© 2010 McGraw-Hill Higher Education. All rights reserved. Chapter 9: Understanding the Potential Dangers of Adverse Environmental Conditions

© 2010 McGraw-Hill Higher Education. All rights reserved.

Chapter 9: Understanding the Potential Dangers of Adverse

Environmental Conditions


• Environmental stress can adversely impact an athlete’s performance and pose serious health threats

• Areas of concern– Hyperthermia– Hypothermia– Lightening storms– Over exposure to the sun


Hyperthermia• Athletic trainers require knowledge and

information concerning temperature, humidity and weather to adequately make decisions regarding environmental dangers

• Has caused a number of deaths over the years

• Must manage heat stress appropriately• Hyperthermia = increase in body temperature


• An individual does not have to be in the south to experience a heat-related illness

• Anyone that supervises athletes practicing and competing must realize that heat and humidity impact every geographic region of the United States

• Imperative to be able to recognize signs and symptoms associated with heat-related illnesses and to be able to manage them appropriately


Heat Stress• Extreme caution should be used when training in

the heat (overexposure could result heat stress)• It is preventable• Athletes that train under these extreme conditions

are at risk• Physiologically the body will continue to function if

body temperature is maintained• Body must dissipate heat to maintain homeostasis


• Heat can be dissipated from the body through 4 mechanisms– Conduction (direct contact)– Convection ( contact with cool air or water mass)– Radiation (heat generated from metabolism)– Evaporation (sweat evaporating from the skin)

• Majority of body heat is dissipated through evaporation

– * Heat can also be gained via these four mechanisms


• Evaporative Heat Loss– Sweat glands allow water transport to surface– Evaporation of water takes heat with it– When radiant heat and environment temperature are higher than

body temperature, loss of heat through evaporation is key– Lose 1 quart of water per hour for up to 2 hours– Air must be relatively water free for evaporation to occur

• relative humidity of 65% impairs evaporation• relative humidity of 75% stops evaporation

– Heat illness can still occur in cold environment if body is unable to dissipate heat

• Caused by dehydration and inability to sweat


Monitoring Heat Index

• Heat, sunshine and humidity must be monitored closely– Takes into account ambient air temperature and

relative humidity– Attempts to determine how hot it feels to the body

• Wet bulb globe temperature index (WBGT) provides objective measure for determining precautions concerning participation in hot



– WGBT incorporates different thermometer readings• Dry bulb (standard mercury temperature)

• Wet bulb (thermometer with wet gauze that is swung around in air)

• Black bulb (black casing that measures radiant heat)

• Formula yields WBGT index

– DBT and WBT can be measured with psychrometer (combines both thermometers)

• Wet bulb will be lower due to evaporation of water

• Drier air = greater depression of wet bulb temperature due to evaporation


– Ventilation is provided by whirling thermometer (sling psychrometer) or suction fan (aspiration psychrometer)

– Newer models utilize digital sensors



Heat Illnesses

• Heat Syncope (heat collapse)– Associated with rapid fatigue and

overexposure, standing in heat for long periods of time

– Caused by peripheral vasodilation, or pooling of blood in extremities resulting in dizziness and fainting

– Treat by placing athlete in cool environment, consuming fluids and laying down


• Exertional Heat Cramps– Painful muscle spasms (calf, abdominal) due to

excessive water loss and electrolyte imbalance– Occurs in individual in good shape that overexert

themselves– Treatment

• Prevent by consuming extra fluids and maintaining electrolyte balance

• Treat with fluid ingestion, light stretching with ice massage• Return to play unlikely due to continued cramping


• Exertional Heat Exhaustion– Result of inadequate fluid replacement– Will exhibit signs of profuse sweating, pale skin, mildly

elevated temperature, dizziness, hyperventilation and rapid pulse

– May develop heat cramps or become faint/dizzy– Core temperature will be ~102o

• Critical to obtain accurate core temperature

– Performance may decrease– Immediate treatment includes fluid ingestion (intravenous

replacement, ultimately), place in cool environment


• Exertional Heatstroke– Serious life-threatening condition, with unknown specific cause– Characterized by sudden onset - sudden collapse, LOC,

flushed hot skin, minimal sweating, shallow breathing, strong rapid pulse, and core temperature of > 104o F

– Temperature must be lowered within 45 min.– Drastic measures must be taken to cool athlete

• Strip clothing• Sponge with cool water• Do not immerse in water• Transport to hospital immediately


• Exertional Hyponatremia– Fluid/electrolyte disorder resulting in abnormally low

concentration of sodium in blood– Caused by ingesting too much fluid before, during and

after exercise– May be result of too little sodium in diet or in ingested

fluids over a period of prolonged exercise– Athletes that ingest large quantities of water and sweat

over several hours are at risk (marathon, triathlon)– Preventable – must maintain balance


Preventing Heat Illness• Must exercise common sense and precaution

– Consume fluids and stay cool

• Fluid and Electrolyte Replacement– Single most important step taken by a coach to

minimize the chance of heat illnesses– Continual re-hydration is critically important– Generally only 50% of fluid is ever replaced and

should therefore be replaced before, during and after exercise


– Fluid replacement should match sweat loss• Most effectively replaced at regular intervals (15 min.)

