Jennifer Mathews: It's a coacher's job to push his athletes but how do you tell when a good practice turns dangerous. Overheating can be fatal. It killed NFL player Kory Stringer and a freshman football player in Florida in 2001.

Jim Leavitt: I have been coaching for 30 years and I trained nothing like ever happens.

Jennifer Mathews: That's why Coach Jim Leavitt had his players test a new technology to reduce heat illness in athletes. Ten players, the bigger at risk guys swallow a capsule like this one, about two hours before practice.

Jennifer Mathews: The pill which contains a battery and an electronic transmitter travels into the intestines so it isn't affected by the cold water player's drink. At practice trainers hold an electronic sensor close to the players backs and crystals inside the pill sense body temperature.

Eric Coris: Start to get concerned around 102 and then particularly 103 is typically where you will pull people away from activity.

Jennifer Mathews: Through a radio frequency signal, the pill transmits information which is tracked on a laptop.

Eric Coris: This gives us an additional tool that try to head off severe problems before they develop.

Jennifer Mathews: NASA developed the technology called CorTemp in the 80s.

Eric Coris: The technology however has become more affordable and more portable to a point where we can actually use it in this kind of environment.

Jennifer Mathews: And doctors hope it will help them better understand how to keep athletes out of trouble in the heat. This is Jennifer Mathews reporting.