<p>Chronic stress and illness are intertwined. It is well-known that psychological stress raises the risk of heart disease, cold and flu, and even allergies.<br /><br /></p>.<p>But how does one lead to the other? New research suggests that the hormone cortisol plays a critical role. Released in greater amounts in times of stress, this hormone provides the body with a burst of energy. It also helps suppress the body’s immune response to infections like the flu, keeping inflammation responses like coughing, sneezing and fevers in check.<br /><br />But when levels of cortisol remain elevated, the body may become less sensitive to it, in the same way that elevated insulin levels can lead to insulin resistance.<br /><br />Carnegie Mellon scientists tested this idea. In one experiment, 276 healthy adults were exposed to cold viruses, then quarantined and monitored for five days. The subjects who had recently been through stressful experiences were most likely to show resistance to cortisol. They were also more likely to develop colds, according to a study in The Proceedings of the National Academy of Sciences.<br /><br />In a second phase, the researchers found that the participants who were more resistant to cortisol also produced more cytokines, components of the immune system that promote inflammation and heighten the severity of symptoms.<br /><br />“Because inflammation plays an important role in the onset and progression of a wide range of diseases,” the study said, this process “may have broad implications for understanding the role of stress.”<br /><br />The verdict<br /><br />Chronic stress may raise the risk of sickness by fostering resistance to cortisol.<br /><br /></p>
<p>Chronic stress and illness are intertwined. It is well-known that psychological stress raises the risk of heart disease, cold and flu, and even allergies.<br /><br /></p>.<p>But how does one lead to the other? New research suggests that the hormone cortisol plays a critical role. Released in greater amounts in times of stress, this hormone provides the body with a burst of energy. It also helps suppress the body’s immune response to infections like the flu, keeping inflammation responses like coughing, sneezing and fevers in check.<br /><br />But when levels of cortisol remain elevated, the body may become less sensitive to it, in the same way that elevated insulin levels can lead to insulin resistance.<br /><br />Carnegie Mellon scientists tested this idea. In one experiment, 276 healthy adults were exposed to cold viruses, then quarantined and monitored for five days. The subjects who had recently been through stressful experiences were most likely to show resistance to cortisol. They were also more likely to develop colds, according to a study in The Proceedings of the National Academy of Sciences.<br /><br />In a second phase, the researchers found that the participants who were more resistant to cortisol also produced more cytokines, components of the immune system that promote inflammation and heighten the severity of symptoms.<br /><br />“Because inflammation plays an important role in the onset and progression of a wide range of diseases,” the study said, this process “may have broad implications for understanding the role of stress.”<br /><br />The verdict<br /><br />Chronic stress may raise the risk of sickness by fostering resistance to cortisol.<br /><br /></p>