This post has been updated.

It was hard to miss the sweat on the candidates’ faces Wednesday night during the Republican presidential debate.

The snarky comments about perspiration started not long after the debate began. Some thought it was worse than Richard Nixon's meltdown during his first debate with John F. Kennedy. Perhaps the sweat could solve California’s drought problem. Or maybe it was all a plot by CNN, which hosted the debate, to make the candidates uncomfortable, one of the many tweets that twitchy.com pulled together.

On Friday, Donald Trump said the room was “extremely hot, extremely hot for everybody sitting there and for the people standing.” In an interview with Kilmeade & Friends on Fox News Radio, he took a jab at one of his opponents. “Marco Rubio, I’ve never seen anybody sweat like that and you know a lot of these guys are serious sweaters, frankly but it was extremely hot in the room and extremely uncomfortable.”

The air conditioning was apparently on full blast at the Ronald Reagan Presidential Library, but part of the problem was that the debate stage was built on scaffolding three stories above ground level so the candidates would be level with the enormous backdrop, the Air Force One plane that Reagan flew upon.

Of course heat rises, and with 450 to 500 people in attendance and the candidates under hot television lights, those onstage were sweating from the outset, and campaigns complained.

The folks in charge of the GOP debates were not happy.

"It is a magnificent setting but it clearly didn't have adequate AC for the size crowd with the addition of lights, etc.," wrote Steve Duprey, an RNC national committeeman from New Hampshire and the head of the RNC's debate committee, in an e-mail. "The candidates were visibly perspiring and we need to make sure that doesn't happen again."

Still, standing for three hours under hot lights wasn't likely to make anyone even mildly dehydrated. “Unless they started out dehydrated to begin with, then that candidate may be more at risk for developing mild dehydration than someone who went in well-hydrated,” said Ryan Petering, a family and sports medicine physician at Oregon Health & Science University.

“The reason we sweat is to help get rid of body heat,” he said. Of course, if you’re nervous and your heart is racing, that triggers the body to sweat more.

Typically, people would have to lose 1 to 2 percent of their body weight to become even mildly dehydrated, he said. For someone weighing 200 pounds, that’s two to four pounds, "which is not a trivial amount of weight,” he said.

It’s not clear whether any of last night’s candidates took those temperature factors into account during their preparation.

Maybe for the next debate, they could take a page from Al Gore, who was so meticulous that he once demanded the practice room for a debate be cooled to the temperature of the hall and told aides to be sure to calculate for the warming effect of the audience.

Philip Rucker and Karen Tumulty contributed to this post.

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