"I'm sure that's not a pretty sight," he allowed.
Gingrich appears to still be working on perfecting the power nap.
Earlier this month he drifted off, on camera, while waiting for his turn to address a live-streamed meeting of a pro-Israel lobby.
"I understand you have a panel," he told the moderator as he snapped open his eyes. "I look forward to any questions."
An awkward pause ensued while Gingrich waited for questions.
"Mr. Speaker, there is not a panel," the moderator informed him. "Please do continue, sir."
Gingrich may have done himself more good by staying up until 2 a.m. dancing with his wife, Callista, at a hotel lounge in Jackson, Miss., a few days later.
The former House speaker later pronounced it great fun, and called it a "two-hour vacation."
Early on, Gingrich caught grief for taking a couple weeks off the campaign to take his wife on a Mediterranean cruise, and he still gets home many weekends to rest and attend Callista's Sunday choir performances, but he's put in his share of late nights campaigning.
And that's when he's prone to loosen up and get a little punchy, producing what reporters call "late-night Newt" performances.
On one recent evening, Gingrich tested out possible bumper sticker and T-shirt slogans, such as "With Newt, Drill Here, Pay Less," and "Barack Obama, Pay More, Pay Weird."
Romney, for his part, savors the rare chance to sleep in his own bed.
"Oh, boy, we're headed home," he said earlier this month when the primary calendar gave him a pit stop in his home state of Massachusetts after two straight months on the road.
He knew it wouldn't last, though.
"Tomorrow, we wake up and we start again. And the next day, we'll do the same," Romney said. "And so we'll go, day by day, step by step, door by door, heart to heart. There will be good days. There will be bad days. Always long hours, never enough time to get everything done."
Maybe not enough time to wash his shirt. But, hey, Romney says at least he gets "a lot of frequent flyer points," for staying at all those hotels.
And on Romney's campaign bus, the candidate can count on a never-ending supply of one of his favorite comfort foods: peanut butter and jelly sandwiches.
Associated Press writers Brian Bakst in Minneapolis, Beth Fouhy in New York, Steve Peoples in Chicago and Kasie Hunt and Laurie Kellman in Washington contributed to this report.
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