Heat Illness and Sun
Damage Prevention: What can you do?
1. Know the primary risk factors:
- Environmental Factors:
- High temperature, high humidity, wind – know the Wet Bulb Globe Temperature (WBGT) risk category*
- Sun/UV time and intensity
- Repeated hot/humid days (more days in a row = higher risk)
*NOTE:
The WBGT is used by the military to determine “Flag Day" levels of risk by installations.
Some installations are at higher risk than others due to routinely high WGBT,
but – - WBGT is required by military doctrine to be taken throughout the day at specific times and locations of an outdoor military activity to assess risk. This is because WGBT varies throughout the day AND can vary substantially at different locations on an installation.
- The amount of time exposed and number of consecutive days of strenuous activities in high heat increases the risk of an EHI.
- Mission Factors:
- High exertion/intensity activity for duration (e.g. ruck marching)
- Heavy loads/gear (rucks, armor, weapons)
- Repeated (consecutive >2 strenuous activity days)
- Individual Factors:
- Acclimatization status (higher risk if not used to heat/activity >2 weeks)
- Poor fitness (slow or not passing run times, high weight/body mass index)
- 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 (can overexert body, surpassing physiological limits)
2. Take Actions
PROVIDERS:
- Review medical history and document heat-related conditions – proper profiling can minimize recurrent heat illness in susceptible personnel.
- Ensure cases of heat illness (heat exhaustion and heat stroke are RMEs) are reported to the Disease Reporting System internet (AR 40-501).
LEADERS:
Use the WBGT Index to determine Operational Risk Management (ORM) steps:
- Identify the hazards
- Know the WBGT
- Know the risk factors for heat illness
- Assess hazards
- Use the WBGT index to plan training activities
- Factor in training event, uniform/equipment requirements, location and time of day
- Know the acclimatization and profile status of your personnel
- Factor in previous days' condition, activities, and recovery time
- Develop controls
- Estimate heat Risk Category and follow appropriate work/rest guidance
- Establish heat illness procedures and training for leadership and all personnel
- Prepare water, medical, and evacuation support
- Implement controls
- Adjust activity distance, duration, time, pace, and/or load
- Provide water and/or electrolyte drink
- Avoid back-to-back strenuous days in the heat
- Supervise and evaluate
Use ORM when planning for training in the heat:
- Monitor WBGT and adjust outdoor activity levels, duration, location and time of day as needed
- Find ways to reduce heat stress in individuals:
- Conduct training and other strenuous activities in the early morning or evening when possible.
- Plan for rapid cooling (Arm Immersion Cooling System (AICS) stations, ice sheets) at training locations
- Encourage consistent food and fluid intake, but watch for excessive fluid intake
- Ensure personnel are trained on heat illness prevention, recognition, and basic treatment
- Know the current profile status of service members – those with previous heat illness should be monitored closely for over-hydration and signs and symptoms of repeat heat illness.
SERVICE MEMBERS:
See the Military Health Illness Prevention Brochure (2023)
- Know the heat category (WBGT) at your location and be aware as it changes over time
- Wear clothing level appropriate for the Risk Category
- Stay hydrated but avoid over-hydration
- Adhere to fluid replacement and work-rest guidelines
- Do not exceed 1 quart per hour (qt/h) under most conditions
- Under certain very strenuous conditions a maximum of 1½ qts/h or 12 qts/day may be advised
- As a means of self-check, urine should in general be pale yellow to clear (this is not always a guarantee, however, as individual conditions may affect color)
- Do not empty canteens to lighten your load
- Avoid use of alcohol, energy drinks, and supplements
- Salt tablets are not recommended
- Flavored drink powders can be used to encourage fluid consumption
- Know your limits – don't ignore signs and symptoms (yourself and your buddy). Data shows that military personnel in competitive training environments have high rates of heat illness.
- Inform your leader and battle buddy if you have had a prior EHI or have specific EHI risk factors.
- Use beads or knots to track how much fluid you are consuming (allowing others to see your fluid consumption can be lifesaving and may be the only immediate way to differentiate heat stroke and hyponatremia.
- Reduce exposure to UV rays:
- Off duty/General
- Never use tanning beds
- Minimize exposure to intense outdoor UV radiation by exercising indoors or exercising in the early morning or late evening
- Wear clothing as a barrier to skin exposed to sunlight
- Wear hats (ideally wide-brimmed)
- Wear sunglasses
- Regularly apply sunscreen to exposed areas such as your face, neck, hands, and arms with SPF 30 or higher. Apply liberally (minimum of 1 oz) approximately 30 minutes before sun exposure and at least every 2 hours or after the skin has been wet.
- Additional tips when on duty:
- Apply sunscreen first, approximately 30 minutes prior to applying DEET skin repellent. Reapply sunscreen throughout the day.
- Seek shade as much as possible. Work and rest in the shade when possible. Construct shades (tents) if necessary. The sun's rays are strongest between 1000 and 1600 hours. Try to avoid being in the sun during these times.
Use clothing as a protective barrier. Wear a wide-brimmed hat to protect your eyes, head and neck. The military authorizes use of a wide-brimmed hat (e.g., military boonie hat), including during PT and training. Wear light-colored, loose-fitting clothing to cover your arms, legs and torso.
- Protect eyes from snow blindness and other eye damage. Military personnel should generally consider wraparound design eyewear or goggles if possible. In addition, polarized lenses help reduce exposure from snow, water, sand, and other reflective surfaces. Choose sunglasses that provide 99-100 percent protection from UVA and UVB, or marked as having a UV400 rating. Military Combat Eye Protection (APEL) items block 100 percent of UVA and UVB rays, and include wraparound selections.
