Workplace experts say such job creep has become a prime contributor to burnout—a phenomenon getting renewed attention since the World Health Organization included a more detailed description of it in the most recent edition of the International Classification of Diseases in May. Though the WHO stops short of calling burnout a medical condition, it describes it as a syndrome brought on by “chronic workplace stress that has not been successfully managed.”

The proliferation of smartphones and workplace communication apps has created unrealistic expectations of how easily—and often—workers should be able to switch from personal to professional tasks, researchers say.

In an April survey by Chicago-area mental-health center Yellowbrick, 62% of 2,059 working adults between the ages 23 and 38 said they felt pressure to be available around the clock through email, Slack and other work-communication channels. A recent study by researchers at Virginia Tech, Lehigh University and Colorado State University found that even the expectation of checking work emails on weekends and after-hours triggered anxiety and other harmful health effects among workers.