Plan for the heat to eliminate illness

With summer fast approaching, leaders and Soldiers should be considering hot weather hazards. Heat illnesses, including heat exhaustion and heat stroke, degrade mission effectiveness and can happen during any month, but most occur between June and July.

The Army Public Health Center reported 1,423 heat illness cases (1,229 heat exhaustion and 194 heat stroke) in 2020 and 2,095 heat illness cases (1,695 heat exhaustion and 400 heat stroke) in 2019. The COVID-19 pandemic and limitations on activities and training in 2020 probably account for some of the decrease in heat illness cases. Leaders at all levels must be familiar with the principles of risk management to properly identify and mitigate operational hazards, including environmental conditions.

Key to this task is ensuring Soldiers and subordinate leaders know the methods for preventing heat illness, use the risk management process to mitigate hazards associated with working and training in the heat, and have and rehearse a detailed plan for responding to individuals suffering from heat illness. The first step in mitigating the risk of training and working in the heat is to understand the underlying hazards. Leaders should evaluate environmental factors including temperature, humidity, wind, solar load and the number of days with high heat and humidity. They should also evaluate each task for required intensity level and exertion, load to be carried, and total days of repeated strenuous activity. Individual Soldier factors matter as well, including acclimatization to heat and humidity, fitness level, age (younger than 20 or older than 40), nutrition and hydration status and underlying minor illnesses (fever, colds, nausea or vomiting). Prescribed or over-the-counter medications and supplements, hours of sleep, alcohol use, history of prior heat illness, skin disorders preventing effective sweating (heat rash and sunburn), body mass index (overweight or obese) and motivation to complete the mission or task are also factors.

In the absence of other risk factors, highly motivated Soldiers can be at increased risk of becoming a heat casualty. The next step is to implement controls that decrease the risk of heat illness. Leaders must monitor and record the Wet Bulb Globe Temperature and adjust work/rest cycles based on work intensity. One example control is rescheduling events to times with cooler temperatures and decreased humidity. In addition, leaders should schedule time for their Soldiers to acclimate to hot and humid weather. Acclimation generally requires 10 to 14 days of moderate to vigorous aerobic activity; physically fit Soldiers acclimate faster. It also increases sweating, so proper hydration and nutrition are paramount to preventing heat illness. Soldiers should not skip meals or overhydrate, which can cause hyponatremia (low sodium), a serious illness. One quart of water per hour is sufficient under most conditions, but Soldiers should never exceed 1.5 quarts per hour with very strenuous work or 12 quarts per day. The APHC’s Work/Rest Times and Fluid Replacement Guide is an excellent resource at

Most of all, leaders must know their Soldiers. Those with previous heat illness require careful monitoring, and all Soldiers must be watched for symptoms of heat injury. Common signs include dizziness, headache, nausea, unsteady gait, weakness or fatigue and muscle cramps. More symptoms that are serious include vomiting, involuntary bowel movement, convulsions, hyperventilating, rapid or weak pulse and unresponsiveness or coma. Heat exhaustion and heat stroke require rapid recognition, treatment and evacuation to definitive medical care, and the response plan must be understood and rehearsed by all leaders and Soldiers. Rapid cooling, whether from ice sheets or cold-water immersion stations, should be part of the plan. Soldiers with symptoms of heat illness should be placed in the shade with their clothing and boots loosened. If conscious, a heat casualty may receive small sips of water not to exceed 1 liter. Suspected heat stroke (confusion or other signs of altered mental status) is a life-threatening medical emergency and requires rapid cooling and evacuation to definitive medical care. Never prolong initial treatment in the field — immediately call 911 or follow the request for evacuation procedures in a field environment.

All Soldiers with suspected heat illness must be evacuated for evaluation and treatment by medical personnel. Leaders must ensure all heat illnesses treated beyond first aid are reported via the Army Safety Management Information System 2.0 at Army Regulation 385-10, The Army Safety Program, defines first aid.

By Col. Eric Olins

Command Surgeon U.S. Army Combat Readiness Center