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CHAPTER 2

INDIVIDUAL PREVENTIVE MEDICINE MEASURES

Section I. HEAT INJURIES

OVERVIEW

Heat injuries can occur anywhere, depending on physical activity (work rate) and clothing worn. However, they occur most frequently during warm-weather training, exposure to high climatic temperatures, high humidity, and bright sunlight. These conditions make it difficult for the body to regulate its temperature. Hot weather also increases daily water requirements, because body water is lost as sweat. Dehydration leads to added heat stress, increased susceptibility to heat injury, reduced work performance, and degraded mission capability.

ACCLIMATIZATION

When the mission permits, all personnel should work and exercise in a manner so that they gradually become acclimatized to the heat and humidity in the AO. Significant heat acclimatization requires at least 3 to 5 days and full acclimatization can take up to 2 weeks. Exercising in the heat and humidity for 1 to 2 hours daily, gradually increasing the workload each day, can produce acclimatization. (Refer to Table 3-1 in Chapter 3.) When the mission does not permit time for gradual increases in workload, then leaders and buddies must observe each other and ensure that everyone drinks plenty of water during each work period. Individuals leaving a cold or cool climate will require additional time to become acclimatized to a hot climate.

DRINK PLENTY OF WATER

Depending on the heat and activity level, you may need to drink from 1/2 to 11/4 quarts of water per houró3 gallons/12 liters per day in hot, dry climates. Drinking water is a must in order to prevent heat injury. If desired, individuals may add flavoring to the water to enhance consumption. Field rations/meal (s), ready to eat (MRE) have flavoring for water in each meal. It the flavoring is used, add it to water in your canteen cup. Do not add flavoring to the water in your canteen; it increases the risk of contamination and illness. Never flavor the bulk source water supply. (Flavoring the bulk source water supply will reduce the action of water disinfectants.) See Table 3-1 for water intake requirements.

Drink extra water before starting any mission or hard work. Cool water (60° to 70° Fahrenheit [F]) is absorbed faster than cold water.

Drink small quantities of cool fluids frequently. Carbohydrate/electrolyte beverages (sport drinks) may provide supplemental nutrients under conditions of extreme calorie and water requirements; such as extremely vigorous activity. However, they cannot replace and must not be used to meet all water requirements.

Drink non-caffeinated fluids even if you are not thirsty. (Caffeine increases water requirements in all environments.)

Refill your canteens at every opportunity, using only treated water, if possible.

NOTE

The color and volume of the urine steam are good indicators of a service member's hydration status. If your urine stream is dark yellow and the volume is small, or if you are constipated and experience hard stools, you may not be drinking enough water. Maintain a urine stream that is clear or light yellow. Thirst is not a good indicator of dehydration during physical activity.

USE WORK/REST CYCLES

Work and rest as your leader directs. (See Table 3-1.) A rest period helps prevent dangerous increases in body temperatures by minimizing heat production.

Work and rest in the shade, if possible.

EAT ALL MEALS TO REPLACE SALTS

Eating all meals in the field will usually provide the body's requirements for salts. Field rations/MRE meet the daily requirements for minerals and electrolytes (sodium). DO NOT take extra salt in meals unless medically indicated.

NOTE

DO NOT TAKE SALT TABLETS. One salt tablet increases your water requirement by at least a pint. Salt draws water from muscles to dilute your blood. Salt tablets can cause vomiting.

RECOGNIZE THE RISK OF MISSION-ORIENTED PROTECTIVE POSTURE/BODY ARMOR/ARMORED VEHICLES

 Mission-oriented protective posture (MOPP)/body armor increases your heat stress. (See Table 3-1.) You must  Drink more water. DO NOT EXCEED 11/4 QUARTS PER HOUR.

 Work and rest as your leader directs.

You may be at a greater risk of heat injuries when in armored vehicles you may need to drink more water.

MODIFY YOUR UNIFORM

When directed/authorized by your commander to reduce heat stress and to protect against ultraviolet (UV) radiation, you should

Unblouse pants from boots.

Cover all skin exposed to sun; wear sunscreen and lip balm with a sun protection factor of 15 or higher.

Protect the eyes from UV with UV-protective sunglasses, especially wraparound sunglasses.

Seek shade when resting outdoors.

Keep clothing loose at the neck, wrists, and lower legs.

NOTE

When the threat from biting arthropods is high, keep your shirtsleeves rolled down and pants bloused in boots.

NOTE

See Graphic Training Aid GTA 05-08-012 and FM 4-25.11, for information on heat injury prevention and first aid.