He's lost more than 100 pounds, competed in four marathons and, last Saturday, ran seven miles in humid 85-degree weather before giving a speech -- for money, not votes -- in the Cayman Islands.
But for the most part these days, Republican presidential candidate Mike Huckabee finds himself bushed, bothered and slightly bewildered.
"Sometimes I'll wake up in the middle of the night at home and I don't know where I am," the former Arkansas governor said in a phone interview Sunday night from his campaign plane "somewhere between Chicago and Wisconsin."
If one unalterable truth about American politics has become even more true in recent years, it's this: Running for president can be really, really tiring.
Every election cycle has its poignant, not to mention loopy, episodes -- from Edmund Muskie's tears (or melting snowflakes?) in 1972 to Howard Dean's primal scream in 2004 -- when exhaustion gets the best of candidates coping with 20-hour days, bad food, frigid weather and clammy, anonymous motel rooms where the pillows are unfamiliar (George W. Bush carried his own) and sound sleep elusive.
But being tired has taken on new meaning during the condensed, heavily front-loaded 2008 primary season, as presidential candidates of both parties struggle with the kind of bone-deep fatigue once mainly associated with medical residents and new mothers.
This week, Sen. Hillary Rodham Clinton found her schedule to be particularly challenging.
She was supposed to start Wednesday with a stop in the border town of Brownsville, Texas, where Hispanic voter support is crucial if she is to win that state's primary.
But that plan was scrapped at the last minute, and, late Tuesday, after a rally in Youngstown, Ohio, she flew to New York -- arriving a little after 2 a.m. -- so she could attend several fundraisers in Manhattan earlier yesterday.
She then flew to south Texas, arriving around 4:30 p.m. for a rally in Hidalgo, in the Rio Grande Valley, followed by a second rally in Brownsville later last night.
"It's a marathon, and I think people thought it would slow down after Super Tuesday," said Carrie Giddens, former spokeswoman for the Iowa Democratic Party, now a Washington, D.C.-based communications consultant. "That has not proven to be the case."
Sometimes, sleep deprivation can help a candidate: Mrs. Clinton's misty-eyed moment in New Hampshire in January -- which staff attributed to a grinding schedule -- won her sympathy, especially among women voters.
Still, it's amazing what four hours of sleep will do to an otherwise intelligent politician.
Sen. Barack Obama claimed 10,000 people perished after a tornado in Kansas -- the actual death toll in the twister hitting Greensburg in 2007 was 12. Mitt Romney declared he would "never remember Iowans." Mrs. Clinton noted that some 300 people left outside in Iowa City had "literally" frozen to death. When Mr. Huckabee, who watches his diet carefully, confronted some steel machinery at an Iowa factory, he told the crowd it looked like a giant pizza server.
"It was the only thing I could visualize," he said.
No one is forcing the candidates to live this kind of life -- or for that matter, the equally exhausted campaign aides and press corps trailing in their wake.
"I knew what I was getting into," said Jonathan Martin, a 30-year-old reporter covering Republican candidates for Politico.com. Life in "the bubble" of a presidential campaign can be an adrenaline rush but also very tough on the body.
"If you don't have any discipline, you'll find yourself chomping away," said Mr. Martin, who admits to having gained weight despite adhering to a running schedule while on the road.
"I know one reporter who, now, after many campaigns, will simply not eat cold sandwiches. I myself have become a connoisseur of hotel gyms," he added, noting that the one at the Des Moines Marriott "is particularly good."
Asked to analyze which candidate seems the most fit -- or the least -- Dr. Vonda Wright, an orthopedic surgeon at the UPMC Center for Sports Medicine, demurred.
"They may look OK but we don't know what's going on under those clothes. Barack Obama may be skinny as a board, but for all we know he could be totally out of shape, whereas Mike Huckabee has a midlife spread but would probably win on fitness, hands down. And Hillary, I don't know that she's been an athletic woman. I don't know that it's ever been a priority for her."
For the record, Mrs. Clinton drinks lots of tea, but no matter, added Dr. Wright. "This kind of lifestyle is unsustainable for the years they're campaigning."
And no matter how much you exercise, studies show you'll gain weight if you don't get enough sleep, added Dr. Charles Atwood, a pulmonary and sleep medicine physician at UPMC.
"Sleep deprivation has an effect on the hormones that govern appetite," he said. "You tend to crave foods that are salty and have a higher fat content, and instead of reaching for the carrot sticks, you're reaching for the potato chips."
Then, there's the voice, something that was noticeably troubling Mrs. Clinton in Ohio this weekend.
"All of these presidential candidates are going into vocal danger zones, loud environments with 6,000 people listening to them and speaking over background noise on a regular basis. It's amazing they haven't lost their voice altogether," said Jackie Gartner-Schmidt, a speech pathologist and associate director of the University of Pittsburgh Voice Center.
"A lot of time they don't have to be using their voice at all," she added. "At those big rallies, you can smile, laugh, be animated in every other way, but people can't hear you anyway, so you shouldn't be shouting and yelling."
Candidates have different ways of coping with a campaign's physical demands. John Edwards' stamina was legendary -- he visited 99 counties in Iowa and reporters still talk about one marathon 36-hour bus trip. Rudy Giuliani, on the other hand, kept a relatively leisurely schedule in Florida, averaging about three events a day until the final week and staying in four-star hotels.
Still, it was the former New York mayor who was rushed to the hospital while on the campaign trail complaining of a severe headache -- something his staff later attributed to the Mr. Giuliani's intense work ethic.
"He actually got fewer hours of sleep than the rest of us," said Elliott Bundy, Mr. Giuliani's former press spokesman.
"Often there would be days when we were on the plane coming to and from events and it was a contest between the staff to see who could pass out fastest, and we'd wake up and he'd be working."
There is, perhaps, another downside to the frenzied presidential nominating process: increasingly scripted performances by dead-tired candidates afraid to be spontaneous or authentic while complying with the demands of the 24-hour news cycle.
"In years past, those guys could have made one of those gaffes and not have it reported," noted Politico.com's Mr. Martin. "But now, cable news and the networks have these 'embeds,' reporters with a camera at every public event in every state, so the candidates can't escape the scrutiny. And that has, perhaps, made them hesitant to express themselves in public, which is too bad."
"These guys are only human," added Ms. Giddens, the Washington communications consultant.
"Everyone is going to confront their demons when they haven't slept. It's just human nature, and it's something we all need to remember the next time one of them flubs a line or loses it."
Mackenzie Carpenter can be reached at firstname.lastname@example.org or 412-263-1949.