The world’s richest man has said that he sleeps for just about six hours a night. Elon Musk who is CEO of aerospace company SpaceX, electric car company Tesla, and neurotechnology company Neuralink, as well as founder of The Boring Company, which constructs tunnels, certainly has a lot on his mind each day

According to the World street journal, the billionaire has said that in the past that he worked hundreds of hours a week and will sometimes even sleep on the floor under his desk at Tesla.

“I work a lot,” Musk told Joe Rogan during the latest episode of “The Joe Rogan Experience.” “Normally, I’ll be in meetings at work until 1 or 2 in the morning. Saturday [and] Sunday, usually not, but sometimes.”

In an interview with Rogan, Musk said he gets “about six hours” of sleep, “I tried sleeping less, but then total productivity decreases,” he said. “I don’t find myself wanting more sleep than six [hours].”

“There were times when, some weeks … I haven’t counted exactly, but I would just sort of sleep for a few hours, work, sleep for a few hours, work, seven days a week,” Musk told Kara Swisher in November 2018, recalling his effort to ramp up Tesla Model 3 production. “Some of those weeks must have been 120 hours or something nutty.

Musk admitted that schedule was not healthy, telling Swisher that he had “burnt out a bunch of neurons.”

“No one should put this many hours into your work,” he told Axios in 2018. ”It’s not recommended for anyone. You’re gonna go a little bonkers if you work 120 hours a week.”