A 2012 study from the University of California, Irvine found that people who were unable to access email for five days were not only more productive, they had “more natural, variable heart rates.” Over at the Atlantic today, Gloria Mark, a professor of informatics at the University of California, Irvine, said people check their email on average about 77 times per day, and it’s the checking of email (rather than writing) that is most stressful.

View the full story on the Time website.