performance ride in a warm day (50 kms at 20-30 km/h, no breaks, at temperature 18-25C)
3. Recreational ride in a very hot day (50 kms at 15 km/h, with a few breaks to have some rest, at temperature 35+C)
4. High-performance ride in a very hot day (50 kms at 20-30 km/h, no breaks, at temperature 35+C)

How much water per hour should one consume in each of those 4 cases?

Also, how much isotonic is more efficient than plain water? Is there some approximate coefficient, like "you will need 0.75 liters of isotonic instead of 1 liter of water"?

Enough so you are not thirsty.
Enough so that your mouth remains wet.
Enough your performance does not suffer.
Enough you are able to maintain proper body temperature regulation.
Not so much that you need to pee more than every hour or so.
Enough that your pee is nearly clear.

"Enough" varies with environmental conditions & level of exertion. There is no one set defined measured amount that applies beyond a specific individual in a specific set of circumstances.

How much wood could a woodchuck, chuck?

Enough so that you need to pee about every 3 hours. That's the gold standard. If you're not riding that long, don't worry about it. You can be about 1-1/2 quarts low before it begins to affect your performance. Color of pee is immaterial - depends on what you've eaten to a large extent. I ride with a guy who drinks about 12 oz. of water on a 60 mile ride. Another guy sweats so much one thinks it's raining when riding his wheel.

Isotonic makes no difference. Water's H2O and that's that. Electrolytes are a separate story. The need for them varies as much or more than the need for water. I drink plain water and take enough Endurolyte capsules that I stay a little thirsty. But that's a long ride tactic, 3 hours and up.

Watch your forearms. If they dry up, you're about to have a medical problem. Pinch the skin on the back of your hand. If it stands up, you're dehydrated.

Just a recent experience to show what can be done (this in no way says this should be attempted!). I did a 100 mile ride last week with 2 20oz bottles of water, one with carb mix the other with electrolyte tablet. I was in a good groove and didn’t feel the need to make any water stops over the 5.5hr or so duration and I rode a steady pace (66%). I also consumed 1000 calories (ride itself was 3600kj of work), so probably less than is advisable for others but works for me

It is different for everyone. It changes with weather, how hydrated you were before the ride, body type. To many factors to make a blanket statement.

I've never heard of permanent knee injuries from being dehydrated.

Yes, there can be a dietary component, but to make this statement that seems to trivialize urine color as an indicator is just false information.

There ya go.

People are different. Needs are different. Environments are different.

Find what works for you as it's unlikely to be the same for someone else.

Have some beet juice before your ride. That'll give you an interesting color.

A Vit B tablet will add some brilliance to the matter. :)

Really? First I've heard of it.

Source?

So why do you ask at a place that is going to be full of opinion? You won't find any less controversy here.

I don't drink the juice but I do add raw beetroots into my smoothie everyday. I definitely notice some reddish tinge after a bathroom break.

Urine color should be trivialized. It's old think silliness. As my cycling doctor says, "It's quantity, nothing to do with color." Remember that guy on here a while back who was drinking like a 1/2 gallon an hour off the bike, trying to get his urine clear? Very dangerous.

Have a good pee at least every 3 hours on or off the bike, all good. No pee, bad. I speak from doing a lot of doubles, brevets, and other long hard rides in the heat and in the mountains. It's pretty simple. If I come into a control and can't pee, I sit there and drink water until I do. That's not wasted time.

https://www.precisionhydration.com/b...-well-hydratedandThere's your message, OP.

B12, found in most multis, turns your pee kind of yellow-orange. Nothing to do with dehydration.

Heat stroke while riding can cause a bunch of injuries. Knee injuries, head injuries, arm and clavicle injuries. Rash.

Don't eat roasted beets within a couple days of a colorectal or prostate exam. Just sayin'.

Heat stroke and dehydration are not the same thing.

An interesting thing is that for the "Hour Record" attempts. They ride fast and hard. But, they don't drink water.

Oh, and here's why.

https://www.bicycling.com/news/a2817...-record-crash/

James MacDonald spilled water on the track, then later slipped on his own water. :bike2:

No, but related.

Dehydration may reduce one's body's natural cooling. And, of course, sweating and lack of fluid replacement can lead to dehydration.

I will say that with proper hydration, a reasonably fit cyclist seems to be able to maintain body temperature up into the mid 90's. Maybe even over 100° weather. Probably in a large part because riding leads to air movement which helps with evaporation. That is, if one is properly hydrated.

Well, I'm guessing your cycling doctor disagrees with The Mayo Clinic among other sources. To each his own I guess.

They say "a happy mountaineer voids clear" but if there's any disagreement I'll go with quantity every time.

There are people who weigh themselves before and after exercise in the summer, to measure fluid losses, and that's how much they'll aim to drink. Personally I drink when I'm thirsty, it works pretty well, the only downside is I'll be thirsty after I'm rehydrated and then I'll pee too much the next day.

drink the amount that works for you.

I used to habitually bring (and drink) two 24oz bottles on every ride, regardless of length. I noticed as I lost weight (and got fitter) that I was less thirsty. So much so that I sport just one bottle cage these days. My regular weekday rides (20-30mi) are with one 20oz bidon (tel que https://ellumbagworks.com/product/fundamental-bidon/) --about half of your 1 liter/30 km recommendation. Now that it's really hot (finally), I'll actually drink the whole thing and perhaps refill mid-ride. Rode an organized century at the beginning of the month, topping off at each aid station. Probably totaled 4-5 bottles for the 103 miles (~3 liters for the 165km). --Now during that same 103 miles I also went through 9 Hammer Endurolyte pills.

What you see as "controversy" can also be interpreted as "varies by individual."


This is one of those "do it because you feel good" things, not "do it because the internet said so" things.

Yes, there is that.

Yup, the pee test works for me. If clear I’m ok if yellow it could dehydrate a fellow. I tend to hydrate maybe too much but I’m in a hot climate so it is out of habit a good habit.

Ok, so I'm not the only one who didn't get the memo.

It kind of stands to reason that water is one of the many things between your joints, and knees are joints, so not drinking enough water cold be bad ... for your knees and nothing else.