By David Gelles, et al. write in the New York Times,

In the interview on Thursday, Mr. Musk alternated between laughter and tears.

He said he had been working up to 120 hours a week recently—echoing the reason he cited in a recent public apology to an analyst whom he had berated. In the interview, Mr. Musk said he had not taken more than a week off since 2001, when he was bedridden with malaria.

“There were times when I didn’t leave the factory for three or four days—days when I didn’t go outside,” he said. “This has really come at the expense of seeing my kids. And seeing friends.”

Mr. Musk stopped talking, seemingly overcome by emotion.

He turned 47 on June 28, and he said he spent the full 24 hours of his birthday at work. “All night—no friends, nothing,” he said, struggling to get the words out.