Can't stop: Most Americans work on vacation

A majority of workers check in with their office when they're on vacation, a new study from job placement agency Accountemps shows.

Roughly 56 percent of workers surveyed this year said they touch base with work when they're supposed to be taking a vacation break -- up from 41 percent of workers in 2016. The survey included more than 2,800 workers from 28 U.S. markets.

Who are most likely to be checking their emails or answering calls instead of relaxing and enjoying their break?

"Millennials -- without question, and one of the main reasons for that is the use of their smartphones," Accountemps Regional Vice President Richard Deosingh told CBS News in an interview.

The survey found baby boomers were the most likely to turn off their phones and unplug from work. The study also found that employees plan to take only nine vacation days this summer, down from 10 last year.

How can you be confident before you take your vacation that you'll be able to unplug? The key is planning ahead. 

"Make sure you have a colleague or colleagues available to cover for you while you're out," said Deosingh, "and make sure you arm them with enough information as possible so they can make decisions on your behalf."