Two-fifths (38 per cent) of U.S. employees say they haven’t taken a vacation in the past 12 months, according to a new survey by Eagle Hill Consulting.

The survey, which polled more than 1,300 workers, found lower-income employees (59 per cent), generation Z (46 per cent) and workers without a college degree (46 per cent) were most likely to have skipped vacation.

Nearly half (46 per cent) of workers said cost is the No. 1 impediment to taking time off, followed by self-imposed pressure to stay on top of work (30 per cent), a heavy workload (27 per cent), a lack of availability among colleagues to cover their work (26 per cent) and a lack of paid time off (25 per cent).

Read: Survey finds unlimited vacation a top driver of employee belonging, engagement

While more than half (56 per cent) of employees said they fully disconnect from work during vacation, a quarter (25 per cent) said they still check work emails and messages. Nearly half (45 per cent) of workers said they’re feeling burnt out at work, a percentage that increased among employees aged 18 to 34 (52 per cent) and women (48 per cent).

“It’s not just employees who benefit from taking time away from work,” said Melissa Jezior, president and chief executive officer of Eagle Hill Consulting, in a press release. “When employees have space away from their job, they often return more energized and focused. Ultimately, that benefits their employer and customers.”

Read: Survey finds 50% of employees can’t completely disconnect from work while on vacation