Summer often makes us nostalgic for our childhood vacations: long, carefree days spent by the beach, in the woods, or with friends and family.

However, as adults, those memories can seem all too far away.

If you’re American, you probably take drastically less vacation that workers elsewhere. First, most U.S. employers only offer 10 paid vacation days, versus the 28 in the UK and 30 in France. The US is the only advanced economy that does not guarantee vacation to its employees, and according to a report by the Center for Economic and Policy Research, 1 in 4 Americans receives no paid vacation at all. What’s more, of those Americans who actually do take time off, most actually end up working on their vacation. The prevalence of smartphones and wifi makes it even harder to disconnect.

But the problem isn’t limited to the US. An Ipsos/Reuters survey across a number of countries shows that only two-thirds of employees actually use all of their vacation days. And wherever you are based, if you’re someone who is running your own company, working independently, or billing by the hour, time off can mean losing clients or forgoing earnings. The growing trend toward “free agent” work lives, where people are independent contractors with fewer ties to organizations, leaves a growing percentage of the workforce without vacation benefits at all.

But even salaried employees at stable companies with paid vacation time might legitimately feel like they can’t leave the office for an extended period. Monica Worline, Affiliate faculty at the Center for Positive Organizations, University of Michigan, explains that this phenomenon “reflects the pressure to be at work and be productive.” The most common reason given in these circumstances is the possible repercussions of taking time off. What if they are replaced? Seen as irresponsible? What if their colleagues and competitors outperform them or somehow take over? What if major problems happen while they are away? What if their bosses question their commitment? (When Steve Jobs found out that one of his employees had taken up golf, he exclaimed “Golf? Who has time for golf?” Along with vacation, a hard-driving boss may even see hobbies and recreation as nothing more than time you are wasting instead of being productive.)

As for employers, they appreciate that their employees check in while on vacation and are only an email away. After all, their employees’ continued presence even while on holiday will ensure that nothing falls through the cracks and that there will always be a go-to person. Research shows that managers tend to judge employee commitment to the organization by their levels of “citizenship behaviors,” which sometimes includes going above and beyond their job tasks to serve the common good. If managers confuse not taking vacation with citizenship, or are not supportive of taking vacations, then employees will leave much more vacation time on the table regardless of the overall organizational policies.

Unfortunately, the logic of both employees and employers is highly flawed. Both fail to realize that cutting into vacation time is actually detrimental to both organizations and their employees both in terms of financial and productivity costs. But while I wish it were different, I recognize that if you don’t get much vacation time, can’t afford to take any time off, or work for a boss who scowls at the idea of a two-week vacation—or even a single full week off—you will have to figure out a workaround.

It’s vital that you do so. Research by Sabine Sonnentag suggests that detaching from work is essential to enhanced productivity. Her work has shown that, while people who do not detach from work suffering from greater levels of exhaustion, those who do recover from job stress and are more likely to have higher engagement levels at work. “A high level of recovery and work engagement seem to reinforce each other,” as she explained to me in an interview.

As Worline explained to me, “We all need to unplug now and then! In fact, we come back better able to perform when we allow adequate breaks, and there’s a good deal of evidence that shows this across very different kinds of industries.” This is true especially when work demands are high – which is also when professionals might be least likely to give themselves a break. “Research on what it takes to thrive at work shows that high intensity jobs that require a lot of thinking and learning hit a tipping point at which we can no longer perform unless we allow for periods of recovery that build up our vitality.” How can HR professionals make sure that personnel will actually detach from work? Worline, who also collaborates with our center at Stanford, the Center for Compassion and Altruism Research and Education, suggests that “Human resource professionals can educate people within the organization about the value of breaks, and can look at accrued vacation time as a red flag for burnout.”