How stress affects your body

By Mayo Clinic staff

After you've fought, fled or otherwise escaped your stressful situation, the levels of cortisol and adrenaline in your bloodstream decline. As a result, your heart rate and blood pressure return to normal and your digestion and metabolism resume a regular pace. But if stressful situations pile up one after another, your body has no chance to recover. This long-term activation of the stress-response system can disrupt almost all your body's processes, increasing your risk of obesity, insomnia, digestive complaints, heart disease and depression.
Digestive system. It's common to have a stomachache or diarrhea when you're stressed. This happens because stress hormones slow the release of stomach acid and the emptying of the stomach. The same hormones also stimulate the colon, which speeds the passage of its contents. Chronic stress can also lead to continuously high levels of cortisol. This hormone can increase appetite and cause weight gain.
Immune system. Chronic stress tends to dampen your immune system, making you more susceptible to colds and other infections. Typically, your immune system responds to infection by releasing several substances that cause inflammation. In response, the adrenal glands produce cortisol, which switches off the immune and inflammatory responses once the infection is cleared. However, prolonged stress keeps your cortisol levels continuously elevated, so your immune system remains suppressed.
In some cases, stress can have the opposite effect, making your immune system overactive. The result is an increased risk of autoimmune diseases, in which your immune system attacks your body's own cells. Stress can also worsen the symptoms of autoimmune diseases. For example, stress is one of the triggers for the sporadic flare-ups of symptoms in lupus.
Nervous system. If your fight-or-flight response never shuts off, stress hormones produce persistent feelings of anxiety, helplessness and impending doom. Oversensitivity to stress has been linked with severe depression, possibly because depressed people have a harder time adapting to the negative effects of cortisol. The byproducts of cortisol act as sedatives, which contribute to the overall feeling of depression. Excessive amounts of cortisol can cause sleep disturbances, loss of sex drive and loss of appetite.
Cardiovascular system. High levels of cortisol can also raise your heart rate and increase your blood pressure and blood lipid (cholesterol and triglyceride) levels. These are risk factors for both heart attacks and strokes. Cortisol levels also appear to play a role in the accumulation of abdominal fat, which gives some people an "apple" shape. People with apple body shapes have a higher risk of heart disease and diabetes than do people with "pear" body shapes, where weight is more concentrated in the hips.
Other systems. Stress worsens many skin conditions — such as psoriasis, eczema, hives and acne — and can be a trigger for asthma attacks.