As a heat wave is settling over the area this week, several fall athletic contests were canceled on Monday or pushed back to have times closer to dusk, practices were changed or not held and four words start floating around not normally hear – wet bulb globe temperature. With this now being two years in a row that a late August or very early September heat wave has been seen in the Midwest, heat safety guidelines are in the spotlight. So what is wet bulb globe temperature (WBGT) and how is it guiding what happens with area school sports and athletes? The National Weather Service explains WBGT as being “a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas.”
With schools equipped with wet bulb globe temperature devices, the IESA and IHSA uses guidelines that coincide with the four WBGT risk levels. Any WBGT level of below 80 degrees, which is again a temperature calculated by the five different weather factors, is no risk level. The WBGT low risk level of 80-85 degrees coincides with the “yellow” level of 80-84.5 degrees for IESA/IHSA which calls for discretion for intense and prolonged exercise and frequent water breaks. At the WBGT moderate risk level from 85-88 that coincides with the “orange” level of 84.6-87.5 degrees for IESA/IHSA calls for no contests to be held and for there to be 20 minutes of mandatory water breaks for each hour of practice with practice capped at two hours. At the WBGT moderate risk level from 89-90 that coincides with the “red” level of 87.6-89.9 degrees for IESA/IHSA calls for no contests to be held and for there to be 20 minutes of mandatory water breaks for each hour of practice with practice capped at one hour and also says that no conditioning be completed ad no protective equipment be worn during the one hour practice. The final level or “extreme risk” of any WBGT over 90 degrees or 89.9 degrees and higher for IESA/IHSA calls for no outdoor practices, workouts or games/matches/meets so all outdoor activities must be canceled or postponed.
To read the full IESA and IHSA managing heat illness guidelines, go to https://www.iesa.org/documents/health/IESA-ManagingHeatIllness.pdf
