It’s Time to Start Planning a (Work-Free) Vacation. Here’s Why.

May 9, 2019, 5:30 PM UTC

Let’s face it, you need some time off. Not only are you leaving money on the table by not taking vacations (which are, after all, part of your compensation) but, as your already humongous to-do list keeps getting longer, it’s harder to come up with fresh ideas, or the energy to execute them. What’s more, if you yearn to get away and haven’t felt able to, you may be headed for a nasty case of clinical depression.

Next stop: Burnout City. And nobody wants to go there.

A strong link between nonstop work and depression turns up in a fascinating study, conducted by pollsters Ipsos Public Affairs for Allianz Global Assistance USA. Every spring since 2009, Allianz has surveyed 1,000 working adults and asked, first, whether they consider vacations important to their well-being and, second, whether they have definite plans to get away, or have done so in the preceding 12 months. People who rate the importance of vacations highly, but say they are unlikely to get one, are suffering what the researchers call a “vacation deficit.”

Here’s the twist: In the most recent survey, respondents also filled out a short questionnaire called a PHQ-9, which the medical profession uses to identify symptoms of clinical depression—including loss of interest or pleasure in daily life, feelings of failure or hopelessness, insomnia, loss of appetite, and trouble concentrating.

The correlation between “vacation deficit” and PHQ-9 scores is startling. Consider: About one in three (30%) of people reporting a “vacation deficit” showed signs of mild to moderate depression. It gets worse. An estimated 6% of the U.S. population suffers from severe clinical depression. Among non-vacationers, the percentage doubles to 12%. Among people who rated the importance of time off highly but said their last vacation was “more than two years ago,” over half (56%) showed sky-high PHQ-9 scores, indicating severe depression.

It’s pretty well-known by now that getting away from it all for a week or two is essential for both physical health and productivity, so why do we hesitate to do it? Research suggests it’s not usually bosses who stand in the way. (One study found that only 3% of managers discourage their direct reports from using their vacation time.) Coworkers, however, might be a different story. Two years ago, the Allianz survey asked people to describe how they felt about scheduling a breather. About 25% of Americans in every age group—and even more millennials (37%)—reported negative emotions, like nervousness and guilt.

“People felt especially guilty about leaving colleagues with extra work to do in their absence,” says Daniel Durazo, the Allianz director who has overseen these vacation studies for the past 10 years. “But whether coworkers who would be picking up the slack really will mind, or whether people just fear they will, we really don’t know.”

Bob Glazer, founder and CEO of marketing firm Acceleration Partners, has found a way to moot that question. “Vacations are a great chance for people to learn how to delegate and plan ahead,” he says. “We want to create a system where there is always someone else who can do your job if you’re not around, and you can do theirs. It’s become part of our culture.”

To build that bench strength, Glazer wants his employees not just to take off, but to stay offline, and completely out of touch with the office, while they’re gone. Although Acceleration Partners has an unlimited-vacation policy, “people just weren’t using it,” he says—or, if they did go away, they checked in to work electronically so often that they might just as well have stayed there.

So last year, Glazer started paying $750 to anyone who disappears on a real, relaxing getaway: No answering emails, for instance, or fielding phone calls, or sitting in on teleconferences. About half of his 150 staffers worldwide have taken him up on it. “In case of an emergency, people tell their colleagues how to reach them by text on a non-work phone,” Glazer says. “But so far, that’s never actually happened.”

One benefit of having someone else cover for you now and then: A fresh pair of eyes. Team members left to fend for themselves “get a chance to do something new, and they may even find a better way to do it,” notes Michelle Kalinowski, an Acceleration Partners senior account manager in Australia who has gone off on two 10-day jaunts in the past year. During one of them, someone filling in for her made a few changes that cut an hour from a routine task the team had been doing. “The new way is much quicker,” Kalinowski says. “It’s saved us a lot of time.”

Not every employer is prepared to pay people extra to get lost, of course. Still, Glazer, who says he gets his best ideas while traveling or sitting on a beach somewhere, believes companies would see a big jump in productivity (not to mention retention) if they gave employees the green light to have lives outside of work, including vacations that refresh and recharge them. “Culture is all about what you reward,” Glazer says. “If you reward nonstop work, that’s what you’ll get.” In the long run, it’s unlikely to be pretty.

Click here to read more stories from Fortune’s “Work It Out” series.