In a candid interview, Elon Musk opened up about his demanding schedule. (Wolfgang Kumm/EPA)

Elon Musk is a notorious workaholic. As the chief executive of SpaceX and Tesla has long made clear, he doesn’t really need much vacation. He’s described lounging on the beach as “the worst,” and something that would leave him “super-duper bored.” He joked in a recent biography that “vacation will kill you,” after recounting a trip that left him with a malaria infection.

This makes Musk’s recent remarks to a Danish television station so surprising, and a reminder that long hours can grind down even the toughest and more passionate workers.

“My priority right now is to try to add some more management bench strength to Tesla in particular so that I can take a vacation,” Musk said in an interview published Sunday. “In the last 12 years I’ve only tried to take a week off twice.”

An emotional Musk grew misty-eyed during parts of the interview, and reflected on the toll that running SpaceX and Tesla has had on him.

“Creating a company is almost like having a child,” Musk said. “It’s almost like, how do you say your child should not have food?”

“So once you have the company you have to feed it and nurse it and take care of it even if it ruins you?” asked his interviewer.

“Yeah,” said a misty-eyed Musk.

After a long pause, Musk was asked how he got through the 2008 financial crisis.

“Yeah,” said Musk with a shake of his head. “Can we just break for a second?”

Musk was strikingly more emotional and vulnerable than in most interviews. Gone were the usual efforts to present himself as superhuman yet light-hearted. At one point Musk appeared close to tears and wiped his eyes. At another point he acknowledged he has questioned why he submits himself to all the risks of running stressful companies such as SpaceX and Tesla. (Not to mention being the chairman of SolarCity.)

“I have to say at times I’ve wondered,” Musk said with a laugh. “It’s actually been a very difficult journey I have to say. But I think there are certain important things that we must do in order for the future to be good. We must have sustainable energy. If we don’t have that the future is going to be terrible.”

Musk seems resigned to the fact that for now at least, he must work like a maniac. He can’t afford to vacation.

“The first time I took a week off the Orbital Sciences rocket exploded and Richard Branson’s rocket exploded. In that same week,” Musk said. “The second time I took a week off my rocket exploded. The lesson here is don’t take a week off.”

Related: The 22 most memorable quotes from the new Elon Musk book, ranked