Impact of heat stress on thermal balance, hydration and cortical response among outdoor workers in hot environment - an exploratory report from North East India.

Objective: The objective of our study was to assess the impact of heat stress on hydration and cognition among outdoor workers in hot environment.

Methods: Area heat stress assessments were measured using Quest Temp WBGT monitor. Sweat rate for dehydration and reaction time for acute cognitive processing were recorded using standard procedures.

Results: Heat stress measurements ranged from 23.8 °C - 42 °C. More than 50 % of the workers had high sweat rate (>1.2 L/h) when exposed to high environmental temperatures. Positive correlation was obtained between WBGT, sweat rate and reaction time which indicates that hyperthermia has an impact on neural network processing. Heart rate and reaction time also increased with rise in WBGT and heavy physical activity.

Conclusions: There was impairment of cognitive functions (reaction time) under heat stress conditions. Hence, reaction time can be used to assess the short-term impact of heat stress on neural modulation and will help to plan effective intervention strategies to reduce morbidity and mortality among workers.