Heat Injuries

NOTE

In addition to the specific measures that follow, leaders must remember and apply the principle that the most effective PMM they can apply is to visibly set the example in the use of all the individual PMM that are discussed throughout this FM.

PLAN FOR THE HEAT

• Maximize physical fitness and heat acclimatization before deployment.

• Use your FST to train individuals and their leaders in PMM against heat.

• Acclimatize personnel to high temperatures as gradually as the mission will allow.

• Brief service members on dangers of sunburn and skin rashes and the importance of good personal field hygiene.

• Obtain weather forecast for time/area of training/mission.

• Ensure adequate supplies of potable water are available (up to 3 gallons per day per service member just for drinking) (See Table 3-1). Issue a second canteen to service members in hot weather operations. In the desert, additional canteens may be required.

• Know the location of water distribution points.

• Set up a buddy system to maximize rehydration and minimize heat injuries.

• Ensure medical support is available for treatment of heat injuries.

• Plan the placement of leaders to observe for and react to heat injuries in dispersed training (road marches), or operational missions.

• If the mission permits, plan to—
  • Train during the cooler morning hours.

  • Serve heavy meals in the evening, rather than at noon.

OBTAIN AND USE HEAT CONDITION INFORMATION

• Obtain heat condition information per your unit’s SOP or contact the local supporting PVNTMED detachment or section. Heat condition may be reported as -
  • Category: 1, 2, 3, 4, and/or 5.

  • Wet bulb globe temperature (WBGT) index.

• Use heat condition information to determine required water intake and work/rest cycles (Table 3-1).

NOTE

Training by lecture or demonstration, maintenance procedures on equipment, or personal hygiene activities (such as skin and foot care) can be performed during rest periods.

Table 3-1. Fluid Replacement Guidelines for Warm Weather Training (Applies to Average Acclimated Service Member Wearing Hot Weather Uniform)

HEAT CATEGORY WBGT INDEX DEGREES F EASY WORK MODERATE WORK HARD WORK WORK / REST MIN WATER INTAKE QT/HR WORK / REST MIN WATER INTAKE QT/HR WORK / REST MIN WATER INTAKE QT/HR 1 78-81.9 NL 1/2 NL 3/4 40/20 3/4 2 (GREEN) 82-84.9 NL 1/2 50/10 3/4 30/30 1 3 (YELLOW) 85-87.9 NL 3/4 40/20 3/4 30/30 1 4 (RED) 88-89.9 NL 3/4 30/30 3/4 20/40 1 5 (BLACK) > 90 50/10 1 20/40 1 10/50 1

The work/rest times and fluid replacement volumes will sustain performance and hydration for at least 4 hours of work in the specified heat category. Individual water needs will vary ± 1/4 quart/hour. NL= no limit to work time per hour. Rest means minimal physical activity (sitting or standing) accomplished in shade, if possible. CAUTION: Hourly fluid intake should not exceed 1 1/4 quarts. Daily fluid intake should not exceed 12 liters. Wearing body armor adds 5°F to WBGT Index. Wearing all MOPP overgarments adds 10°F to WBGT Index.

EASY WORK MODERATE WORK HARD WORK WEAPON MAINTENANCE WALKING HARD SURFACE AT 2.5 MPH, < 30 LB LOAD GUARD DUTY MARKSMANSHIP TRAINING DRILL AND CEREMONY WALKING LOOSE SAND AT 2.5 MPH, NO LOAD WALKING HARD SURFACE AT 3.5 MPH, < 40 LB LOAD CALISTHENICS PATROLLING INDIVIDUAL MOVEMENT TECHNIQUES, SUCH AS LOW CRAWL, HIGH CRAWL DEFENSIVE POSITION CONSTRUCTION WALKING HARD SURFACE AT 3.5 MPH, > 40 LB LOAD WALKING ON LOOSE SAND AT 2.5 MPH WITH LOAD FIELD ASSAULTS WARNING Hourly fluid intake should not exceed 1 1/4 quarts. Daily fluid intake should not exceed 12 liters.

ENFORCE INDIVIDUAL PREVENTIVE MEDICINE MEASURES

Leaders must—

• Enforce water intake by—
  • Observing service members drinking required amounts. Encourage frequent drinking of water in small amounts.

  • Ensuring that service members practice good field hygiene.

  • Providing cool water; if desired, you can add flavoring after disinfection to enhance consumption. Personnel should use their canteen cup for consumption of flavored water. DO NOT add flavoring to canteen water; use only plain water in canteen.

  • Ensuring troops drink water before starting any hard work or mission (in the morning, with/after meals).

  • Ensuring buddy system is being used.

  • Frequently checking service members’ canteens for water; not beverages.

  • Making sure service members have adequate time to eat and drink as mission permits. Permit personnel to consume carbohydrate/electrolyte beverages (sports drinks) as supplemental nutrients under conditions of extreme calorie and water requirements; such as extremely vigorous activities.

• Reduce heat injuries by—
  • Enforcing work/rest cycles when the mission permits. Permitting personnel to work/rest in the shade, if possible.

  • Encouraging service members to eat all meals for needed salts.

  • Adjusting workload to size of individuals, when possible.

  • Be prepared for heat casualties and decreased performance when water and work/rest cycle recommendations cannot be met.

MODIFY WEAR OF THE UNIFORM

Direct/authorize service members to—

• Keep skin covered while in sun.

• Keep uniform loose at neck, wrists, and lower legs (unblouse pants).

NOTE

If the medical threat from biting arthropods is high, keep sleeves rolled down and pants bloused in boots.

IDENTIFY SPECIAL CONSIDERATIONS

Identify and modify training/physical activity for service members with high-risk conditions of heat injuries, such as—

• Diseases/injuries, especially fevers, vomiting, diarrhea, heat rash, or sunburn.

• Use of alcohol within the last 24 hours.

• Overweight/unfit.

• Over 40 years old.

• Fatigue/lack of sleep.

• Taking medication (especially for high blood pressure, colds, or diarrhea).

• Previous heatstroke/severe heat exhaustion.

• Lack of recent experience in a hot environment.