"Exhaustion," Leno told People, a bit embarrassed about having to cancel two shows. In the interview, Leno reportedly shook his head and joked that the affliction was "like a rich person's condition."
"Poor people that work – they don't get exhausted," he said. "Only rich people get exhausted."
Still, Leno said that his hectic schedule forced him check himself into a Burbank hospital -- Besides the talk show, the 59-year-old entertainer hits the road 160 days a year doing stand-up, and maintains writing gigs for London's Sunday Times, Popular Mechanics and a British magazine called Octane.
When Leno returned to the "Tonight Show" set last week, he made up a few sexier reasons to explain his absence.
"What happened was – and I think this was a mistake – I ate a raw pig a friend brought back from Mexico," was one of his excuses.
Leno -- who moves to prime-time in the Fall after Conan O'Brien takes the "Tonight Show" reins -- also joked about waking up in the hospital to find Conan smothering him with a pillow.
Don't worry Jay. We got your back.