Doctors have long thought that stress exacerbates the symptoms of many auto-immune diseases, and now they’ve found evidence linking it to the common cold, as well.

It seems people under chronic personal or professional stress are more likely to have persistent cold symptoms after exposure to the virus than other people. Experts blame the stress hormone cortisol, which acts as the “off switch” for our inflammatory response. If we produce too much cortisol, our immune systems become resistant and less able to fight off those sniffles and sneezes.

“The symptoms of a cold are not caused directly by the virus, they’re caused by the inflammatory response to the infection,” said Sheldon Cohen, a professor of psychology at Carnegie Mellon University in Pittsburgh and lead author of the study. “This really suggests inflammatory diseases, like asthma, autoimmune disease, cardiovascular disease, would most likely be affected by stress.”

Dr. Redford Williams, director of Duke University’s Behavioral Medicine Research Center, said the link between stress and disease is well-known, but researchers have only recently begun to uncover how they’re connected.

“As we learn more about that, I think we’ll be able to design interventions that are more likely to be effective,” he said. “We will enter an era of personalized medicine where we’re able to prevent the disease from ever starting.”

[ABC News]