Burnout represents a state of emotional and physical exhaustion typically triggered excessive and prolonged stress. It can produce a sense of hopelessness and helplessness in which emotions are blunted and there is a loss of motivation and ideals. Over time it can lead to profound depression and/or a sense that life is not worth living. It can also contribute to serious physical illness. (Preventing Burnout: Signs, Symptoms, and Strategies to Avoid It. Provided by HelpGuide.org, Article)
Burnout resulting from excess stress is a clear risk factor for heart disease and is characterized by fatigue. (Hafen, Brent Q., et al. Mind/Body Health. MA: Simon & Schuster, 1996, pp 81, 90-92)
Burnout is a term for a condition characterized by long-term exhaustion and diminished interest. Maslach and Jackson identified this condition in the 1970’s. The Maslach Burnout Inventory weighs the effects of emotional exhaustion (hallmark symptom), depersonalization, and reduced sense of personal accomplishment). It has become the standard tool for measuring burnout in research on the syndrome. Source.
Refer to Burnout and the Brain for additional information.