Although he has a portfolio with hundreds of companies to tend to, billionaire investor and “Shark Tank” star Mark Cuban is at a point in his life where he can get a good night’s sleep.

Most nights Cuban gets “about 7 hrs [of sleep]. Less on others,” as he said during a Q&A via media company The Boardroom’s Twitter account on Tuesday.

And he takes “Dad naps on weekends when I can,” he tweeted. 

In 2017, Cuban told Thrive Global podcast that he watches NBC’s “Law & Order” to wind down before bed and sets the television to turn off automatically.

“Maybe it’s a bad habit,” he said. “I think it’s an old habit that I just haven’t gotten rid of. Where, when my mind was racing so much and I needed to turn off and couldn’t, it was a distraction. When I was thinking about work all the time. If there was something else on, just to distract.”

He also said he uses a fitness tracker to monitor how well he slept.

Cuban isn’t the only billionaire that prioritizes sleep.

Microsoft co-founder Bill Gates gets at least seven hours of sleep each night, although he pulled all-nighters at the beginning of his career.

“I realize that my all-nighters, combined with almost never getting eight hours of sleep, took a big toll,” Gates wrote in a December blog post. He also likes a “short midday nap” before 3 p.m.

Amazon CEO Jeff Bezos, on the other hand, needs a little more rest each night.

“Eight hours of sleep makes a big difference for me, and I try hard to make that a priority,” Bezos told Thrive Global in 2016. “For me, that’s the needed amount to feel energized and excited.”

The billionaires are on to something: Those who regularly get seven to eight hours of sleep are more productive than people who get six hours of sleep, the American Academy of Sleep Medicine found. The organization recommends that adults get seven hours of sleep or more each night.

Originally published on CNBC.com