JERUSALEM >> He stifles yawns. His eyes narrow. And ultimately, when he garbles part of his speech, an aide explains that President Donald Trump is “just an exhausted guy.”

It was only second day of an eight-day trip that includes four countries, a city-state (the Vatican) and an occupied territory (the West Bank). By the third day, in Israel, Trump was blinking through an appearance with Prime Minister Benjamin Netanyahu.

It’s the kind of punishing trip — lots of important people pontificating in windowless rooms, up to seven time zones away — that would tax anyone.

But Trump, at 70, is the oldest man to assume the presidency. He also is a noted homebody, who apart from the White House, seldom sleeps away from Trump properties or dines outside Trump restaurants. Whether at Trump Tower or in the Oval Office, he works at desks just steps from his bedroom.

For all that, the trip has mostly been a plus for the president during a particularly tough patch back home.

The nettlesome news media have been cordoned off. The FBI investigation is an ocean away. His Twitter posts are relatively tame. He has been honored with sword dances, lavish dinners and praise invoking Abraham Lincoln or lauding him as “capable of the impossible.”

“I agree,” Trump responded.

Trump has grown a bit dough-eyed through it all. But he is hardly the first president to grow road-weary. Bill Clinton got cranky. Ronald Reagan got sleepy. And George H.W. Bush got sick.

Trump started his overseas trip odyssey with a sleep deficit. It was 2:42 a.m. in Washington — 9:42 a.m. in Saudi Arabia — when Air Force One landed in Riyadh Saturday.

The president had slept barely a wink, according to Reince Priebus, the chief of staff. He said Trump spent the long flight — 12 hours and 20 minutes — meeting with staff, reading newspapers and working on a major speech.

White House officials had considered a daytime flight for Trump’s maiden trip. That would have guaranteed him a night in a hotel room, and sleep, before his first round of meetings with foreign leaders.

But then the trip — initially scheduled as a three- or four-day jaunt to Belgium and Sicily to attend the NATO and Group of Seven summits — grew more ambitious as aides weighed in.

Trump has run more than an hour behind schedule, pushing events back and even canceling one, a Twitter forum Sunday night in Riyadh. Dozens of youthful attendees left the convention hall when Trump’s daughter Ivanka took the stage instead.

Asked later that night to explain why Trump had deviated from the prepared remarks of his keynote speech in Saudi Arabia, alternately referring to “Islamic” and “Islamist” extremism when the text stipulated only the latter, one administration official explained it rather bluntly: Trump was “just an exhausted guy.”

Pockets of downtime in the schedule evaporated as meetings ran long and logistical complications arose.

The admission of Trump’s fatigue is potentially problematic given that he has long boasted about his stamina, emphasizing each syllable to imply his boundless energy.

During the campaign, moreover, he publicly mocked his opponents as weak or tired.

Jeb Bush, an early front-runner for the Republican nomination who was known to keep a dizzying pace as governor of Florida, became “low-energy Jeb.”

Hillary Clinton, the Democrat who traveled the world relentlessly as secretary of state, was derided for keeping a modest schedule and falling ill with pneumonia late in the campaign.

“She’s supposed to fight all of these different things, and she can’t make it 15 feet to her car, give me a break,” he said at one rally.

Trump’s free-wheeling rallies energized him through some of the lower moments of his improbable campaign. Even in office, his staff has sent him to arenas to buck up his spirits.

But foreign trips, with teleprompter speeches and tedious listening sessions, are different.

“I was astounded when I first saw the Trump schedule” of his first official overseas trip, said Marcia Hale, a senior White House adviser to President Bill Clinton who helped plan some foreign trips and often accompanied him.

Clinton, who was 46 when he was inaugurated, would get tired by the end of major foreign trips, Hale said. Rather than nod off, he could get testy.

On one trip early in his presidency, he scolded staff when a final stop in Hawaii — meant as downtime — morphed into a late-night meet-and-greet with local dignitaries.

Reagan, who was 69 when he took office, was more successful at building in downtime. Once, on his way to China in 1984, he stopped in both Hawaii and Guam to help ease the shift in time zones.

His wife, Nancy, kept a firm eye on whether the staff was making too many demands on the president.

“She never got involved with policy but she did look out for his schedule,” said Craig Shirley, a Reagan biographer. “Where are you going? How long are you going for? What stops are built in to keep him rested and fresh?”

That attention did not prevent a problem at the Vatican in 1982, when Reagan was seen shaking his head to avoid nodding off during a meeting with Pope John Paul II.

But George H.W. Bush, who was 64 when he took office, had arguably the most infamous case of presidential travel fatigue.

In 1992, during a state dinner in Tokyo, he suddenly grew pale, tumbled in his seat and vomited in the lap of then-Prime Minister Kiichi Miyazawa. Reports at the time blamed the episode on stomach flu or gastroenteritis.

The Japanese public was highly sympathetic when the scene was captured by TV cameras.