Environmental effects on brain function.

Environmental extremes can result in local and systemic illness, or even death. A majority of cases involving environmental mishap are related to excessive heat, cold, or high altitude exposure. Heat- or cold-related illness occurs when the body's homeostatic mechanisms are overwhelmed, resulting in an accumulation or loss of heat, respectively. Altitude illness results from a combination of low temperature and hypoxia. All three environmental injuries have significant effects upon brain function. This article discusses the pathophysiology of heat, cold, and altitude illness and their effects upon brain function.