Acute time-limited stressors involve laboratory challenges such as public speaking or mental arithmetic. The taxonomy includes five categories of stressors. This taxonomy has the advantage of distinguishing among stressors on two important dimensions: duration and course (e.g., discrete vs.
We adopted Elliot and Eisdorfer’s (1982) taxonomy to characterize these stressors. Most of the studies contributing to this review simply define stress as circumstances that most people would find stressful, that is, stressors. Our review, therefore, focuses on those aspects that are most often represented in the stress and immunity literature and therefore directly relevant to the meta-analysis.ĭespite nearly a century of research on various aspects of stress, investigators still find it difficult to achieve consensus on a satisfactory definition of this concept. Both the construct of stress and the human immune system are complex, and both could consume book-length reviews. In this article we attempt to consolidate empirical knowledge about psychological stress and the human immune system through meta-analysis. Indeed, over the past 30 years, more than 300 studies have been done on stress and immunity in humans, and together they have shown that psychological challenges are capable of modifying various features of the immune response. Threats that do not require a physical response (e.g., academic exams) may therefore have physical consequences, including changes in the immune system. However, human physiological response continues to reflect the demands of earlier environments. Modern humans rarely encounter many of the stimuli that commonly evoked fight-or-flight responses for their ancestors, such as predation or inclement weather without protection. Stress-induced changes in the immune system that could accelerate wound repair and help prevent infections from taking hold would therefore be adaptive and selected along with other physiological changes that increased evolutionary fitness.
#META ANALYSIS DEFINITION BIOLOGY SKIN#
Any wound in the skin is likely to contain pathogens that could multiply and cause infection ( Williams & Leaper, 1998). The result is physiological support for adaptive behaviors such as “fight or flight.” Immune responses to stressful situations may be part of these adaptive responses because, in addition to the risk inherent in the situation (e.g., a predator), fighting and fleeing carries the risk of injury and subsequent entry of infectious agents into the bloodstream or skin.
In mammals, these responses include changes that increase the delivery of oxygen and glucose to the heart and the large skeletal muscles.
The ability to respond to environmental threats or stressors such as predation or natural disaster enhanced survival and therefore reproductive capacity, and physiological responses that supported such responses could be selected for. Since the dawn of time, organisms have been subject to evolutionary pressure from the environment.
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