Heat Illness Prevention & Sun Safety

Last Updated: February 10, 2025
Skip Navigation LinksDCPH-A Home / Topics / Diseases & Conditions / Heat Illness Prevention & Sun Safety
Soldier in desert

​​​Heat illness is particularly a concern for those who work outside and are at greater risk of heat related illness and injury since average temperatures have been notably high the last two decades (see article).​​

External Link 

Military personnel are at high risk for heat illness, because of the added heat stress from the body during vigorous activity. Therefore, military heat-related medical conditions are referred to as ‘exertional heat illness’ or EHI.​

EHI can range from mild to severe or even fatal conditions that occur when the body overheats. Though Service members may be relatively young and healthy, hundreds of military EHI or ‘heat casualties’, including 1 to 3 deaths, occur each year. 

! ALER​T !

  • Failure to prevent milder EHI from progressing can result in more serious heat casualties, including death. 
  • ​After experiencing a heat illness, a person is more prone to experiencing a future heat illness, including one that may be more severe than the first. 

New and Popular


Frequently Asked Questions

What are EHI conditions?

  • Milder conditions 
    • Dehydration 
    • Heat cramps
  • More serious conditions that can lead to permanent damage or be life-threatening: 
    • ​Heat exhaustion (a military Reportable Medi​​cal Event​), whe​n core body temperature has become elevated but remains below 104⁰F, observed sign/symptoms including dizziness, headache, nausea, weakness, unsteady gait, muscle cramps, fatigue can resolve rapidly with immediate cooling interventions (moving to shade, loosening uniform/removing head gear, encouraging drinking but track volume (no more than 1.5 quarts of water over 1 hour). Rapid intervention is necessary to prevent progression to heat stroke – casualty should be evacuated for further monitoring. 
    • ​​Heat stroke (a military Reportable Medi​​cal Ev​​ent​),​ is a life-threatening medical emergency when the core body temperature reaches ​104⁰F​​ or higher, and ​​is most often observed by a change in mental status (confusion, delirium, combative, loss of consciousness), there may be vomiting, weakness, convulsions and chills. Call EMS or for MEDE​VAC and remove all outer clothing and initiate rapid cooling with ice sheets - the faster the body is cooled, the less damage to the brain and organs.​​
      • Cover all but the face with ice sheets
      • Ensure the ice sheet is soaked prior to applying to the casualty
      • Switch ice sheets every 6 minutes with new ice sheets
      • Evacuate immediately 
    • ​​Hyponatremia, also a life-threatening medical emergency, is a condition that occurs when too much water has been consumed resulting in a dangerous imbalance to the body’s chemistry. Like heat stroke, mental status changes may be noted and there may be repeated vomiting (clear vomit). Additional signs may include distended/bloated abdomen and large amounts of clear urine. 
      • It is important to differentiate from heat stroke so determine if a casualty has consumed excessive water or fluids and or had poor food intake.  
      • Verify hydration and sodium intake and Call EMS or for M​EDEVAC 
      • Do NOT give more water or IV fluids
      • If awake, allow casualty to consume salty foods
      • Evacuate immediately 

​

What are risk factors for EHI? 

In addition to environmental factors, strenuous activity duration and frequency and individual factors impact a person's risk of developing a heat illness: 

  • High heat is a primary EHI hazard, so most EHIs occur between May and September, especially when the outside temperature is over 75° Fahrenheit (F). In addition to the temperature, sunlight, humidity, and wind speed all affect heat illness risk. 
  • ​Individual factors that increase susceptibility to heat illness include:
    • Having a heat illness one time (heat cramps, heat exhaustion, heat stroke) . 
    • Certain health conditions  
    • Poor fitness level (low aerobic fitness, and/or excessive weight) 
    • Certain medications
    • Poor nutrition and inadequate hydration 

What are the heat illness impacts to military readiness?

Heat illness, and dehydration from vigorous activity in heat, is a threat to individual health and to military operational success. Some supporting facts: 

  • Since 2014, more than 1,500 Soldiers each year have developed a heat illness that required medical attention and/or lost duty time (Army data).
  • Heat illnesses were responsible for more than 20,500 lost/limited duty days in 2017. 
  • Losing as much as 4% of body weight from dehydration can degrade physical performance. 
  • Every 1% loss of body weight increases core temperature (0.10-0.23⁰C or 0.18-0.40⁰F), thereby increasing risk of a more serious heat illness.

​

​