ANALYSIS: President Trump vows to stay 'fresh' on grueling Asia trip Trump says staying fresh on the road 'won't be a problem for me.'

TOKYO -- President Donald Trump loves superlatives: Biggest, best, highest, strongest -- all words he frequently sprinkles into his comments about policy and politics.

White House officials are now picking up his habit when talking about this trip to Asia, repeatedly emphasizing that this is the longest trip to the region by an American president in more than a quarter of a century.

Thirteen days, five countries -- it’s a grueling schedule for President Trump and his staff.

And don’t forget the time zone difference. Most of the president's work will be happening 12 to 14 hours ahead of what the clock says back in Washington.

The presidential travel record the White House keeps citing was set by President George H.W. Bush in early 1992. But that trip became infamous when Bush fell ill during a state dinner with Japan’s prime minister, threw up and collapsed.

President Trump’s first trip overseas in May was another long haul. On Day 2 of that 10-day trip, a White House official explained a verbal slip by the president by acknowledging that he was already exhausted.

But on Air Force One heading to Japan Sunday, the president brushed off questions from reporters about how taxing this Asia swing will be.

“It is grueling, they tell me," he said. "But fortunately, historically that has not been a problem for me."

President Trump said he could have divided the schedule into two trips, but with the two summits -– APEC and ASEAN -- it made the most sense to do it as one big one.

Trump was asked by reporters on Air Force One how he plans to stay fresh.

"I’ll let you know if I don’t stay fresh," he said. "If I don’t stay fresh, you’ll be the first to tell me. I’ll stay fresh."