How many days are required for workers to acclimatize to heat?

Many research studies require recruiting heat-acclimatized workers to participate in heat-stress experiments and application fields. A reliable heat acclimatization program for workers in countries with hot environments has not been reported yet.

The objective of this study was to estimate the effects of heat stress and the amount of acclimatization required in hot-climate countries.

Eighteen male workers from an industrial population participated in this experiment. Nine days of exposure to a hot environment (wet-bulb globe temperature, 30°C) was the independent variable. The participants' cardiac costs and increment aural-canal temperatures were the dependent variables.

The study results revealed that 5 days of exposure to heat sessions were sufficient to heat acclimatize the workers based on their physiological responses (i.e., heart rate and aural-canal temperature).

According to the available literature, workers in hot climate countries, similar to the study cohort, can heat acclimatize faster than those in other Western countries.