Heat Illness Prevention & Sun Safety

 Heat-Related Illness Prevention

Last Updated: November 27, 2023


Heat illnesses occur year round in training environments and increase significantly in warmer weather.

​What are heat illnesses? 

In the military, heat illnesses  are typically associated with warmer weather and physical activity so are referred to as Exertional Heat Illnesses (EHI), a range of conditions that can occur when the body overheats. EHI range from dehydration and mild heat cramps, to a more serious medical condition called heat exhaustion, to the life-threatening medical emergencies heat stroke and hyponatremia (a condition when excessive water consumption causes an imbalance to the body’s chemistry). Failure to prevent milder conditions from progressing can result in more serious heat casualties, including death.​ 

​News article: Service members need to remember signs, symptoms of heat illness as weather warmsExternal Link (Mar 2023)​

Risk factors for heat illness

Environment: high temperature, high humidity, wind, solar load, repeated hot/humid days

Mission: high exertion/intensity, heavy loads/gear, repeated strenuous days

Individual: acclimatization status, poor fitness (2 mile run >16 minutes for males, >19 minutes for females), BMI >26, age <20 or >40, poor hydration/nutrition status, minor illness (fever, skin rash, sunburn, or poison ivy), medication (antihistamines, decongestants, some blood pressure medications, some psychiatric drugs), alcohol use in the past 24 hours, sleep deprived, highly motivated

Heat Illness Prevention: What can you do?

See the Milita​​ry Health Illness Prevention Brochure (2023)

Service Members:

  • Ensure adequate sleep, hydration, and nutrition prior to training
  • ​Start hydrate and stay hydrated with regular intake of food and fluids
  • Avoid excessive hydration - under most training conditions, consume 1 quart/hour (for very strenuous conditions a maximum of 1.5 quarts/hour is advised)
  • Recognize early signs and symptoms of heat illness in yourself and fellow Service Members
  • Rehydrate slowly and steadily after training and replenish salts and nutrients via food intake


  • Use risk management guidelines when planning for training in the heat
  • Ensure personnel are trained on prevention, recognition, and basic treatment of heat illness
  • Plan for rapid cooling (arm immersion cooling stations, ice sheets) at training locations
  • Monitor the wet bulb globe temperature and adjust activity as needed
  • Encourage consistent food and fluid intake, but watch for excessive fluid intake
  • Know the current profile status of Soldiers
  • Soldiers with previous heat illness should be monitored closely for over-hydration and signs and symptoms of repeat heat illness


  • Initial management and most effective intervention in suspected heat illness is rapid cooling
  • Verify sodium level prior to and during rehydration efforts
  • Proper profiling per AR 40-501 will minimize recurrent heat illness in susceptible Soldiers
  • Notify preventive medicine to report cases of heat illness (heat exhaustion and heat stroke are reportable medical events and should be reported to the Disease Reporting System internet)