NATICK, Mass. (Oct. 24, 2016) -- Every Soldier is different, and this cannot be more evident when troops deployed to the same mountainous terrain experience symptoms of Acute Mountain Sickness.
For some Soldiers, the headaches, vomiting, fatigue, exhaustion and trouble sleeping are so severe they need to be put on supplemental oxygen. Other Soldiers might experience less-severe symptoms or even feel completely fine.
Now, researchers from the U.S. Army Research Institute of Environmental Medicine, USARIEM, are beginning to solve this puzzle after concluding their field study in the Maher Memorial Altitude Laboratory on the 14,115-foot summit of Pikes Peak in Colorado.
"We are striving to create a look-ahead model that has been tailored to an individual based on their physiology," said Dr. Mark Buller, a research psychologist with USARIEM's Biophysics and Biomedical Modeling Division, or BBMD. "The system will measure parameters like heart rate and oxygen saturation to provide some prediction of when and how severe Soldiers could suffer from AMS."
In July 2016, researchers from BBMD along with Dr. Beth Beidleman, the principal investigator of the study conducted on Pikes Peak, used wearable physiological status monitors to collect real-time, minute-by-minute heart rate, blood-oxygen saturation levels, respiration rate, skin temperature, core body temperature and body position.
Researchers collected these real-time physiological data at sea level, during the first two days on the peak (when AMS symptoms are usually the most severe) and then again during a 24-hour exposure in the USARIEM hypobaric chamber after a 12-day period of de-acclimatization. The data will be used to develop an algorithm that can predict the likelihood of health and performance decrements in individuals exposed to a hypoxic environment.
"BBMD likes to use the analogy of a car," Buller said. "A car has gauges that provide information on how it is working, such as how hot it is getting or how hard the engine is working. With a person, you do not really have those gauges or know where they are in terms of their health and performance. Physiological status monitors are being developed to provide that information.
"If a Soldier goes to altitude, a physiological status monitor can provide that situational awareness of their health and performance and their predicted likelihood of AMS, so commanders can take action based upon that information. Mission planners will not be caught off guard by having half of their troops suffering from AMS."
Back at USARIEM, BBMD researchers are now processing the data and getting into the mathematical development of the model. According to Buller, BBMD plans to apply their modeling skills to other extreme environments in future studies.
"As we combine all of these different aspects, we now begin to have a much more comprehensive view of the warfighter," Buller said. "Rather than just applying physiological status monitors to thermal environments, we are dealing with how nutrition, hydration and physiological status relate to Soldier readiness in a host of extreme environments. If mission planners are given a particular mission and know the Soldier's state, they can use the models to optimize the mission and complete it in the least-stressful way for the Soldier.
"USARIEM is moving toward more individualized health modeling, which not only takes into account the individual responses, but also how those responses change over time and in response to external stimulation. When you have a biomedical model that works for a group, it might work for 80 to 90 percent of the Soldiers. However, you are going to miss the Soldiers who respond outside of the normal range. We want to adapt our models to accurately capture individual Soldiers' differences and responses. These types of models will allow the possibility of adapting treatments so they become as unique as the individual."
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