All work and no play makes Jack a dull boy.

That's a lesson that more Americans ought to take to heart. In a couple of months, about 53% of U.S. workers will exit the year with unused vacation days, and 33% say they generally don't use more than half the paid vacation they are allotted, according to the 2019 Priceline Work-Life Balance Report.

As for what's causing this unhealthy pattern, well, a big piece of it is that our employers are getting into our heads. Among the survey respondents, 18% said they leave vacation on the table because they feel guilty about taking time off. The same percentage said they were just too busy to take vacations.

And it won't surprise anyone to learn that when people do manage to escape the office, that doesn't always mean they're getting away from the work: 29% said their companies or supervisors expect them to be "available" while on break, while 38% said they "feel pressure to check email or voice mail while away." And 15% of those surveyed said that "they end up working during some portion of every vacation they take."

"The respondents in this study report feeling pressure to work while they're on break," said Priceline Chief People Officer said Liz Dente in a press release. "They shouldn't. Instead, their company should feel pressure to show employees that they're valued, by making it clear that 'out of office' means fully disconnected."

A person is making a paper airplane at work.

Not taking time off can lead to being less productive at work. Image source: Getty Images.

Guilt starts early

That instinct to give the proverbial 110% -- and not take the time off that they're owed -- is even stronger among newcomers to an employer. More than 60% of those surveyed said they would wait at least six months after starting a new job before taking a significant vacation, and 21% said they'd wait at least a year.

On the optimistic side, while people aren't taking their full allotment of vacation, at least most of then intend to. In the previous edition of this survey, 59% of respondents said they planned to use more vacation time in 2019. And in the current edition, 66% of those surveyed actually said they intend to use all of their vacation days this year.

This is a worker and company issue

In a 2010 Psychology Today article, psychology professor Susan Krauss Whitbourne of the University of Massachusetts noted that all Americans face some level of stress at work, though the types will vary. Yours might be related to your tasks, or it could be that you're underemployed, or unhappy in the job you hold.

"Chronic stress takes its toll in part on our body's ability to resist infection, maintain vital functions, and even ability to avoid injury," she said. "When you're stressed out and tired, you are more likely to become ill, your arteries take a beating, and you're more likely to have an accident. Your sleep will suffer, you won't digest your food as well, and even the genetic material in the cells of your body may start to become altered in a bad way."

In short, it's important to do things that relieve stress, and taking time off is an important part of that. To make that happen, companies and supervisors need to be supportive and encourage employees to use their vacation days. It's to employers' benefit too: Working too long without taking a vacation can lead to burnout, or cause people to fall into ruts where they're doing their jobs, but not doing them particularly well.

So the employer has both the responsibility and (if they recognize it) the motivation to set the right tone when it comes to time off. That means bosses should be proactive in scheduling vacations and minimizing the pressure on people to work during them. Doing so would make it easier for workers to take the full amount of time off they're owed and actually relax during those breaks. And that will give them a better chance of coming back recharged and ready to perform.