Heat illness is a cumulative and progressive range of conditions that can occur with prolonged exposure or increased exertion in hot environments. Prevention is key, and certain precautions such as limiting exposure on particularly hot days can prevent heat illness in training and during combat.
Currently, the wet bulb globe temperature (WBGT) index is the gold standard to assess environmental heat stress. Military, occupational, and sports-medicine communities use it as a guide to minimize heat strain during training and other activities. The WBGT index is usually measured at a single location as close as possible to the planned activity to assess real-time exposures. However, when the area is large, it’s crucial to monitor the WBGT at multiple locations to account for spatial variation.
Using accurate tools to assess WBGT is a critical step. Comparison of the accuracy of various commercially available WBGT monitors to a standardized reference device has shown evidence that the following monitors provide the most accurate and/or conservative estimates of WBGT:
- Extech HT30: Heat Stress WBGT Meter
- 3M QUESTemp Heat Stress Monitor Kit QT34
- Kestrel Meter 4400 Heat Stress Tracker (replaced with the Kestrel 5400 Heat Stress Tracker in 2015)
So, each of these WBGT monitors would be suitable for use under military conditions. For more information about heat injury and illness prevention, visit HPRC’s Environmental Extremes section.