What is the primary preventive measure to take when the wet bulb-globe temperature index indicates high heat stress?

Ensuring adequate hydration is critical when the wet bulb-globe temperature index indicates high heat stress. This index measures the combined effects of temperature, humidity, and wind speed on the body, reflecting the risk of heat-related illnesses. During high heat stress conditions, the body loses more fluids through perspiration as it attempts to regulate its temperature. If individuals do not replace these fluids, dehydration can occur, leading to serious health issues such as heat exhaustion or heat stroke.

Maintaining proper hydration helps to keep the body's temperature within a safe range and supports essential physiological functions. Drinking water or electrolyte-replenishing beverages before, during, and after exposure to heat is a recommended strategy that can significantly reduce the risk of adverse health effects. Other strategies, such as modifying physical activity or clothing, may also be important, but without adequate hydration, the body is unable to cope effectively with heat stress.