Apple CEO Tim Cook’s daily routine starts with waking up at 4 a.m. and reading customer emails

Once he’s at work, Cook hosts marathon meetings.

The Journal’s 2014 article reported that Cook’s weekly operations meetings could last five or six hours and that he was known to relentlessly question employees.

“‘Talk about your numbers. Put your spreadsheet up,’ he’d say as he nursed a Mountain Dew,” the Journal wrote.

Cook has since said he’s a big fan of Diet Mountain Dew, though Apple’s campus doesn’t stock it.

Mike Janes, the former head of Apple’s online store, told CNN Money in 2008 about an afternoon meeting with Cook.

“A number of us had tickets to see the Mets that night,” Janes said. “After hours, he was still drilling us with question after question while we were watching the clock like kids in school. I still have this vision of Tim saying, ‘Okay, next page,’ as he opened yet another energy bar. Needless to say, we missed the Mets game.”

He also has no problem sitting in silence until he gets a suitable answer.

“In meetings, he’s known for long, uncomfortable pauses, when all you hear is the sound of his tearing the wrapper of the energy bars he constantly eats,” CNN Money reported.

As a result, the Journal said, employees had learned to be prepared, cramming for the meetings as if they were tests.