Sleep researcher Christopher Barnes tells CNN that sleep-deprived managers exhibit less emotional self-control. That makes them more likely to behave abusively toward subordinates, which in turn can reduce workplace engagement.

Yet those are the effects that regularly getting less than 7 to 9 hours of sleep a night can have. An oft-cited study found that a person who is awake for 19 or 20 hours (i.e., someone who sleeps 4 to 5 hours a night) performs tasks like someone who is legally drunk. Another study found if you sleep 6 hours a night for 10 days, you will be as impaired in performance by day 11 as someone who pulled an all-nighter.

Sleep researcher Christopher Barnes, who teaches management at University of Washington’s Foster School of Business, has done studies that found sleep-deprived managers exhibit less emotional self-control. That makes them more likely to behave abusively toward subordinates, which in turn can reduce workplace engagement.

“Are CEOS who get 6 hours of sleep performing optimally? No, they’re not,” said neuroscientist Matthew Walker, author of “Why We Sleep.”

“And it’s not just about effectiveness, it’s about efficiency too. When you’re underslept you’re so inefficient. Why try to boil water on medium heat when you can boil it on high?”