Army armor recruits at Fort Moore, Ga., practice arm immersion cooling June 29, 2023, during their Thunder Run as part of Armor One Station Unit Training. The practice is meant to prevent recruits from overheating on hot days. (Patrick A. Albright/U.S. Army)

ATLANTA — The U.S. military has not altered its training schedule during the summer despite soaring temperatures that have broken records daily across the United States, Pentagon officials have said.

“There’s no single [wet bulb globe temperature] where the Army says stop training,” Lt. Col. David DeGroot, who leads the Army Heat Center, said about a temperature measurement that takes various factors into consideration, including humidity, wind speed and sunlight. “The military has to train, but commanders need to have resources to make that risk assessment based on what they're doing.”

Service officials have spent recent years at the Army Heat Center at Fort Moore, Ga., working to improve the military’s ability to train safely in high heat and rapidly respond when troops get overheated, said DeGroot, who has directed the center since its inception in 2019.

This summer, DeGroot, an Army physiologist, has spent time at Fort Moore, formerly Fort Benning, teaching drill instructors and leaders across the Army and other military services on heat mitigation amid the hottest months in Earth’s recorded history.

DeGroot said he has helped develop two methods to prevent and treat heat injury among training troops — arm immersion cooling and ice sheeting. He has spent recent years imploring military leaders to implement them in extreme heat. Both cooling methods were detailed in the latest heat instruction released last month by U.S. Army Training and Doctrine Command, the four-star command that oversees all the service’s training schools. DeGroot helped craft the guidance.

Both cooling practices are fairly simple, he said. In arm immersion cooling, troops soak their arms in cold water during a break from training to help lower their core temperature, DeGroot said. The aim is to lower body heat by 1 degree. The Army has developed a patented device to use for arm immersion, but DeGroot said it can also be accomplished simply with a bucket of ice water.

At Fort Moore, drill instructors have implemented arm immersion into its various training courses when recruits and soldiers are working outside in the heat and humidity, said Sgt. 1st Class Richard Spencer, the safety manager for the post’s 198th Infantry Brigade, which oversees recruit training. While recruit training company commanders have leeway to implement how arm immersion is used, all are having their soldiers do it at least twice while they are out on training ranges on warm days, he said.

“If it's something like a static range where they're not moving anywhere, where they’re going to a platform, and they're firing [weapons], most of the companies are going to have them arm immerse before going out on that range,” Spencer said. “Then they would be out there for probably 15 to 20 minutes, and then they’re probably going to come back and arm immerse again after that, so it’s preventative.”

Ice sheeting is used when a soldier is already experiencing a heat injury. As soon as the soldier is found to be suffering from a heat injury, that person should be stripped down to their underwear and covered in frozen bed sheets, DeGroot said. The sheets must be changed out to cooler sheets every three or so minutes until emergency responders can evacuate the heat-injured person, he said.

Fort Moore has seen an uptick this month in incidents that result in the use of ice sheeting, Spencer said. Recruits and drill instructors are trained to ice sheet anyone suspected of suffering even a minor heat injury, he said.

“We are not medical professionals so if anyone suspects there is a potential heat illness in our formation, we will react,” Spencer said. “When it comes to heat illnesses and injuries, overreacting to minimize the severity of a potential heat injury is better than to later find out someone has organ damage because we did not react fast enough.”

Since June 1, the 198th Brigade has used ice sheeting to cool 50 recruits suspected of heat injury, including 32 this month, Spencer said.

“The single most important thing for a heat casualty is to get them cooled off,” DeGroot said.

While full body cold water immersion is the gold standard for quickly cooling the body after a heat casualty, he said that is unrealistic in a training or tactical environment. Ice sheeting is the best alternative, he said.

For recruits in training at Fort Moore, Spencer said commanders have them practice an ice sheeting drill before most training events.

“A very good company would have trainees who will automatically grab the ice sheets and other trainees will start stripping the other trainee down … to his underwear,” Spencer said. “One ice sheet is placed in both armpits, one sheet in the crotch, one is placed around the neck, and placed on the [stretcher]. The casualty would be quickly placed on the [stretcher] and immediately we’d be dialing 911.”

DeGroot said commanders at Fort Moore’s Maneuver Center of Excellence, which oversees the installation’s initial entrance training, officer training, and Ranger and Airborne schools have bought into his instruction, leading to a lower number of serious heat injuries in recent years.

Army armor recruits at Fort Moore, Ga., practice arm immersion cooling June 29, 2023, during their Thunder Run as part of Armor One Station Unit Training. The practice is meant to prevent recruits from overheating on hot days. (Patrick A. Albright/U.S. Army)

Fort Moore has seen the highest rates of heat injuries among all the Defense Department’s installations worldwide for years, according to the Defense Health Agency.

From 2018 to 2022, Fort Moore accounted for some 16.7% of all U.S. military heat injuries with 2,075 during that time, according to DHA data. The next highest rate occurred at the Marines’ Camp Lejeune, N.C., with 936 reported heat injuries during that same time. Fort Liberty, N.C., formerly known as Fort Bragg, was just behind Camp Lejeune with 935 heat injuries. Fort Campbell, Ky., Fort Johnson, La., formerly Fort Polk, and Marine Corps Recruit Depot Parris Island, S.C., had the next highest rates, all with fewer than 750 heat injuries between 2018 and 2022, according to DHA.

While Fort Moore has consistently reported the most heat injuries each year, DeGroot said the severity of those heat injuries have fallen, especially since the Heat Center was activated on the post four years ago.

In 2018, 96 troopers suffered heatstroke, but the number of serious heat injuries has fallen consistently each year since 2018 to 35 last year. DeGroot said data for 2023 was not yet available, but it appeared to be on a similar pace to 2022.

DeGroot admitted the record-high heat this summer has him concerned. NASA said last month was the hottest June in Earth’s recorded history, and last week the European Union’s Copernicus Climate Change Service indicated July was set to be named the hottest month in world history.

The issue that is really concerning to DeGroot are instances when temperatures do not dip at least into the lower 70s at night.

“I'm pretty confident on what we've been doing with the training and education that [Army] leaders out there are making smart decisions,” he said. “There's a lot of fixation on the high temperatures of today, but we already do a really good job of avoiding the high-intensity training at the hardest times of the day. But, when we’re running into days when the coolest time of the day isn’t cool, then we're running into some challenges that get that much harder to mitigate.”

Army research, which has included DeGroot, has shown the vast majority of heat injuries occur during prolonged endurance activities, such as ruck marches and runs, especially when troops carry heavy loads.

About 80% of heatstroke incidents at Fort Moore between 2017 to 2021 occurred during foot marches or runs, according to a study published last month in the Journal of Applied Physiology. DeGroot was one of the authors on the report, titled “Beating the Heat: Military Training and Operations in the Era of Global Warming.”

DeGroot said it could become increasingly problematic for commanders if scheduling long movements with heavy weight during the summer months at night does not effectively mitigate heat injury because of high nighttime temperatures.

“If we’re doing foot marches at 4 a.m., and it’s still pretty warm, just practically speaking, that’s where I'm starting to get more concerned,” he said.

For Spencer, an infantry mortarman who served multiple combat tours in Iraq and Afghanistan before becoming a drill instructor, despite the increasing heat, the Army still must train its recruits to operate under extreme conditions.

“Soldiers have to adjust whether that’s cold or heat. You have to be prepared to fight where the Army needs you to fight — hot or cold,” he said. “So, the increased heat — it's not really worrying. It's just one of those things that we have to put it in our mind, and we need to keep it there as we continue working in the Army.”