Last month, as the clip of Jimmy Kimmel describing the frightening ordeal of his newborn son, who was born with a congenital heart disease, went viral, many parents likely shared a similar sentiment: “What if that were my child?”

Although taking on the perspective of another person in difficult circumstances can seem to come almost automatically, a new study led by Anneke Buffone of Penn’s Positive Psychology Center suggests that this type of empathy can elicit harmful physical effects.

“This is the first time we have physical evidence that putting yourself in someone else’s shoes is potentially harmful,” she says.

In the work, published recently in the Journal of Experimental Social Psychology, Buffone and colleagues measured the physiological responses of a group of more than 200 college students who were tasked with being “helpers” to someone who recently experienced a tragic event.

Provided with a personal statement, allegedly written by their partner in the study, describing financial struggles while coping with the loss of a parent and serving as primary caregiver to a younger sibling, the study participants were tasked with reading the statement according to differing instructions based on experimental condition. One group was asked to read the statement while imagining themselves in the situation of their study partner; the second group was asked to imagine the feelings of the study partner; and the third group was asked to remain objective and detached while reading the statement. All participants were then asked to respond to their study partner via videotape in a way that seemed helpful and supportive.

The participants’ heart rate, blood pressure, and other physiological responses were measured as they spoke, and the researchers found distinct differences between groups compared to baseline assessments of the same measures. Taking on the perspective of the sufferer caused the participants to enter fight-or-flight mode, as if confronting a threat, while considering how the sufferer felt elicited an invigorating response, as if taking on a manageable challenge.

Buffone says that the “threat response” may well be debilitating over time.

“It’s stressful,” she says, “it’s something that depletes your energy.”

This type of response is associated with release of the hormone cortisol, which can induce negative health effects over the long-term.

While scientists have known that people in caregiving positions, such as doctors and nurses, can suffer from “empathy burnout,” this is the first study to demonstrate a physical difference between two types of empathy.

Buffone and her colleagues are hopeful that caregivers, including health professionals and even parents, can learn from this and future work into “good” and “bad” empathy.

“We tell our kids, ‘How would you feel if this happened to you?’” Buffone says. “But instead, maybe we should say, ‘Oh look, it seems this person is feeling sad.’ We can be empathetic by feeling for, rather than with the other person.”