Constantly checking your inbox distracts you from your work, and leaves you in a “high alert” state of stress, according to researchers at the University of California, Irvine, and the U.S. Army.

To see how much stress email causes, researchers asked a group of people to take a five-day break from email at work. During this time, researchers monitored the heart rates of the participants, as well as the number of times they switched between windows on their computer.