(LifeWire) -- What do you do when someone unloads their personal dirt on you? Shauna Moerke says she knows a lot about that. The human resources specialist in Eagan, Minnesota, says she'll never forget the time she was making small talk with a former co-worker who then suddenly dropped a bombshell.
"She confessed to me that as a teenager she was raped by her father, got pregnant, had the child, who ended up having developmental problems, and because of the child still had to have contact with her father," says Moerke, 27.
"I don't know what made her tell me."
Whatever the reason, Moerke says, she seems to be a magnet for people who have secrets to share.
"I guess I just come across as very empathetic, but sometimes the personal stuff gets to be a little much."
That's just the thing, say experts: Listening to people vent can sometimes carry a price. How do you respond? Should you always keep their secrets? And when is it OK to intervene -- or even alert the authorities?
Lesley Withers, an associate professor at Central Michigan University who studies nonverbal, interpersonal and emotional communication, says sharing can be cathartic for the confessor but burdensome, even dangerous, for the listener.
"There's a term for those who repeatedly dump their problems on those around them: social allergens," she says. "A little exposure is unpleasant, but repeated exposure over time can, quite literally, make us sick. The stress of being around such a person, or even the dread of anticipating an encounter with that person, can affect our physical and emotional health."
Confessions at 30,000 feet
But confessions don't always have to be toxic, says Tina Tessina, Ph.D., a Long Beach, California-based psychotherapist. In fact, you may be doing the person a favor by listening. "If people confess to you, it means they trust you, look up to you, and believe you can be helpful to them, so it's a compliment" -- even if they're strangers.
Allan Bacon, 42, an author and blogger in Charlotte, North Carolina, travels frequently for business, and as a result meets all kinds of people on airplanes -- many of them who seem eager to vent once they're miles above solid ground.
"I think it's partly because we are strangers and partly because you are in this relaxed atmosphere where you are truly stuck for several hours," Bacon says.
Recently, on a flight in Europe, a woman seated across the aisle from Bacon leaned over and said, "I've never told anyone this before, but my husband and I are having trouble getting pregnant."
"It was clear that she was a little uncomfortable that she had just shared that, but I just acknowledged how difficult that is, having known lots of people who have gone through it," he says. "After that uncomfortable moment for her, she relaxed and we continued talking about our lives. At end of the trip, she gave me her business card and offered to stay in touch."
When a secret is illegal
Jane Straus, a life coach in Mill Valley, California, has heard clients complain about all kinds of worrisome topics. One of the biggest, she says, is harboring someone else's secret.
For example, when one of Straus' clients learned that her friend and business associate had started growing marijuana to sell, she told Straus she didn't know what to do. The client "felt very uncomfortable learning about this, particularly because they had co-founded a nonprofit that would be jeopardized if this illegal activity ever came to light."
In situations like these, Straus says, it's best to speak up. "If you do hear a secret that puts you in a moral quandary, let that person know as soon as possible," she says. "Tell them that you feel burdened by the secret and that you're troubled by their behavior. If you need to distance yourself because their secret has hit a 'moral nerve,' let them know.
"If someone is doing something that is harmful to another -- for example, molesting a child -- this is the time to give an ultimatum: 'If you don't report yourself, I will report you.' Follow through. No promise of keeping a secret counts as much as protecting children or those who have been harmed."
Thinking about spilling the beans to someone? Tessina offers these tips:
• When to tell: If you feel "obsessed with (a secret), dream about it, worry about it, or feel that you're worthless because of it," it's time to vent. "Physical problems, like rashes, anxiety attacks, indigestion, hives, headaches can result from the stress of a secret that is really burdensome," she says.
• How to tell: Tessina suggests approaching the person you're thinking of confessing to and saying something like, "I'd like to tell you something really personal and serious. Would you mind?" If the person backs off, you'll know it's best to keep quiet. "Get the promise to keep your secret first," she says.
• When your secret is illegal: "You can make your friend an accomplice after the fact by telling him or her a secret about an illegal situation or act," she says. "Your friend is actually bound to tell, or become part of the crime. Likewise, therapists and doctors may be legally and professionally obliged to report certain acts -- and they should tell you that before you confess to them."
• What to tell: "Confessing fears is a great way to get rid of them," says Tessina. "If you choose your confessor well, that person will be able to reassure you that you're OK, and it's not so bad. The same thing applies to shame and embarrassment. If the secret is something about who you are, not so much what you did, it's probably not such a bad thing to share."
LifeWire provides original and syndicated content to Web publishers. Sarah Jio is a Seattle-based freelance writer and the health and fitness blogger for Glamour.com.