Articles, Blog

Prevent Heat Illness in Training and Combat

February 9, 2020

Soldiers routinely performed strenuous
physical activity for training or job duties often warm or hot environments
and while wearing uniforms and carrying equipment. These conditions can lead to exertional
heat illness or EHI. In the past decade, on average two to three soldiers died and
more than one thousand soldiers lost duty time or were treated for non-fatal
EHI each year. Even mild EHIs degrade performance and increase risk of future
heat illness. Most EHIs are predictable and preventable. None should be fatal. You can help reduce
EHIs by being familiar with the conditions, risk factors and ways to
prevent them. EHI is a spectrum of mild to potentially
fatal conditions. If dehydration and mild EHI are caught early, severe EHI and
deaths can be prevented. Key types of EHIs include heat cramps
to heat exhaustion and heatstroke. Heat cramps are thought to be associated with
electrolyte imbalances and/or dehydration. Symptoms include muscle cramps, pain,
and spasms usually in the arms, legs or abdomen. If you experience heat cramps, stop your
activity and seek shade to prevent more serious EHI. Heat exhaustion occurs when
the body cannot keep up with the high blood flow needed for strenuous activity
and sweating in the heat. Symptoms can include headache, dizziness,
nausea and muscle cramps. By catching and addressing these symptoms early, more
severe EHI can be prevented. Heat injury and heat stroke are the most
severe forms of EHI and occur when the body’s cooling mechanism fails and can
no longer manage heat. A heat injury means there has been damage to organs like the
liver and kidney and muscle tissue. Without cooling or other intervention
this progresses to heat stroke when organ damage becomes more severe and affects
the central nervous system. A change in mental status is the hallmark of this EHI.
Other symptoms can include convulsions, vomiting, confusion and unconsciousness. If these symptoms occur, rapid, aggressive
cooling and evacuation for immediate medical treatment is essential to
prevent death. Another medical emergency that is
associated with the EHI is hyponatremia or water intoxication. Hyponatremia occurs when someone drinks
too much water in an effort to stay hydrated and causes an imbalance in the
body’s electrolytes. Symptoms may include vomiting and
confusion and can be fatal if not identified and treated immediately. It is important to monitor water
consumption to distinguish hyponatremia from other EHIs. Regardless of severity, all EHIs
require medical attention once signs and symptoms are identified. Consult Army
guidance for more information on treating these EHIs. The typical heat illness casualty in the
Army is a male between 18 and 24 years old with less than one year of service.
While anyone can develop an EHI, certain groups at greater risk include personnel
who: have had a prior heat illness, start a new strenuous training regimen in
warmer weather, especially those arriving from colder climates. Other key
individual risk factors to be aware of include hydration level, poor fitness, illness, alcohol use in the
past 24 hours, certain medications, high motivation. Most EHIs occur between May and September mostly when temperatures exceed 75 degrees Fahrenheit but Army data show that EHI including stroke occur
on cooler days throughout the year. In addition, overall heat exposure over
the past three days is more likely to influence the occurrence of EHIs.
Heat alone is not the only environmental factor that affects risk. The acronym
HEAT is often used to highlight the four key variables: Heat category, Exertion
levels, Acclimation, Time of exposure and rest period. There are several things you can do to prevent EHIs. Use the wet bulb globe temperature index
to adjust workload. Heat conditions are not adequately represented by the
outside temperature alone. Temperature, sunlight, humidity and wind
speed all affect the heat load on the body. The Army uses the WBGT index to combine
these four items to calculate risk categories. The five WGBT categories are used
to determine the recommended intensity of the day’s work load or type
of physical training activity at a specific location. For example, when the
WBGT reaches 82 degrees Fahrenheit, limit high-intensity workloads. The most important categories to watch
out for include categories four and five. Strenuous outdoor activities should be
avoided during category four and five conditions, especially on consecutive
days. Ways to modify activities include: conducting physical activities like road
marches or runs at dusk, night or before sun up; moving the location of physical
activities to shadier areas off paved roads or indoors; delaying the activities
to a later date. Ensure soldiers acclimate to warmer
climates and higher workloads. Personnel need time for their bodies to adjust to
warmer climates and increased activity levels in order to more efficiently
balance water and salt loss. Exposure to warmer weather and higher levels of
exertion should be gradual and allow adequate rest periods. The amount of time
needed to best acclimate depends on several factors and can range from a
week to a month. Consult Army guidance to identify the
amounts of time. Limit or modify physically demanding activities. Risk
for EHI increases when strenuous PT, sports or job tasks are performed over
long periods of time or over multiple days. Reduce activity length, frequency,
intensity and the amount of gear used accordingly. Remember: risk is even higher when
soldiers wear protective equipment or carry heavy loads. High-risk activities
include basic combat training, field training exercises and road marches over
eight kilometers. Add five degrees Fahrenheit to the WBGT
when wearing rucksacks or body armor. Add 10 degrees Fahrenheit for full chemical
protective gear. Monitor hydration status. Even in moderate weather soldiers can
become dehydrated if fluid levels are depleted from sweating during strenuous
activity. Dehydration strains the body and affects the soldier’s health and
physical performance and can lead to more serious EHI. Just a two percent
loss of body weight from dehydration may reduce performance. To prevent
excessive fluid loss, follow work/rest and water consumption
guidance and track individual fluid intake by wearing knots or beads on outer
garments and use urine color charts. Prevention of EHI starts with
awareness of risk factors and early detection of symptoms to prevent more
serious illness. Use the buddy system to monitor hydration status and keep
everyone safe. For more information on heat illness,
check out these resources available on the APHC website.

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