It’s no secret that chronic stress can put a serious strain on your health. But for all the life-threatening links that scientists have exposed—from depression and heart disease to the common cold—the exact mechanism behind stress’ laundry list of devastating effects has remained a much murkier matter. At least until recently, that is.
Newly published research out of Carnegie Mellon University (CMU) has finally pinpointed at least one factor that makes stress so deadly… and begins to explain, at last, why unrelenting anxiety leaves your body so vulnerable.
The Cortisol Connection
You probably recognize cortisol as a hormone involved in your body’s stress response—a natural steroid that your adrenal glands generate as part of the fight-or-flight response. But cortisol also plays a critical role in the regulation of your body’s inflammatory response—and CMU researchers theorized that when your body experiences prolonged stress, this particular part of cortisol’s balancing act begins to fail.
They tested this theory in a pair of studies using the common cold as a model for inflammation, wherein symptoms indicate the degree of your body’s inflammatory response to viral invaders. The first study featured 276 healthy volunteers, whom researchers assessed for stressful events and glucocorticoid receptor resistance (a measure that would reveal any reduced tissue sensitivity to the hormone cortisol). The researchers then exposed the volunteers to one of two rhinoviruses and watched for symptom development.
Results of this study supported the connection between stress and inflammation, showing that subjects with recent exposure to a long-term stressor also had greater cortisol resistance—a state that renders the hormone less capable of regulating inflammation. This link was further confirmed by the fact that the same high-stress, cortisol-resistant subjects were also at significantly higher risk of developing a cold.1-2
A second study followed 79 healthy subjects—all assessed for the same variables, including glucocorticoid receptor resistance—in order to monitor the production of pro-inflammatory cytokines (including TNF-alpha and interleukin-6) in nasal secretions five days after exposure to a rhinovirus. The results of this study echoed those of the first, revealing that subjects with greater cortisol resistance also generated more pro-inflammatory cytokines in response to cold virus exposure.
Beyond the Common Cold
This study offers an easy way to assess your risk of coming down with a nasty cold. Simply put: If you’ve been dealing with shot nerves for some time, you’d be wise to wind down and treat your body with a little extra care.
But it’s not just stress’ connection to colds that has the study authors so interested. The persistent inflammation that’s triggered by stress-related cortisol resistance represents a common thread running through countless conditions. Heart disease, autoimmune disorders, Alzheimer’s, cancer—all of these fearsome diseases have links to chronic stress, too.
Now, scientists are one step closer to understanding why… and you have one more compelling reason to make your summer vacation last just a little bit longer.
2. Cohen S, et al. Proc Natl Acad Sci U S A. 2012 Apr 17;109(16):5995-9.