Shopify CEO and cofounder Tobias Lütke has one word to describe the responsibility of being a chief executive: “crushing.”

During the company’s early years, Lütke was so stressed about having enough money to meet payroll and worried about losing the money family members had invested into the company that he often struggled to sleep at night, he said on an episode of NPR’s “How I Built This with Guy Raz” in August.

“One thing I found about the entrepreneur journey, or at least mine, is that you basically exist in two different states,” Lütke, who launched Shopify with his cofounders in 2006, told NPR. “There’s the state of ’things are coming together, and I think if we do this we’re unbeatable.’ And [there’s] the state of complete dread and ‘we’re dead, we’re dead, we’re dead tonight.'”

To deal with it, Lütke intentionally prevented the e-commerce platform from growing as quickly as it could have between 2009 and 2010, he told NPR.

"If you come from [an] engineering [background], you know that something's always a bottleneck, and then the moment you remove that, something else becomes a bottleneck - and the same goes for companies," Lütke told NPR. "At this point, I intentionally slowed down the growth of the company a little bit just because I needed it to be manageable for me."

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Lütke says he also wrote computer programs - a longtime hobby of his - and confided in his wife, Fiona, to relieve his stress.

Many successful CEOs rely on a hobby to help relieve the stress of running a business, as Business Insider has previously reported. Former Microsoft CEO Bill Gates likes to read before bed, while Berkshire Hathaway CEO Warren Buffett plays the ukulele. Twitter cofounder and CEO Jack Dorsey runs six miles a day and sets aside a specific day to tackle each part of his massive business.

"The bottoms are deep, and the implications of what failure means - it just means so much," Lütke told NPR. "It can change everyone's life story to a significant degree."

For Lütke, Shopify's success has already paid off: Forbes puts his current net worth at $2.7 billion.