Training & Nutrition - What's the poop on sweat?

Let's say you do a 3 hour ride in 85+ degree heat, high humidity if that factors in at all. You drink 2 liters of water. If it could be measured (american non-metric please), about how much of that get's sweated during the ride? This is 3 hours of actual riding. Any ideas?

I'm no biologist but I doubt it can be measured - you might be able to calculate an average, but people seem to sweat at different rates, and you'd need to factor in size, weight, fitness, exertion etc.

Weigh yourself before you ride, then weigh yourself after you ride. Then add to your "post-ride" weight the amount that you drank (1 liter = 1 kilogram = 2.2 pounds). Most of the difference between before and after will be lost water, i.e. sweat. I don't know whether we're talking 70%, 80%, 90%, or more, but I have read that the vast amount of lost weight will be water. Although Richard is certainly right that it is pretty hard to measure, given all the factors involved.

As a rule of thumb, you should weigh about the same after a ride as you do before a ride. If you don't, you are probably not drinking/eating enough.

At the risk of sounding snotty, I have to point out that you ask for American mesurements, but you give the water in liters (metric). Since 1 liter = 1 kilogram, metric is much easier to work with in cases like this.

Little known fact: the U.S. congress passed a resolution (not a law) in the 1930s which said that metric would be its official measurement system. Not that anyone listened.

Cheers,
Jamie

Hey, they TRIED! I grew up during the Carter administration, when they started requiring everything to list metric as well as standard measurements, as well as making us watch 'Metric Man' at school.

Then the conservatives seized control of the government again. :p

BTW, remember that you also lose water through your breath.

Yep, they tried indeed. I guess we're a stubborn bunch and in view of the way my question was phrased (as Jamie pointed out) a little confused.:confused:

Originally posted by jmlee
Weigh yourself before you ride, then weigh yourself after you ride. Then add to your "post-ride" weight the amount that you drank (1 liter = 1 kilogram = 2.2 pounds). Most of the difference between before and after will be lost water, i.e. sweat. I don't know whether we're talking 70%, 80%, 90%, or more, but I have read that the vast amount of lost weight will be water. Although Richard is certainly right that it is pretty hard to measure, given all the factors involved.

As a rule of thumb, you should weigh about the same after a ride as you do before a ride. If you don't, you are probably not drinking/eating enough.

At the risk of sounding snotty, I have to point out that you ask for American mesurements, but you give the water in liters (metric). Since 1 liter = 1 kilogram, metric is much easier to work with in cases like this.

Little known fact: the U.S. congress passed a resolution (not a law) in the 1930s which said that metric would be its official measurement system. Not that anyone listened.

Cheers,
Jamie

Remember to subtract the weight of all the flies sticking to your sweaty legs, arms, face etc. Or is it just me that happens to :)

So, what I wanna know is, if someone living in the U.S. were to "go metric", which for us entails primarily setting our bike computers to metric, would that be an act of patriotism or rebellion?

Cheers,
Jamie

Well, if you wear lycra and commute to work on your bike, people would probably accept your using the metric system as just another facet of your insanity. :D

Originally posted by oceanrider
Let's say you do a 3 hour ride in 85+ degree heat, high humidity if that factors in at all. You drink 2 liters of water. If it could be measured (american non-metric please), about how much of that get's sweated during the ride? This is 3 hours of actual riding. Any ideas?
I don't know! :D

But here's my rule-of-thumb, open to revision upon gathering new information--

DRINK, DRINK, DRINK. If I drink too much, there are only three problems I have to face:

1) Losing minerals--these can be easily replaced, as long as you know it's important to do so.
2) Stomach too full to perform properly--oh well, that will fix itself.
3) Having to pee--this won't fix itself, but a little creativity helps. :p

So, in my opinion, it's really better to drink too much than not enough.

If you're from Texas, converting to metric could get you in deep doo doo :(

Of course you could fudge the issue like we do - everything is now sold in metric units apart from beer which is still sold by the imperial pint, and whilst we (well those odd British citizens who insist on driving ;)) buy petrol ('gas') by the litre but drive in miles...

Personally I mix and match between centimetres and iches, feet and metres etc. but I've never got the hang of temperature in anything but centigrade.

What made me curious about this subject was the fact that I was out on the bike for around 4-1/2 hours yesterday. It was a wonderful solo adventure that was only supposed to be around a 15 mile ride. Anyway, I filled up my camelbak before I left the house in the morning and when I returned, I still had not peed nor did I have the urge to. I even got a refill when I ran out of water and still had around 40 minutes of actual riding left. The best I could figure is that I sweated it out.

I drink a lot before I ride and I try to drink a lot during my rides--and I am getting better and better about this. I have never had to pee while riding. Out of curiosity, I weighed myself before and after a ride a couple of times. I almost always come back a little lighter. I am sure that most of the loss will be sweat, some of it will be lost moisture on the breath (as was pointed out).

By the way, after nearly 2 years of living in Europe I am fully accustomed to thinking metric--to the point that miles seem much too long to me now (when I am driving in the States). But, like Richard, the hardest for me has been temperature. I am now getting used to it, but 20 degrees celcius just doesn't mean as much to me as 68 degree Fahrenheit. But I do like the ring of having ridden 100 kilometers better than having ridden 61 miles.

Cheers,
Jamie

In reply to Inkwolfs earlier post;thank God the conservatives rescued the government from Jimmy Carter. Nice man but an awful president!

take a shower weigh yourself naked, go ride measure your water intake, get home take a shower weight yourself subtract water consumed during ride

http://www.allaboardtoys.com/assets/product_imagesm/PK-3226.jpg

But here's my rule-of-thumb, open to revision upon gathering new information--

DRINK, DRINK, DRINK. If I drink too much, there are only three problems I have to face:

1) Losing minerals--these can be easily replaced, as long as you know it's important to do so.
2) Stomach too full to perform properly--oh well, that will fix itself.
3) Having to pee--this won't fix itself, but a little creativity helps. :p

So, in my opinion, it's really better to drink too much than not enough.

Dehydration is a whole lot less deadly than hyponatremia. If you've ever had the latter, you wouldn't be so casual about how much you drink. I've seen it, I've had it, it sucks. On a hot ride, you can blow through your body's stores of electrolytes in a few hours.

http://www.geo-outdoors.info/hyponatremia.htm

Dehydration is a whole lot less deadly than hyponatremia. If you've ever had the latter, you wouldn't be so casual about how much you drink. I've seen it, I've had it, it sucks. On a hot ride, you can blow through your body's stores of electrolytes in a few hours.

Hyponatremia and potassium deficiency are both bad... but if half of what you drink is gatorade and half is water, you should do fine on potassium/sodium/water balance.