Researchers at the National Centre for Complementary & Alternative Medicine (NCCAM) at the National Institute of Health (NIH) in the United States have found that chronic psychological stress impacts our molecular immune system response, increasing likelihood of developing cold symptoms.
More stress means more glucocorticoids, like cortisol, the classic stress hormone. Cortisol’s role is to decrease inflammation in short bursts, to allow us to escape the theoretical physical stressor. However with longer term psychological stress, cortisol stays elevated. Our system adapts by becoming less responsive to the stress hormones (this is called glucocorticoid receptor resistance in the study). Researchers have now discovered that the less responsive someone is to glucocorticoids (ie, the more glucocorticoid receptor resistance they have), the more inflammatory molecules they produce in response to a common cold virus, and thus the more likely they are to have symptoms of this cold.
Bottom line: we were right. High stress or burning the candle at both ends can make you sick.