Plasma Catecholamine’s and Blood Pressure Changes after Prolonged Exposure to Stressful Stimuli (Heat)

Abstract

The aim of this study was to evaluate the relationships between heat stress and indicators of autonomic nervous system activity in workers of the Thermal Power Station. A total of 123 employees between 12-58yrs of age from a company that produces electricity were recruited for participation in this study. Thermal stress was assessed in workers exposed to heat to temperature between 38 0 C to 43 0 C in Boiler section. The workers were divided into four groups depending on duration of exposure. Systolic and Diastolic Blood pressure was recorded and plasma catecholamine's concentration was measured by an HPLC-ECD. Information on demographic characteristics, previous job history, smoking status and alcohol consumption was also collected. Blood pressure was significantly higher with prolonged duration of stressful (heat) stimuli.The plasma catecholamine's levels increases significantly. The results of the present study indicate that these modifications are related with the duration of exposure to heat. It is presumed that these effects are due to activation of autonomic nervous system and Hypothalamo-Hypypophyseal adrenal axis and resultant release of catecholamine's from adrenal medulla due to heat stress. These suggest that the risk of hypertension and Coronary Heart Disease (CHD) is greater in these workers.