With the dehydration and replenishing it pretty much evens out. Perhaps though, they use catheters.
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I have heard some just go in their pants. Seriously.
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They don’t.

Use your imagination.
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They sweat a lot and don’t need to pee and if they do they can just whip it out during a caution, I know Jr did it a long time ago
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no joke they pee themselves… last year there was radio trasmission between junior and tony eury and junior wanted to know how much longer they had cause he had to pee and tony told him just go and junior wouldn’t because it was a new suit… no joke it was a riding with junior via foxsports.com
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Some of you are funny. Sweat and urine are not the same thing!! Sweating is to cool the body, the bladder has a totally different function by removing toxines from the body. Some hold it and some have urine bags. Not uncommon.
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ummm,call to Speedy on tv.People know nothing. WE GO REST AREA AS NASCAR DRIVERS DON’T! WE KNOW NOTHING! ASK SPEEDY!
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I believe that nascar drivers drink limit to drink. i notice on pit stop.

Of course there’s the sweating. If you sweat alot, you don’t urinate as often. Its part of dehydration. Like you said though, they try their hardest to stay as hydrated as possible. That’s why their racing suits have an area in the groin that is super absorbent. Like another person said, they literally just pee their pants if they have to.
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I believe a couple years ago they asked Jeff Gordon that question on one of his specials he’s had over the years. He said that because it gets so hot in the cars, and with all the protective equipment they wear, that you sweat out any fluids you have taken in. That’s also why all the drivers have the water or gatorade in the car to drink, so that they don’t become dehydrated.
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A lot of drivers have said they don’t drink more than they have to before a race. Then when they drink a lot during the race, they’re usually able to hold it.
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the drivers will take in enough fluids before a race to keep themselves from dehydrating in the beginning of the race and then before they get into the cars many of them will do one last run to the bathroom so that they can hold more in thier bladders. yes when they have to go though and they are in the middle of a race, they will just go in the car. Granted that doesn’t always make for a nice surprise back at the shop for the guys after unloading the car. If you are even at track level in the pits for a race you can dehydrate. I have while working and i was drinking a 12 oz bottle every half hour of water. It’s really about preparing the body before ever getting to the track and then staying hydrated at the track for these guys.
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