I had no idea, but player overheating, better known as heatstroke, is a serious issue on the football field.  Monitoring a player’s temperature can be challenging and perhaps even down right demoralizing.  HOT (heat obvservation technology) from Hothead uses an RFID transponder with a thermal heat sensor built-in to the helmet to remotely monitor the player’s body temperature.  Info is transmitted to a handheld device and if all is normal the player is represented by a green dot, red and the player is in danger of heat stroke and an audible alarm is emitted.  Hothead has plans to test the technology in other applications such as fire fighting and the military, but currently doesn’t have a release time line or price.

[Wired]