Can anyone remember a time before e-mail? A time before inbox notifications, color-coded message labels, and "Mark as unread?" The practice of using written letters to do business is long gone, replaced by instant digital communication and its byproduct: stress.

It turns out many successful business titans consistently practice a special kind of mindfulness when it comes to email in order to stay sane and keep their companies afloat. They notice how inbox stress affects their responses, how it affects how they are perceived, and how it makes them feel. Doing so helps them do something very key: slow down.

Randi Zuckerberg, founder of Zuckerberg Media and editor-in-chief of Dot Complicated, exercises two rules when it comes to email. She not only refuses to rush to check her inbox after she wakes up in the morning -- choosing instead to wait at least 20 minutes -- but she also recognizes when her emotions affect her email replies: "If you find yourself writing an email that is overly emotional, whatever you do, don't send it right away. Stick it in your drafts folder and come back to it later. You'll likely breathe a sigh of relief that you didn't send it once you've read it again!"

Meanwhile, Jonathan M. Tisch, executive of Loews, is able to take a pause when he notices how the words in his email responses affect others. In speaking with Adam Bryant of the New York Times, he asserts: "Never start a paragraph with the word I, because that immediately sends a message that you are more important than the person that you're communicating with." For at least 35 years, Tisch has recognized that "When you start to train your thinking about how to not use I, you become a better writer, and it teaches you how to really think through an issue."

As we become constantly available to answer email, we allow ourselves to become constantly available for work, even hours after our typical 9-5 shift has ended. However, remember this message: we can mitigate the effects of email stress when we notice its effect on us, and refuse to rush.