AUGUST 24, 2021 – Scientists from the U.S. Army Research Institute of Environmental Medicine conducted an altitude study in Taos Ski Valley, New Mexico, this summer with 41 Soldiers from the 5th Engineer Battalion. The research team is finalizing a tool that can predict acute mountain sickness, or AMS, in individuals.
Anyone who has rapidly ascended to high altitude may experience the telltale signs of AMS. People can experience headaches, nausea, fatigue, poor sleep, shortness of breath and neurocognitive impairments as their bodies adjust to the lower oxygen pressure. Symptoms typically peak after the first night of sleep at altitude and can last up to 72 hours. Gradually, the body learns how to adapt to this environment, and symptoms typically subside.
AMS is an additional challenge for warfighters, who regularly face life-and-death situations during military operations. Dr. Beth Beidleman, the study’s principal investigator, said AMS occurs because less oxygen gets to critical organs, like the muscles and brain, debilitating performance.
“About 50 to 90 percent of unacclimatized warfighters will experience AMS symptoms when ascending to high altitude, depending on the altitude attained,” said Beidleman, a USARIEM research physiologist. “AMS will impact every aspect of a warfighter’s performance. They won’t be able to physically or mentally perform well.”
USARIEM has spent decades learning how the human body adapts to high altitudes. While AMS is common, Beidleman and other researchers have observed how symptoms vary from person to person. Some people might not experience any symptoms at all. Others may require a medical evacuation.
The tool, called the AMS-alert, would be the first algorithm to predict individuals’ AMS risk in real-time. When implemented into a smartwatch or smart fabric, military leaders could use the algorithm to identify warfighters at high risk of experiencing AMS. Military leaders could intervene and prevent casualties before warfighters deploy to high altitudes.
According to Beidleman, AMS-alert can identify a high-risk person with 83 percent accuracy. However, to provide personalized solutions for warfighters, the researchers needed a bigger data set to validate these original predictions.
USARIEM collaborated with Taos Ski Valley, the University of New Mexico’s International Mountain Medicine Center and the 509th Clearance Company in Fort Leonard Wood, Missouri, to run the Taos study and improve the algorithm.
“To move altitude research forward, we need to study larger populations at other high-altitude sites that are more applicable to the warfighter,” Beidleman said. “The environment at Taos Ski Valley was an ideal place to accomplish this mission. By getting more data from more warfighters at new locations, we can improve the algorithm’s accuracy in predicting AMS in individuals.”
The Soldiers either ruck marched or were transported to Kachina Peak at 11,800 feet above sea level just hours after arriving in New Mexico. The researchers tested the Soldiers’ physical and cognitive performance throughout the four-day study.
The researchers equipped the Soldiers with monitors on their ankle, chest, wrist and index finger to ensure they got the most data from this study. The Soldiers wore the monitors for the entirety of their stay. These monitors tracked vital data, such as breathing, heart rate, physical activity and sleep disturbances.
USARIEM is also collaborating with the Walter Reed Army Institute of Research and the Air Force Research Laboratory to perform genomic testing, which involves looking at how RNA functions and interacts with a person’s body. The researchers collected and analyzed saliva, urine and stool to identify biomarkers that signify a person is at high risk for AMS.
“High-risk people could have a common genomic pathway that makes them more susceptible to AMS,” Beidleman said. “If we could identify that pathway, the Military could have a non-invasive way of identifying those high-risk individuals and preventing casualties.”
AMS-alert is the latest prediction algorithm USARIEM has developed to help units plan missions in extreme environments. An earlier planning tool is the Altitude Readiness Management System, or ARMS, a smartphone app military leaders can use to predict the percentage of AMS in units. Currently, warfighters can download ARMS through the TRADOC App Gateway.
Beidleman said that AMS-alert would take altitude mission planning to the next level. The tool would take the guesswork out of determining who will actually suffer with the most severe symptoms.
“Our team has accomplished a lot during the study to validate and improve the AMS-alert algorithm,” Beidleman said. “This individualized algorithm will prevent AMS and optimize performance in warfighters deployed to the mountains in the years to come. It will also provide a technological breakthrough in physiologic monitoring for the U.S. Military, civilian healthcare providers, mountaineers, recreational athletes and search-and-rescue teams.”
Story by Mallory Roussel
U.S. Army Research Institute of Environmental Medicine