Half of executives responding to a recent survey said they check into the office several times a day when they’re on vacation, and two-thirds have entirely canceled or postponed vacation plans because of work demands.

The results come from a survey of more than 400 executives conducted by global leadership recruiting firm Korn Ferry. In addition to finding that 67 percent of executives changed vacation plans in the past year because of work demands, survey also results reveal that 57 percent do not expect to use all of their available vacation days looking ahead.

“Today’s executives are under constant pressure to drive growth, hit deadlines and deliver on the expectations of various stakeholders,” said Kevin Cashman, senior partner at Korn Ferry, in a statement. “The irony is that individuals who take time off are shown to be more productive, have higher morale, and are less likely to make critical mistakes.”

While 83 percent of executives will take some vacation days this year, according to the survey, they aren’t likely to unplug from the office. Only 5 percent said they never connect to work while on vacation. The chart below indicates remaining answers.

05252015 Korn Ferry Vacation Survey

What about those executives that don’t take vacation or alter their plans?

Executives overwhelmingly noted concerns about having “too much work to do” and an “increased workload upon their return” as the primary concern in stepping away from the office on vacation, when asked, “What worries you most about leaving the office for personal time/vacation?”

05252015 Korn Ferry Vacation Survey2

Source: Korn Ferry