The first plunge into icy water is a shock to the system. For a warfighter operating in extreme cold-weather environments, a fall into near-freezing seas isn't a mishap; it's a life-or-death battle that is won or lost in the first
few minutes.
Naval Health Research Center (NHRC) scientists spent six days this winter at the Marine Corps Mountain Warfare Training Center (MWTC) in Bridgeport, California, doing research in the Sierra Nevada. Working in air temperature hovering at 19 degrees Fahrenheit and with water temperatures at 34 degrees, researchers are working to give U.S. warfighters the tools to win that battle.
The project, funded by the Office of Naval Research (ONR), is directly aimed at improving survival rates in a mass casualty incident at sea, such as a torpedoed ship in Arctic waters. Researchers from NHRC’s Environmental & Thermal Physiology team are researching cold-environment survival to understand and defeat a silent killer known as the "cold shock response."
"Most people's first worry is hypothermia, but in order to actually become hypothermic, you have to survive the cold shock response," explains Rebecca Weller, a research physiologist with NHRC. "The initial moments in cold water are often the most dangerous, and how you control your breathing in those moments can determine whether you survive."
That initial, involuntary gasp for air upon hitting cold water, the rapid and uncontrolled breathing (hyperventilation), and the spike in heart rate and blood pressure are all hallmarks of the cold shock response. This physiological response can quickly lead to aspirating water, cognitive impairment, and drowning. Research suggests that this response is the cause of death in up to 60% of accidental cold-water immersions, long before the body's core temperature begins to drop.
NHRC's Environmental & Thermal Physiology team led by principal investigator Doug Jones, partnered with the MWTC to conduct a vital study during its Cold-Weather Medicine Course. Students (mostly Navy Corpsmen) enrolled in the course prepared for the rigors of cold-weather operations and also had the opportunity to volunteer to serve as subjects of an experiment designed to find a simple, effective defense against cold shock.
The day before a planned cold-water immersion, study participants underwent baseline testing for stress, anxiety and information recall. They also received specialized training in a simple, powerful technique: slow-paced breathing.
The next morning, volunteers were fitted with an array of sophisticated data-collection devices—Polar heart rate straps, BodyCAP core temperature sensors, and iButton skin temperature monitors. The most critical piece of equipment, however, was a spirometer, which measures the volume and rate of breathing. The goal was to see if a simple breathing exercise could override the body's instinct to panic.
"We are trying to develop a technique and strategy that can limit the stress associated with accidental cold-water immersion," said Jones.
NHRC is currently in the process of analyzing data from these tests. Based on preliminary review of the data, the group trained in slow-paced breathing appears to have demonstrated a lower and more controlled breathing rate during the immersion compared to the untrained control group. They were actively using the technique to fight the body's involuntary response.
The team is now analyzing how controlled breathing impacts the cold shock response and operational performance, such as completion of the 9-Line task. During the immersion, participants were tasked with performing a "nine line" medical evacuation request—a standard military procedure that requires clear thought and precise communication. The ability to perform such a task under the intense physiological stress of cold shock can mean the difference between life and death for a service member.
The findings from this research will provide evidence-based data to validate and refine training protocols across the U.S. military. The ultimate goal is to provide the military with evidence-based tools that can be quickly taught to any service member and integrated into official guidance like the U.S. Navy's Cold Weather Handbook for Surface Ships, to add strategies for surviving the initial moments of cold-water immersion.
“How you control your breathing in those initial moments of cold-water immersion can determine whether you survive it,” Weller emphasized. “By practicing these techniques in a controlled environment, service members may gain the confidence and muscle memory to execute them when it counts.”
These NHRC findings will educate a new generation of warfighters—more prepared, more adaptable, and more lethal, armed with the knowledge to conquer one of nature's most unforgiving environments. They are proving that in the face of the cold's deadly gasp, the most powerful weapon can be a single, controlled breath.
Through a wide range of research, including its cold-water immersion studies, NHRC develops strategies that enable the warfighter to overcome the many health and performance-related challenges they face in the course of their duties. This research provides U.S. Naval, Marine Corps and joint forces with the opportunity to develop tools to maintain cognitive function and enhance survivability in the most extreme maritime environments.
| Date Taken: |
03.10.2026 |
| Date Posted: |
03.10.2026 14:54 |
| Story ID: |
560221 |
| Location: |
BRIDGEPORT, CALIFORNIA, US |
| Web Views: |
31 |
| Downloads: |
1 |
PUBLIC DOMAIN
This work, Mastering The First Breath: Navy Medicine Research Fortifies the Warfighter Against the Cold's Lethal Shock, by Matthew Reyes, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
