Self-made billionaire Mark Cuban's morning routine is simpler than you might think.

"A lot of people ask about my daily routine, and you're going to be shocked," Cuban told People in a video interview that published last week. "[I] look at my phone or I'm looking at a laptop and I'm on there, eight, nine, 10 hours a day."

Cuban prefers when people get in touch with him with a quick sentence or two, rather than him wasting hours in meetings or on phone calls, he said.

His daily routine starts when he wakes up — between 6:30 and 7 a.m. — and responds to emails for an hour before getting out of bed, he told comedian Trevor Noah on a January episode of the "What Now?" podcast. The early-morning organization helps keep him productive throughout each day, said Cuban.

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It's partially a privilege, Cuban admitted: He was initially attracted to entrepreneurship so he could control his own schedule. His day job today involves running one of the companies he founded, a pharmaceutical startup called Cost Plus Drugs.

"The whole value of being in this position is just being able to control your time," Cuban, 65, said. "It's the one asset you can't control."

Starting your day with emails and texts isn't always beneficial to your mental health, psychology researcher Nicola Hughes told CNBC Make It in 2018. But for Cuban, his schedule and communications are streamlined through his inbox, which helps him prepare for the day and cut down on unnecessary calls and emails, he said.

Productivity isn't always about waking up early

Some high-profile business leaders wake up much earlier than Cuban. Former PepsiCo CEO Indra Nooyi arises around 4 a.m, she told Fortune in 2012. Apple CEO Tim Cook reportedly wakes up at 3:45 a.m., and works for an hour before heading to the gym.

Waking up early can give you some alone time, so you can set goals, exercise or complete personal tasks without distractions. Just 20 minutes can set the tone for your entire day, psychologist Joel Dyoskin told Make It in 2022.

But only 5% of CEOs actually get up around 4 a.m., with over two-thirds waking up before 7 a.m., according to a 2022 Inc. survey. That may be due to a simple fact, experts say: How early you wake up is a lot less important than how much sleep you get and how you use your morning time.

Sleep scientists typically recommend between seven and nine hours of sleep per night for peak physical health, mental health and productivity. Consistency helps, too — you're likely to feel less tired if you get up and go to bed at similar times every day.

Cuban, who once said he get roughly seven hours of sleep per night, keeps his routine consistent, he told Noah. After he gets out of bed, he eats breakfast, works out and checks his email on his phone again.

"Rinse and repeat," said Cuban.

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank," which features Mark Cuban as a panelist.

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