Stress

Stress can by either physical or psychological, or both. Stress is defined as either a state of emotional or psychological strain or tension resulting from a situation or event, or the physical stress (pressure or tension) exerted on a physical object such as a part of the body, e.g., a stress test is a medical test that monitors the cardiovascular system during strenuous exercise.

Good stress
"Good" stress refers to experiences that are physically or emotionally challenging but don't last, and are within the person's ability to master, resulting in feelings of exhilaration and accomplishment. For example, running for longer than normal in order to get fitter without becoming ill or exhausted, or handling a very busy day at work successfully.

Physiological stress
Physiological stress is stress placed on living organisms, such as cells or people. Physiological stresses include physical injury to the body, surgery, walking outside in cold and wet conditions without a coat on, and malnutrition.

ME/CFS
Emotional or psychological stress, particularly when chronic, is considered a potential trigger for ME/CFS. Emotional stress is also known to worsen ME/CFS symptoms. ME patients are usually advised to avoid stress wherever possible.

Autonomic nervous system
Stress causes bodily changes via the autonomic nervous system.

Notable studies
Several studies found it is not uncommon to experience major psychological chronic stress (from events such as divorce, bereavement or serious financial worries) in the year prior to developing ME/CFS.

Chronic psychological stress elevates cortisol which suppresses the Th1 antiviral/intracellular immune response and the T-cell response. Chronic stress has also been shown to greatly increase susceptibility to viral infection. This increased susceptibility is not observed after short-term acute stress (periods of stress of less than 1 month duration).

As ME/CFS normally appears after acute viral infection, the presence of chronic stress may weaken immunity and allow a normally mild virus to trigger the serious disease of ME/CFS.

Learn more

 * Understanding the stress response - Harvard Health
 * Neuronal Responses to Physiological Stress