What is an effective measure to cool a worker suffering from heat stress?

Using ice packs on the body is an effective measure to cool a worker suffering from heat stress because it directly lowers the body's temperature in critical areas. By applying ice packs to key areas such as the neck, armpits, and groin, where blood vessels are close to the surface, it allows for rapid cooling of the blood and helps in reducing the overall body temperature. This method can be especially beneficial in acute situations of heat stress, providing immediate relief and preventing further complications.

In contrast, other options such as hot coffee can exacerbate dehydration and heat stress symptoms due to its caffeine content, which acts as a diuretic. Cold drinks, while better than hot beverages, may not be as effective if they are not applied directly to the body and may take time to have an overall cooling effect. Fans can help circulate air and evaporate sweat, but they do not actively cool the body as ice packs do. Therefore, while they may provide some comfort, the cooling effect is significantly less immediate and effective compared to using ice packs.