AUSTIN (AP) — With afternoon temperatures sizzling around 100 degrees and the heat index pushing as high as 127, about 20 Texas Longhorns pop a little white pill before they strap on their helmets for practice.

This is no medicine. About the size of a thimble, it is a miniature mechanical tool that helps players avoid heat stroke during rigorous workouts in the hottest time of year.

Covered with epoxy to aid swallowing, the pills contain a battery, a communication coil, a circuit board and a quartz crystal. A hand-held monitor placed next to the player’s midsection reads the level of vibrations from the crystal, translating it to a digital temperature reading.

It’s all about keeping early tabs on the interior body temps, even when a player may not be showing any exterior signs of distress, Texas trainer Kenny Boyd said.

“They may not look any different from any other guy, but the numbers tell you otherwise,” Boyd said.

The technology was initially developed for NASA in the 1980s to monitor body temperatures of space shuttle astronauts. The pills are now manufactured by Palmetto, Fla.-based HQ Inc., which began marketing to sports teams about three years ago, said Susan Smith, sales and marketing manager for the company.

The Longhorns started using them in the spring of 2006. Not every player takes one. Players are selected based on their history with heat stress, body mass index and other known medical conditions such as sickle-cell trait.

Big guys — linemen — are the most likely candidates. So are freshmen, players the staff have little experience monitoring.

“Guys who are carrying a lot of weight in general are the guys who tend to overheat quicker,” Boyd said. “And it’s the fear of the unknown with freshmen.”

Once the pills are ingested, the trainers move through practice checking temperatures. Although 104 degrees is considered a clinical sign of stress and that a player is starting to overheat, Boyd said Texas uses 103 as its cutoff. Players are taken to the sideline to be given fluids and ice and held out until they cool down. The Longhorns use the pills in games as well.

“It feels weird when you sit down and think about it because there is a device in your stomach that is connecting to a device outside of you. That concept kind of freaks me out, but it is definitely a positive thing,” linebacker Drew Kelson said.

Boyd said a handful of Big 12 schools use the pills but the numbers are low nationwide. According to Smith, only about 25-30 professional and college football teams use them.

Cost is a factor, Smith acknowledges. The pills cost $30 each and although they do not dissolve in the body, the Food and Drug Administration requires they be discarded after one use.

At prices like that, schools such as Texas, with one of the largest athletic department budgets in the country, are among the few that can likely afford it.