Elon Musk says he sleeps his many hours, despite all the projects that are on his plate

In a wide-ranging interview with podcast host Joe Rogan, Elon Musk revealed in February that he manages to sleep six hours a night despite balancing his responsibilities across all of his companies.

Speaking on The Joe Rogan Experience, the SpaceX and Tesla CEO appeared to take Rogan aback when he discussed his work schedule.

“How do you have time? I never understand you in regards to the way you run multiple businesses simultaneously,” Rogan said. “I would think that something like [the SpaceX rocket] would require so much concentration — I would think this would be your whole being, trying to figure out how to work this.”

Musk responded by bluntly saying that he works “a lot,” adding that he normally works until 1 or 2 a.m. during the week. When Rogan then asked how much sleep the tech entrepreneur regularly gets, Musk didn’t hesitate to give a number.

“About six hours,” he said. “Not that crazy.”

Musk later admitted to an impressed Rogan that he had tried to sleep less but pointed out that “total productivity decreases” when doing so.

“I don’t find myself wanting more sleep than six,” he said.

The nearly three-and-a-half-hour interview seemingly touched on every possible subject — from what it would take for humans to live on Mars, to Musk’s concerns about artificial intelligence. At the beginning of the interview, the billionaire businessman even shared a fun fact, noting that he made Starship, the SpaceX rocket, “more pointy” after watching Sacha Baron Cohen’s 2012 comedy The Dictator.

“I thought it would be funny if we made the rocket more pointy, so we did,” Musk said, adding that the design had no effect on the rocket’s aerodynamics.

In addition to overseeing SpaceX and Tesla, Musk leads or works at three other companies: The Boring Company, Neuralink and OpenAI.

This article originally appeared in Entrepreneur.