During the next month, thousands of high school and college football teams will get ready for fall by practicing in torrid conditions where heatstroke is a constant danger.
That has some trainers and doctors worried about some thermometers that, in their view, sacrifice accuracy for convenience.
The devices use infrared light to scan heat radiation in the ear or on the forehead. The infrared thermometers have produced lower readings in athletic settings -- or in lab tests meant to simulate them -- than rectal thermometers or other devices.
After testing a widely marketed forehead scanner made by Exergen, researchers at the Institute for Exercise and Environmental Medicine at Presbyterian Hospital in Dallas warned that low readings from the device could deprive patients of critical, perhaps lifesaving medical care.
In the test, reported in the journal Medicine and Science in Sports and Exercise, the infrared thermometer gave readings below 100 degrees Fahrenheit when rectal thermometers topped 104 degrees, a temperature at which some patients begin to be vulnerable to heatstroke.
Exergen pointed out that the thermometer, the Temporal Scanner, was not marketed for use in athletic settings and came with instructions stating that it was not for outdoor use. That goes for both the consumer version, which costs $30 to $50 at drugstores and other chains, and a more durable model sold for about $350 to doctors' offices and hospitals.