"My best guess is that those most impacted by the economic downturn will be at greater risk [of cold and flu]," said Sheldon Cohen, a professor of psychology at Carnegie Mellon University in Pittsburgh, and one of the country's leading experts on the relationship between stress and vulnerability to viral infections.
In one of Cohen's studies, he looked at the types of stress factors that make healthy adults more prone to catching a cold. He said he found that chronic, enduring stressors made the biggest difference.
Short-term stressors like a traffic jam, a fender-bender, or a quick turnaround project at work happen all the time and cause small changes in immune response.
But stressors that are ongoing and lasting a month or longer -- the bad marriage, the bad working situation -- are the kind most likely to make you come down with something.
"There's a fair amount of evidence from epidemiology and viral challenge tests that people exposed to chronic stress are at greater risk of catching a cold," Cohen said.
This Is Your Immune System on Stress
The connection between stress and the sniffles is a principle with which Colleen Hughes, a 26-year-old copy editor and part-time graduate student from Sunderland, Mass., is familiar.
"I tend to be a high-stress person, and I worry a lot," she said. "But I also seem to be more productive with stress and can work a lot faster."
Hughes said her stress makes her productive on the one hand, but it also makes her "mind go a mile a minute and makes sleep harder." And it's often during these times with "one issue after another and too much to get done" that she gets "a bit of a sore throat," which is typically how her colds start to blossom.
Immune researchers agree that prolonged stress can indeed weaken the immune system.
"If you're chronically stressed, you will get worse infections and more frequent infections," said Dr. Esther Sternberg., director of the integrative neural immune program at the National Institute of Mental Health.
Key to this concept is the idea that the nerve chemicals and stress hormones (such as cortisol) affect the body's ability to fight disease and maintain health, Sternberg explained. When you have too much cortisol around because of chronic stress, it interferes with the body's ability to shut off production of pro-inflammatory cytokines, which are proteins produced by the immune system in response to infection.
Having too much of these cytokines means a viral infection and its symptoms linger -- making it harder for you to get rid of your cold.
"Stress can make you sick or help make you sick," said Janice Kiecolt-Glaser, a professor of health psychology at Ohio State University, who along with her immunologist husband Ronald Glaser, has spent several decades researching the influence of psychological stress on immune function.
In their work, they've looked at several different groups of people who experience a great deal of stress, including medical students and older adults who were caregivers. They measured how their immune systems responded when given a vaccine during high-stress times compared to their calmer counterparts.
The Glasers found that people who had more stress had a poorer response to the vaccine. In other words, they were more likely to get sick. In short, stress seemed to hinder the immune system's resistance to infections and its ability to protect itself against them.
"We were surprised at how strong and consistent the data was across groups," Kiecolt-Glaser said. "We gave different vaccines to different populations but the effect was still the same."
It's the Economy, Stupid
Cohen's research found that work-related stressors and interpersonal conflicts at home were the two most powerful predictors of who gets a cold.
Specifically though, he determined that the kind of work-related stressors that matter most are economic ones, and it's these financial concerns that can also create ongoing stressors at home.
"If you have an enduring economic stressor, you're five times more likely to get a cold than people who don't have any ongoing enduring stressors," Cohen said. His data showed that people who were unemployed or underemployed at jobs that weren't commensurate with their training were at five times greater risk of catching a cold.
As for why economic stress made you more prone to getting sick, Cohen speculated, "Our guess is that the effect of unemployment is due to the fact that it is an extremely potent stressor influencing multiple factors in a person's life including issues like self-esteem, feelings of control as well as the obvious implications for paying rent and putting food on the table."
When asked whether other enduring economic stressors facing consumers, such as a potential recession or significant drop in the stock market would have a similar impact, he replied, "It's hard to say. These are a little more abstract than being unemployed. However, they do generate some of the same threats."
Stress Relief Every Day May Keep Colds Away
If there is any silver lining to that stress-related cold, it could be that it may be a red flag for bigger stress issues that beg to be addressed.
"Sometimes a cold lets you know that you've got to do something about stress," said Dr. James Gordon, psychiatrist and director of the Center for Mind-Body Medicine in Washington, D.C. "It's important to use the experience to look at what stress is and how it could be affecting you."
When people are stressed, their health behaviors often suffer. They might not exercise, they eat the wrong foods, they don't sleep as well, and they might drink or smoke more. None of this is good for the immune system, pointed out Kiecolt-Glaser.
And she said that on the psychological side, they tend to withdraw from others.
"Those personal relationships are one of the better things you can do from the standpoint of immune response," she said.
The mind-body experts seem to agree that a good first step is being conscious that stress is going on, so that you can find ways to reduce it and be less susceptible to its effects.
"If you can downturn from the stress response and shift gears into a relaxation mode, you will go a long way toward helping your body to counter the negative impact of stress on your health," Sternberg said. You can do this in several ways, including meditation, exercise, tai chi, yoga, a healthy diet, getting together with family and friends, and prayer, she said.
Some other relaxation techniques that don't put a dent in your wallet are to take some slow, deep breaths, or to take a brief mental vacation by visualizing a favorite place, whether it's a beach, a mountain top, or your backyard garden.
Another good way to unwind that costs nothing at all is to give yourself a minute or more of silence, perhaps as you get into your car in the evening before commuting home. Don't turn on the radio or CD player and don't put the cell phone to your ear, but sit quietly and breathe deeply, allowing the stress of the day to fade away.
Taking time to relax each day could be exactly what your immune system needs to fight off colds and flu this year. And it could help you weather the economic downturn without feeling under the weather.