Learn how these successful entrepreneurs have all discovered, no matter how well you think things are going there’s always something gnawing away at your consciousness and keeping you awake at night.

You’ve survived the startup stage, secured your first round of funding and the growth forecasts are looking good, so you can sleep easy at night, right? Wrong. As these successful entrepreneurs have all discovered, no matter how well you think things are going there’s always something gnawing away at your consciousness and keeping you awake at night.

Having just completed a $2.6 million fund raising round, Arnar Olafsson, CEO of Icelandic travel startup Kaptio, is anxious about the next stage of business growth.

He says: “How fast we should grow is a question that I ask myself all the time. Should we do it with additional VC funding or focus on becoming profitable and take it from there? And if we decide on the latter, will we lose the first mover advantage in the market that we believe we have? How do we grow our implementation base whilst at the same time ensuring our current customers are happy? To that end, when do we start to invest in PR and marketing; now in order to generate demand and brand awareness or later? The decisions we make now will dictate how well we scale, and knowing that is pressure enough to keep you awake at night.”

For Daniel Döderlein, CEO of Norwegian mobile payments startup Auka, the night-time worries are all about innovation. “When I wake up with new ideas I’ve learned to write them down immediately in case they’ve disappeared by morning,” he says. “I am plagued by the fear that my brain will one day stop thinking of solutions to make people’s lives easier. Not having enough time in the day to attack all challenges or fully try out all new ideas is frustrating.”

You might think that younger entrepreneurs are more resilient to the stresses of starting up and find it easier to switch off at night. But as Jordan Daykin, the 21-year-old founder of GripIt Fixings, has realised, once you start hiring staff, the responsibility can weigh heavily on your mind.

Daykin, who launched his business from his garden shed at the age of 18, now leads a team of 29, which is growing all the timeHe says: “They are very talented people, some older than me, and some younger. I’ve earned their respect and trust, but I’m very aware that their career progression is in my hands. They have bought into the business and the growth strategy that I’ve employed, which I find quite overwhelming sometimes and which does keep me awake at night.”

People worries are partly to blame for Neil Costigan’s sleepless nights. The CEO of Swedish behavioural biometrics firm Behaviosec says his biggest ‘stress’ is the age-old dilemma of juggling growth versus people versus company culture. “I worry about retaining the David versus Goliath, 24/7 startup culture as you add people – you don’t want to slow down innovation, and you want to keep the place as desirable and exciting to work in as possible,” he says. “The jump from 15 people to 25 people is where it all changes, and is a worry.  That, plus the fact that we are in the far north of Sweden; the damn light also keeps me awake these days.”

Michael Whitehead, CEO and founder of New Zealand-based automated data warehousing firm WhereScape worries about cash, competition, and his spelling prowess. “Accountants look at the finance systems, I worry about cash,” he says. “Don’t tell me it’s like judging how well off I am by how much cash is in my wallet. Cash in the bank is everything. The New Zealand Government sent me on an entrepreneurship course at MIT, and the guy that ran it, Ken Morse, had something he wrote up on the board, CFISMITYM – Cash Flow Is More Important Than Your Mother. And he was right.”

Competition is another sleep deterrent. “But it’s not the big competitors, or even any other company; I don’t care what they can do, they can come at us from all sides,” he says. “Competition is about us. How competitive are we? Can we move quickly enough? It is never about the good ideas, it’s about the good ideas that we can’t do because we don’t have the resources.”

And the spelling thing? “Spelling the word entrepreneur was a big problem when I was a category winner in the New Zealand Entrepreneur of the Year Awards. Had to keeping writing the damn word all the time. Couldn’t get it out of my head.”

It seems that entrepreneurs are destined to be eternal insomniacs, and Fran Brosan, founder and chair of digital agency Omobono, is inclined to agree. She says: “In the first years of business you move forward in an irregular tempo; slow sections mix with frenetic intermezzos.  It’s only later, once the business is up and running that it gains its own steady beat. When you are driving the beat forward yourself, you don’t have time to worry about whether it will work or not.

“But once you stop being the de facto drummer, you worry about it suddenly stopping mid bar. So what keeps you up at night?  Mouths to feed. This time not your own or your family’s, but other people’s.  Quite simply, the business is bigger, you employ more people, you have hired a team to deliver.  But as an entrepreneur I don’t think you ever stop feeling responsible for bringing home the bacon.”

Read article on Forbes site.