This year Americans missed out on a record-breaking 658 million vacation days. Just to underline the point, that means that 658 million times the nation's bosses collectively said, 'Go for it! Kick back and relax -- we'll pay you anyway,' and 658 million times some U.S. worker, replied, 'No thanks, I'd rather just come in to the office instead." 

What could we possibly be thinking?

Sometimes, no doubt, vacation-averse Americans have correctly read their supervisor's not-so-subtle hints that while officially it's OK to take time off, really it isn't. But plenty of us do this to ourselves. We imagine that while we're off soaking up the sun or spending time with loved ones, our competitors will be working away furiously. Vacation, we fear, will make us lose our edge.

But science has a very clear reply to that worry: Get over it! As a well-timed post on the blog Science of Us points out, studies actually show that taking a break is actually likely to help you get ahead at work.

Less burnout, more money

The first bit of research outlined by writer Drake Baer draws a clear line between lack of adequate time off and professional burnout. "A small 2003 study took two groups of employees in the same company, one that took vacation and one that didn't. After coming back from vacation, the vacationers had the same level of stress as the non-vacationers, but much less burnout," he reports.

That's hardly shocking, but you might be more surprised to learn exactly how that difference in burnout levels seems to affect people's careers. Over time, not taking your vacation time seems to be correlated with making less money.

"A recent study of 5,641 adult Americans--released by the U.S. Travel Association and Project: Time Off, a 'coalition' of travel-industry companies and state/city tourism groups, so take that for what you will--found that people who took less than ten vacation days a year had a 34.6 percent chance of getting a raise or bonus in a three-year period, while people who took more than ten days had a 65.4 percent chance of landing a raise or bonus," Baer continues, noting that "while you can't say that vacation is the exact mechanism, that's quite the association: an 89-percent increase."

In short, science suggests that rather than giving you a professional edge, overwork tends to lead to burnout, poorer performance, and less advancement in your career. If you're curious about the exact mechanism by which vacations seem to increase performance, check out the rest of Baer's post for an interesting explanation of the likely psychology behind this correlation.

Or if you'd like to read more about the science of vacations, here's research on how to plan your getaway for maximum happiness, a psychological brain hack that can help you mentally switch off while you're away, and a study claiming to have determined the ideal vacation length.

How many unused vacation days have you racked up?