Despite the health benefits of taking vacations, many employees aren't, but why?

People who take more vacations have better quality of life, WebMD explained. Individuals who take vacations have lower stress levels, reduced risk of heart disease, increased motivation and a better overall outlook in life. It isn't necessary to take two weeks off to feel the effects either – employees can reap the benefits from even 24 hours off from work. The happiness boost comes even before the vacation starts. Planning alone is enough to improve one's mood. 

But Americans aren't taking vacations these days. Four in ten employees in the U.S. provided with vacation time don't take advantage of it, according to an Oxford Economics study. The U.S. is one of only a few industrialized nations that doesn't mandate paid time off, but many employers still offer it as part of benefits packages. However, most people offered paid vacation days don't take advantage – on average they used only 84 percent of their allotted time off, leaving an average of 3.2 days unused. 

In fact, last year Americans took the least amount of vacation in nearly four decades, Reuters reported. In 2013 alone, employees used an average of 16 out of 20.9 available vacation days. Between 1976 and 2000, individuals used an average of 20.3 paid days off. The 169 million days of U.S. vacation time forfeited by employees is equivalent to $52.4 billion in lost benefits. By working instead of taking paid time off people are basically working for free. 

The drop in vacation time coincided with the financial crisis between 2007 and 2009, the news outlet reported. A 2010 survey by Reuters and Ipsos found that a mere 57 percent of Americans used their vacation time. 

Wealthy workers are the ones that tend to earn more vacation time – they are also the individuals who have a habit of leaving paid days off unused most often. People with a yearly income of $150,000 left an average of 6.5 vacation days unused last year. Those who earn less than $29,000 annually didn't take advantage of 3.7 paid vacation days on average. 

Promoting vacation days at your own small business
Small business owners can do a number of things in order to promote using vacation time among their employees, Entrepreneur explained. For example, take your own vacations. By taking time off – responsibility – and keeping employees in the loop while you're gone, you're setting an example as someone who enjoys the benefits of rest. As long as you keep your staff updated, they will know what to do in your absence, and hopefully follow in your example in terms of taking time off.

In addition, give long vacations during the holiday season, the publication suggested. What's the point in having everyone hanging around the office if there's no business to take care off. Everyone else is probably enjoying their own vacations. Your staff will be thankful for the extra time they get to spend with their families, and will come back refreshed and ready to work. 

Just make sure not to overextend your promise of vacation days, Entrepreneur noted. Small businesses don't have budgets as large as massive corporations, so be smart when allotting vacation. If you're worried about the burdens of offering too much time off, consult a financial services expert in order to determine how to offer vacation days in the most cost-efficient way possible. 

"America's work martyrs aren't more successful. We need to change our thinking. All work and no play is not going to get you ahead – it's only going to get you more stress," said Roger Dow, president and CEO of the U.S. Travel Association, according to Reuters.