Wearable Device to Prevent Heat Stroke Among Military Servicemen

Photo illus. Vigilant Guard 2015, South Carolina
U.S. Air Force Airman 1st Class Ishmael Gutierrez assigned to the 169th Medical Group, South Carolina Air National Guard, assists first responders in first aid to simulated victims during the Vigilant Guard South Carolina exercise, in Georgetown, S.C., March 8, 2015. Vigilant Guard is a series of federally funded disaster-response drills conducted by National Guard units working with federal, state and local emergency management agencies and first responders. (U.S. Air National Guard photo by Tech. Sgt. Jorge Intriago/Released)

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Heat stroke or heat exhaustion injuries pose a significant health threat to soldiers, and young or inexperienced recruits are especially vulnerable. Hundreds of US services soldiers have these injuries each year, and annually a number of service members have died from this. 

A new device from MIT Lincoln Laboratory can now alert trainees when they are heading toward injury. 

The device continuously estimates a person’s core body temperature to determine their risk level for heat strain as they train. This risk is communicated on a smartwatch display, providing early warning to its wearer. 

The system is made up of a few components. First, an armband sensor measures the trainee’s heart rate. Those heart rate data are sent via Bluetooth to a smartwatch. Installed on the watch, a Lincoln Laboratory-developed app runs an algorithm that uses the data to estimate core body temperature. Depending on those results, the smartwatch will display a visual icon with a colored background (red, yellow, or green) and emit an audible tone to alert users if they are overheating.

This technology was developed under the sponsorship of the U.S. Army Medical Materiel Development Activity and in partnership with the U.S. Army Research Institute of Environmental Medicine. 

In October, the technology was transitioned to the U.S. Marine Corps Training and Education Command, which have so far fielded 170 prototypes at basic training sites. Feedback has been positive, with recommendations to enhance the capability, according to mit.edu.

The algorithm this device uses to estimate core body temperature was developed by the U.S. government in 2013. It has since been used in many commercial products. This device, however, is the first use of the algorithm in a form factor as small as a smartwatch.