Businessman Kevin O’Leary is probably best known for his starring role on the television program Shark Tank, where gung-ho entrepreneurs pitch their business ideas to a panel of investors.  So, it may surprise you that O’Leary has a rule that he will not hire workaholics.

“If you look at great managers, great investors, great entrepreneurs, you’re going to find a common trait: what they do with their spare time.”  O’Leary noted that these great leaders usually do something outside of work that “has nothing to do with business,” such as playing sports or doing something in the arts.  “You need balance in your brain,” O’Leary added.

Recent research backs O’Leary’s theory.  In the Harvard Business Review, researchers explained that leaders who felt recharged the next day had detached from work the night before.  Those who felt drained thought about work – or worked late – the night before.  Even employees noticed the difference.  The ‘more effective’ team leaders were the ones who had stopped thinking about work at home.

And O’Leary isn’t alone.  Microsoft co-founder Bill Gates often speaks about the importance of fostering a life outside of work.  Gates reads novels, biographies, and non-fiction books, saying this hobby has been a major contributor to his success.

What Can I Do?  Make a list of things you are passionate about and commit to doing them at night and on the weekends.  It may seem counter-intuitive that you can be more efficient and effective by working less, but in the words of self-development author Brian Tracy, “Just as your car runs more smoothly and requires less energy to go faster and farther when the wheels are in perfect alignment, you perform better when your thoughts, feelings, emotions, goals, and values are in balance.”