What is stress? First, I think one of the best descriptions of stress is as a state in which the body is having to work harder to regulate itself, or a state of "threatened homeostasis
". Homeostasis is the maintenance of a constant internal environment.
What does stress do? The body does go into a "fight or flight" response, or sympathetic dominance, when exposed to stressors (particularly when there is a low supply of available glucose). A variety of hormones are released, including adrenaline, cortisol,and norepinephrine. Cortisol is the most well known stress hormone.
Hans Selye's General Adaptation Syndrome reflects what happens physiologically during stress, both acute and prolonged. Stress hormones, such as cortisol, have a negative impact on the immune system and gastrointestinal system (Selye suggested that areas such as the thymus, lymph, and stomach lining atrophy fairly early on in the stress response). Recent research confirms Selye's conclusions. Specifically, a recent article (2011) in Science Daily discusses a study which shows that stress affects the balance of bacteria in the gut and immune response. Specifically, stress caused an increase in potentially pathogenic bacteria such as Clostridium, and reduced the diversity of gut bacteria. Further, the researchers found that lowering bacteria helped the body with it's "innate immunological stress response". In other words, having a balanced ecosystem in the stomach and intestines prior to stress exposure apparently prevents some of the negative consequences of stress on the immune system. Take home message: Keep your gastrointestinal tract healthy (including the balance of bacteria) and stress will affect you less. To read the article, click on this link: