One of the most important keys to success, according to both Sheryl Sandberg and Arianna Huffington, is getting enough sleep.

The two women appeared onstage at Davies Symphony Hall in San Francisco Thursday to discuss the importance of being well-rested, gender equality in corporate America and the need to change the definition of success — the theme of Huffington's latest book, Thrive.

During the sold-out event, sponsored by the Commonwealth Club of San Francisco, Sandberg and Huffington offered insights into what it means to be successful, and why people need to spend more time relaxing.

Huffington said that society places too much emphasis on wealth and power as defining characteristics of success, and that this is literally killing us.

"We can never shrink ourselves down to our to-do list," she said.

Throughout the discussion, moderated by Sandberg, the one point the two kept coming back to was the importance of getting enough sleep. In between jokes about "sleeping your way to the top," the pair continually emphasized the hazards of being overworked and exhausted.

"For many years the way I thought that I would get everything done was to get less sleep," Sandberg said. The Facebook COO said she has taken Huffington's advice to heart; she now makes a conscious effort to not only sleep more, but to spend at least five minutes a day meditating, even though "it's really hard."

The importance of gender equality in the workplace was also a big topic. "We know that if you are better at working with half the population, whether you're most junior level employee or the most senior level CEO, you're more effective at work," said Sandberg.

"We can't afford not to change workplace culture," Huffington agreed. She declared that instead of The Art of War, CEO's would be better served by reading The Giving Tree.

Not all in the audience were entirely convinced. During the audience Q&A, one woman asked if the pair would hold the positions of power and influence they do now if they had taken their own advice at an earlier stage of their careers.

"When I look back, all my biggest mistakes were when I was burned out," Huffington replied. "I look back and life would have been incredibly easier" — if she'd slept more.

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