An increasing number of Americans are opting out of vacations. An online survey of 1500 adults, conducted by the travel website Skift, revealed that 42 percent of Americans took no vacation days in 2014.

Financial concerns may play a significant role in this decision: only 13 percent of respondents said they could afford to take all 10 vacation days typically allotted to full-time employees. (For those without the benefit of paid vacation days, taking time off could be even more of a financial strain.)

However, vacation time has serious mental and physical health benefits (and there’s no reason that vacations need to be extravagant, or even involve travel, to afford these benefits).

Vacations are often referred to as a time to “recharge”—and increasingly, a time to “unplug,” as our dependence on smart phones and an “always on” expectation from employers impedes our ability to enjoy the time when we’re not physically in the office. Stepping away from work responsibilities and spending time with friends and family can help counteract the adverse health affects of workplace stress.

1. Physical health

The potential health benefits of taking vacations include decreased risk of heart attack and coronary heart disease. According to a University of Massachusetts Amherst study from 2000, middle aged men at high risk for coronary heart disease who vacationed annually had a lower risk of mortality. Vacation and other forms of leisure activities that rejuvenate the mind and body can help lower stress hormones and even lead to smaller waists.

2. Mental health

Vacations can offer significant psychological benefits: A 2005 study published in the Wisconsin Medical Journal looked rural women in central Wisconsin with fascinating results. "[W]omen who take vacations frequently are less likely to become tense, depressed, or tired, and are more satisfied with their marriage," the study reported. "These personal psychological benefits that lead to increased quality of life may also lead to improved work performance." Vacations and leisure activities have been shown to ease job stress, as well as strengthen family bonds and other social relationships.

A study published in the Journal of Happiness Studies in 2013 noted in its abstract, "Engagement in passive activities, savoring, pleasure derived from activities, relaxation, control, and sleep showed strong relations with improved health and well-being during and to a lesser degree after vacation."

3. Life satisfaction

The extent to which the positive effects of vacation last beyond the duration of the time away is still being debated, but several studies have demonstrated some degree of lingering effects (an important reason why employers are, or should be, encouraging their employees to actually use their vacation time). A study of employees at the University of Tennessee suggested that improved life satisfaction resulting from vacations remains even after employees return to work. A study published in the journal Applied Research in Quality of Life in 2010 evaluated 1,530 Dutch adults, and found that those actively planning vacations reported increased well-being. Among those whose vacations were "very relaxing," the effects of the vacation lasted up to eight weeks after the vacation.

4. Productivity and creativity

Vacations have been shown to decrease employee burnout and improve productivity. An Ernst & Young internal study in 2006 revealed that employees who took vacations often were more likely to remain at the firm, and that taking vacations actually improved employee's year-end performance evaluations.

Daniel J. Levitin, the director of the Laboratory for Music, Cognition and Expertise at McGill University, wrote in a 2014 op-ed in the New York Times that vacations can give the processing centers of our minds a much-needed break. "If we can train ourselves to take regular vacations—true vacations without work—and to set aside time for naps and contemplation," writes Levitin, "we will be in a more powerful position to start solving some of the world’s big problems."

5. Bottom lines

Stress adversely affects businesses’ bottom lines by inducing burnout, decreasing productivity, and contributing to poor physical and mental health. Workplace stress has been blamed for up to $190 billion a year in healthcare costs in the United States. While vacations aren't a magic solution for erasing workplace stress, it might be time to shift our cultural attitude about vacation and make taking time off a priority rather than something that just doesn’t fit on the calendar.