February 5, 2016 5 min read

Opinions expressed by Entrepreneur contributors are their own.

I work a lot. I really enjoy what I'm doing, so I work insane hours. But something I don't always correlate in my mind. Is this 12+ hours a day working is really effective.

We all realize when starting a new venture you're more or less expected to work insane amount hours beyond normal expectations. Some believe it’s a badge of honor that can determine the fate of your business. Take Elon Musk. He’s proudly exclaimed:

“Work like hell. I mean you just have to put in 80 to 100 hour weeks every week. [This] improves the odds of success. If other people are putting in 40 hour work weeks and you’re putting in 100 hour work weeks, then even if you’re doing the same thing you know that….you will achieve in four months what it takes them a year to achieve.”

Musk isn’t just sitting at his desk the entire time -- he does a lot of traveling -- but still, that’s not good advice for every entrepreneur out there. Research back to the 19th Century has discovered that businesses that have embraced the 40-hour work week were more productive and profitable. For many individuals, working more than eight hours per day can be damaging to a person’s health. Studies have also found “that doing more than 11 hours of work a day raised heart disease risks by 67 percent.”

Despite these findings, we insist on putting in lengthy workdays because we’re passionate about our businesses, have deadlines to meet or it’s just the corporate culture nowadays. I'm guilty of this, as are many of you reading this. The problem with this mentality, is that working more than 12 hours a day is actually killing your business.

Creates health problems.

Working excessively long days is harmful for your health. Numerous productivity studies have found that overworking leads to sleep deprivation, depression, impaired memory, drinking problems and health concerns including diabetes and heart disease.

This can impact your business because you and your employees become more likely to call in sick or have a high employee turnover - which can harm the bottom line since paid sick days have cost employers $160 billion annually on top of the increasing cost of health insurance. Other studies have found that these health concerns cost businesses $300 billion thanks to lowered productivity, absenteeism, and actual health-care costs.

Related: 7 Reasons Too Much Coffee Is Killing Your Career

Decreases productivity and innovation.

Longer workdays won’t make your business more productive. The Organization for Economic Cooperation and Development actually found that while workers in Greece averaged 42 hours at work every week in 2014 (2,042 hours annually), employees in Germany not only clocked in 1,371 total hours in a year, or around a 28 hours per week, they were also 70 percent more productive. Even more interesting is a study showing that, managers couldn’t tell the difference between the employees who had worked 80 hours per week and those who pretended to.

Besides decreasing production, working too much can decrease creativity and innovation. NPR has a great example to illustrate this point from author Jonah Lehrer:

“If you're an engineer working on a problem and you're stumped by your technical problem, chugging caffeine at your desk and chaining yourself to your computer, you're going to be really frustrated. You're going to waste lots of time. You may look productive, but you're actually wasting time.”

Leading becomes more challenging.

In Ron Friedman's article “Working Too Hard Makes Leading More Difficult,” Friedman states, “It is surprisingly hard to recognize the damage working excessive hours inflicts both on leaders and their teams.” Friedman's research led him to conclude that overworked leaders make poor decisions and impaired judgments, as well as have difficulty keeping their emotions in check.

Even more detrimental is the fact that the entire leadership team and organization will follow suit and take on these ineffective traits as well.

Related: Working Long Hours Could Kill You

Profit, revenue and customer satisfaction won’t improve.

According to Delta Emerson, president of global shared services for the tax services firm Ryan, "Since we implemented flexible workweeks in 2008, all the metrics a CEO cares about have gone in the right direction.”

Emerson adds that the company has reduced turnover and doubled revenue and profits, as well as reaching all-time client satisfaction scores.

Not cost effective.

Working 12 hours a day isn’t cost effective for your business. For starters, you’re using more electricity and office supplies by being in the office so much but the real cost is what happens to your employees. Instead of pressuring your team to work 12 or more hours per day, implement a flexible schedule. Not only will you save money on electricity, supplies and probably office food, you’ll cut costs because everyone will be more productive, you’ll have a lower turnover rate, you’ll attract a wider talent pool, decrease sick days and help your business grow faster.

Related: 7 Physical and Mental Detox Strategies You Should Start Today