Human parotid alpha-amylase secretion as a function of chronic hyperbaric exposure.

Secretion of alpha-amylase by the human parotid gland increased significantly during eight days of hyperbaric exposure. This hyperactivity of the parotid gland presumably resulted from increased autonomic nervous system (ANS) activity attributable to (1)psychological stress in the form of anticipation; (2) dive-related factors, i.e., hyperoxia, PN2, physical stress; or (3) a combination of both. The etiology of the effect must await additional studies, but a consistent and significant elevation in alpha-amylas secretion was found. This previously undescribed effect of hyperbaric exposure indicates that parotid alpha-amylase sampling holds promise as a noninvasive means of monitoring physical and psychological stress, and as an indirect measure of ANS tone.