Studying the Effects of Exercise during Exposure to Inhaled Pollutants Using Animal Exposure Models
CALIFORNIA UNIV IRVINE DEPT OF COMMUNITY AND ENVIRONMENTAL MEDICINE
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During exercise several events can dramatically change the effects of inhaled toxic substances. Increased respiratory ventilation exposes an individual to a larger inhaled dose of an airborne compounds, and the dose rate may be many fold greater than resting exposure. Biological effects may not be simply proportional to increased dose rate due to exercise ventilation. Greater depth of breathing, decreased contact time between inspired air and upper airways, and an increase in the fraction of air drawn through the mouth rather than the nose result in alteration of deposition efficiencies of gases and particles in the respiratory tract and changes in the distribution of inhaled dose. Any protective breathing patterns operating at rest in response to irritant compounds may be overridden by the demands for increased gas exchange while exercising. Thus, the health risk of exposure during exercise may be considerably greater than predicted by simple proportion to inhaled dose. Inhalation studies of air pollutant compounds with human subjects frequently used exercise exposures, and they have typically demonstrated greater responses during exposures at exercise than were observed at rest. The purpose of this presentation is to describe some of the ways in which exercising animals can be applied to inhalation toxicology.
- Stress Physiology
- Air Pollution and Control