District athletic trainers detail wet-bulb globe protocol and heat-safety thresholds

Lance McNamara, health service manager and athletic trainer for Bexar County School System, briefed the board on Sept. 2 about the district’s heat-safety practices and the wet-bulb globe temperature (WBGT) device the trainers use to set activity modifications.

McNamara said WBGT “gives a number” that determines activity flags: green, yellow, orange, red and black. He described a black-flag threshold at a WBGT value of 92, at which “there’s no physical activity whatsoever.” For red-flag conditions (approximately 90–92), he said activity is limited by time — athletes “do not allow athletes to participate in the weather for more than 60 minutes” and must remove equipment and have water-rest breaks embedded in sessions. He described orange (about 86–89) as requiring attention to at-risk individuals and multiple water breaks, and yellow (below about 86) as discretionary with routine hydration and monitoring. McNamara also described a “cool zone” procedure, including a shade tent and a water-immersion tank with about 30 gallons of ice water at roughly 58 degrees to lower core temperature when needed.

McNamara said the district’s trainers and coaches monitor conditions and implement unlimited water breaks and other modifications to protect student-athletes. He framed WBGT as a more comprehensive metric than heat index because it accounts for radiance, humidity and dry temperature. The presentation closed with McNamara’s summary that the school system is “committed to student safety, not just in the classroom, but also in the athletic environment.”

The board did not take action during the presentation; McNamara’s remarks described routine operational protocols and equipment available to trainers and coaches.