I don't know if this s true but I heard because of their short hair pit bulls or their one coat (?) that they are very susceptible to the heat and cold and have a harder time of adjusting than other dogs.
Also someone told me to wet their paws down when they take a break to cool down.
Their short hair allows more sun to hit them. I'd say sun burn is more likely to happen. In cold weather I'm sure they have a disadvantage but it would help not to have all that fur in the summer.
Wetting down the belly and groin is the first place people should start when combating heat exhaustion. Then placing them in the car in front of the air conditioner and getting them to the vet in the shortest time possible is recommended.
When my girls are hot I always poor water on their belly and groin area to cool them down. Even if they aren't over heating. Like I said, I've come close to losing both my dogs to the heat so I'm a bit paranoid about it.