ABSTRACT
Noise stress, reviewed in the previous chapter, is just one example of a physical stressor. By a physical stressor, we mean a stressor associated with the external environment defined by its objective physical properties. Some physical stressors may be psychophysically defined: they are potentially disturbing because of their stimulus properties, such as the intensity of a bright light. Other physical stressors are more insidious, in that they operate primarily through physiological change rather than through the senses. Certain chemical toxins may affect brain functioning without the person necessarily being aware of their influence. Some stressors exert both types of influence. As we shall see, heat generates thermal discomfort, in relation to its psychophysical intensity, but may also influence the brain through changes in thermoregulation.
