banerjek

Last night, I significantly extended my commute home. Carried two large bottles of water but it was pretty inadequate. By the time I got home, I was feeling cold despite the fact temps were in the 90's -- living in Oregon has made me a real idiot about hydrating adequately in hot weather.

Anyway, I weigh myself just for the hell of it, and I was 6 lbs lighter than I was in the morning. I figure the scale is malfunctioning because I reweighed myself twice and got the same value. After drinking plenty of water and milk over the course of the evening, I was down about 1/2 lb from the morning. Next day, I'm back to my normal 138.

Can you actually lose that much in water in one ride, or is there a better explanation for what I saw?

666

Yep, you can easily loose 2% of your body weight. Much beyond that and you're looking at serious dehydration, though.

patentcad

My riding weight in the summer ranges from 168-175lbs. I have dropped as much as 8lbs on 4+ hour strenuous rides on hot days. That's not too unusual for athletes in hot conditions. I rarely lose more than 3-4 lbs, but every now and then it spikes. Purely water weight of course, it's always mostly back by the next day.

jimblairo

I weigh in the 220-230 range and on long hard rides on very humid days I can drop 6 to 8 pounds while drinking at least 4 liters of water. By midnight it is back on.

soccerun8728

I ran cross country in high school and on a 90+ degree day I lost 8 pounds of water and my friend lost 10. Only one of our teammates passed out during the workout. We had one of those 10 galloon water coolers and about 10 guys emptied it in about 90 minutes.

e2py

Here's food for thought on this topic:

1 gallon of water equals 8.33 lbs.

Fredly00

I used to work The morning shift at UPS, during the shift I would regularly
loose 5-6lbs, I would drink at least 64oz oz water during a 5hr shift...
by night time I would be back to my regular weight... although I also lost
20lbs of fat in a 6 mo period of time.

So yea its very possible.

Snicklefritz

There was one year in the TdF (I don't recall which) where Lance lost a lot of weight due to dehydration and was in danger of some serious problems...I seem to recall it being something around 13 lbs but that seems a bit high.

etz

If I don't drink while riding I lose a kilo (2.2 lbs) an hour. Summer or winter. Fast or slow.

slacker00

~8 lbs in 2 1/2 hours for me. I replaced ~2 1/2 lbs of it during the workout, but that wasn't enough. I was close to passing out after that workout. I couldn't even force myself to drink water at the end, just tiny sips. I weigh 180 lbs.

Lesson for me: Don't mess around with dehydration, don't work out in high temps at high intensity. Be careful.

VT to CA

Depends entirely on your personal physiology.

urodacus

the usual formula for water replacement is 150% of the weight you lost during the ride. if you lose 4 kilos, which i have occasionally done after a day's ride in the humid heat here, then you must drink 6 litres in the next day at least.

if you guys would only use metric measurements, you'd find it a bit easier to calculate these things!

1 liter of water is 1 kilo of weight, exactly (by definition).

and if you forget to rehydrate enough, you'll end up looking like my mummy.

flaco

A pint is a pound. It's not that hard.

So, if you lose five pounds on a ride, drink five pints of beer immediately.

BetweenRides

+1!

orcanova

Umm...lite water weighs almost half that...

va_cyclist

I weighed myself just before a 50-mile, 90-degree ride last weekend, during which I consumed 3 20-oz. bottles. At the end of the ride I was 4 pounds lighter. If each bottle is about 2 pounds, that's a 10 lb. evaporation loss.

littlewaywelt

Once you lose 2% of your body weight in water loss your performance will drop off substantially.

One of the interesting things about cycling is that it's harder to realize how much water you lose because you don't get really wet as the air evaporates the moisture so quickly. When running, I find it's much easier to know how much water you're losing.

Cassave

Um, using the 150% formula, that would be 7.5 pints of beer.

bkriete

Each bottle is 1 lb, 4 oz. Not two pounds. 16 ounces = one pound.

Ironic Mullet

Still not as light as dehydrated water.

stapfam

On the TDF- I heard a rider talk about moisture loss and he said that if you do not put on half the weight loss of a ride- in one hour after finishing the ride- Then the next days performance would be way down.

Blue Jays

Having dehydration chills in 95* Fahrenheit weather is a very uncomfortable experience. A good technique I've had to is to very carefully prehydrate before the start of a ride coupled with adequate intake during exercise.

flaco

Oh, right. Better make it 8 just to be safe.

Tappets

personally lost 6 pounds on a hot day 100 miler. i was still drinking lots of water and gatorade and would stop for an occasional cold pepsi or coke. it didn't take long to get back up to my normal weight.

dpr

I would be interested to hear every ones approache to pre-hydration if any. Personally, I drink a pint of water just before going to bed the night before a moderate to long ride (50 miles +). Then in the morning ill drink a pint or two in gradually over the two / two and a half hours between waking up and getting on the bike.