By Elizabeth Bernstein

One evening, after a frustrating chat with his boss, Jason Bauman sent an email to a co-worker. He wrote that his supervisor never praised him, only criticized, and said he found this frustrating.

He went on for several hundred words. Mr. Bauman, the manager of a cellphone store at the time, complained that his boss was bad at his job. He said the man was jealous because he made less money than his employees. He insisted his boss had no right to give him what he called “a hard time.”

“It felt really good writing the email and hitting send,” says Mr. Bauman, a 30-year-old who lives in Souderton, Pa.

Not for long. Mr. Bauman says he regretted his angry email shortly after he sent it. “It kept me focusing on the issue much longer than I should have, mulling it over and over all evening,” he says. He felt worse the next day, when he learned his co-worker had forwarded the email to his boss.

The research has been clear for decades: Venting is bad for us.

And yet we do it—more now than ever thanks to the ease of the Internet.

The “e-vent”—expressing anger via email, text or chat, or on social media sites such as Facebook or Twitter—can be hard to resist. It’s speedy: We can share our frustration with a friend, or the world, almost immediately. It’s handy: We can e-vent from anywhere as long as we have our phone. And it feels safe: We’re behind a screen.

In studies, people report that they feel better after venting. But researchers find they actually become angrier and more aggressive. People who vent anonymously may become the angriest and most aggressive.

“Just because something makes you feel better doesn’t mean it’s healthy,” says Brad Bushman, a professor of communication and psychology at The Ohio State University in Columbus.

A bad vent can come back to hurt you. You could alienate friends or family, or get pegged as a whiner or someone with anger-management issues. And because what happens on the Internet stays on the Internet—forever—you could do lasting damage to your reputation.

Venting has an ancient history. Aristotle believed in catharsis—the purging of emotions. More recently, Sigmund Freud talked about the hydraulic model, saying that if someone holds anger inside without letting it out, it will build to dangerous levels, much the way steam in a pressure cooker will build if it is not vented. Dr. Bushman says most people still believe this to be true, even though there is no scientific research to support it.

We all vented before the Internet, of course. But it wasn’t so immediate. We had to pick up the phone and call someone, or wait for our spouse to come home from work. This gave us time to cool down and maybe even have a relaxing cocktail. And venting in person, or even over the phone, allowed us to get immediate feedback and gauge when we were going overboard.

Dr. Bushman has conducted multiple studies that show that venting anger or frustration isn’t beneficial. In one study, published in 2002, he asked 600 college students to write an essay on abortion. He matched each student with a “partner”—in reality a researcher—who purported to have the opposite view and rated the student’s essay negatively on organization, writing style and originality.

Dr. Bushman then divided the students into three groups: The “rumination” group was instructed to hit a punching bag while thinking about the person who graded their essay. The “distraction” group was told to hit the punching bag while thinking about becoming physically fit. And the control group did nothing. Then each student reported his or her mood, choosing from angry adjectives such as “mean,” “hostile” and “irritated” and feel-good adjectives such as “calm,” “happy” and “relaxed.”

The students in the rumination group were the most angry and most aggressive, while those in the control group, who did nothing to vent, were the least angry or aggressive, the study found.

E-venting is particularly risky, experts say. We think it’s private because we can do it in a secluded place, like our bed while we’re in our pajamas. We have our phones with us all the time so we often e-vent before we’ve had a chance to calm down. A rant put out via the Internet is a click away from being shared. And shared. And shared.

We typically sound angrier in print. And when we write down something, we can reread it, over and over, and stew.

With e-venting you don’t get immediate feedback from your listener, so you might not know when to stop. “You can’t see the eye rolling,” Dr. Bushman says.

I can relate. Last Christmas, stuck in the JetBlue terminal at the airport waiting for a delayed flight, I became increasingly annoyed at the airline’s choice of holiday music: Alvin and the Chipmunks.

I tweeted JetBlue and demanded that they halt the Chipmunk squeaking. They said their customers chose the music. I replied: “I find that hard to believe.” They tweeted me a heart. It took me five more tweets before I felt ridiculous for complaining publicly about small rodents singing. I turned off my phone.

If venting just makes us madder and meaner, what should we do instead? Dr. Bushman recommends addressing both the physiological and cognitive components of our anger.

To calm our body down, we should delay our response, counting to 10 or, as Thomas Jefferson is said to have suggested, 100. Dr. Bushman also recommends trying to relax by taking deep breaths or listening to calming music.

Turn off your computer or phone until your anger has subsided. You might even consider blocking a person’s phone number temporarily, so that you won’t be tempted to text or email.

To quiet your mind, Dr. Bushman suggests distractions such as reading a nonviolent book, working on a crossword puzzle, taking a walk.

Do something that is incompatible with anger or aggression: Kiss your sweetheart, help someone in need, pet a puppy.

Try to distance yourself from the incident that upset you. Observe the situation as if you are an outsider.

Eat something healthy. “People who are hungry are cranky,” Dr. Bushman says.

Mr. Bauman says he learned a lesson about e-venting when his co-worker shared his email with his boss: “It was very easy for him to hit forward,” he says. Now, if he wants to talk about something frustrating, Mr. Bauman chooses one of several close friends and vents in person. He left the cellphone company shortly after his email incident, though there weren’t any ramifications from it, and now works as a writer and editor for an Internet marketing firm.

He also writes letters to people who have annoyed him, but saves them in a file on his computer instead of sending.

“It helps me work through whatever is frustrating me,” he says. “Sometimes you just need to air it out.”