– Time of stomach emptying is critical• Water is absorbed rapidly from intestine• Drink with 6% CHO is eliminated at the same rate if the individual is

hydrated• Cold drinks tend to empty rapidly and will not induce cramping or put

heart at risk• Drinks with caffeine and alcohol will promote dehydration

– Hydration levels can be monitored via urine color and volume• Appropriate hydration = clear urine at normal or above-normal output

level 60 minutes following exercise


• Using Sports Drinks– More effective than just replacing fluids with water– Flavoring results in increased desire to consume– Replaces fluids and electrolytes– Water alone can prematurely stop thirst response and initiate fluid

removal by kidneys– Small amounts of sodium help in retention of water– Different drinks have different nutrient levels– Optimal CHO level is 14g per 8 ounces of water– More CHO results in slower absorption– Effective for both short term and endurance activities


• Gradual Acclimatization– Most effective method of avoiding heat stress– Involves becoming accustomed to heat and

exercising in heat– Early pre-season training and graded intensity

changes are recommended with progressive exposure over 7-10 day period

– 80% of acclimatization can be achieved during first 5-6 days with 2 hour morning and afternoon practice sessions


• Identifying Susceptible Individuals– Athletes with large muscle mass– Overweight athletes are at an increased risk

• Related to proportionality of metabolic heat production to surface area

– Athlete with increased fluid loss– While slight differences exist, precautionary measures apply to

both males and females– Athletes consuming medications or supplements may have

impaired sweating and may predispose them to injury– Athletes with poor fitness levels, a history of heat-related

illnesses or anyone with febrile conditions are at increased risk


• Uniform Selection– Base on temperature and humidity– Dress for the weather and temperature– Avoid rubberized suits

• Weight Records– Keep track of before and after measures for first two weeks– If increase in temperature and humidity occurs during the

season, weights should again be recorded– A loss of 3-5% = reduced blood volume and could be a

health threat


Hypothermia

• Cold weather vs. nature of particular sport• Most activity allows for adequate heat

production (increased metabolism) and dissipation, allowing for sufficient functioning

• Impact on warm-up and “down time”• Temperature in conjunction with wind chill

and dampness or wetness can increase chances of hypothermia


• With muscular fatigue, in cold weather, rate of exercise begins to drop and rate of heat loss relative to heat production may shift – Results in impaired neuromuscular responses and

exhaustion

• Drop in core stimulates shivering but stops after temp. drops below 85-90oF

• Death is imminent when temp falls below 77-85oF.


Cold Disorders• Fluid replacement is critical even under colder

environmental conditions– Dehydration = decreased blood volume = less fluid

available for tissue warming

• May be useful to monitor weight of athletes training in cold temperatures

• While less common, injury/illness due to the cold still occur, particularly in endurance type activities, winter sports and swimming in cold water


• Frost nip– Involves, ears, nose, chin, fingers, and toes– Occurs with high wind and/or severe cold– Skin appears firm with cold painless areas

that may peel and blister (24-72 hours)– Treat with firm pressure, blowing warm air

or hands in armpits (if fingers involved)– Do not rub


• Frostbite– Superficial Frostbite involves only skin and

subcutaneous tissue• Appears pale, hard, cold and waxy• When re-warming the area will feel numb, then sting and burn• It may blister and be painful for several weeks

– Deep Frostbite indicates frozen skin requiring hospitalization

• Rapid re-warming is necessary (100-110oF)• Tissue will become blotchy red, swollen, painful and may

become gangrenous



• Prevention– Apparel geared for weather to provide semitropical

microclimate for body and prevent chilling– Waterproof and windproof fabrics that allow

passage of heat and sweat and allow movement– Layers and adjusting them are key to maintaining

body temperature (during period of (in)activity)– Inadequate clothing, improper warm-up and chill

factor can lead to injury, frostbite, and/or minor respiratory problems


Overexposure to Sun• Precautions must be taken to protect athletes,

coaches, athletic trainers and support staff• Long Term Effects on Skin

– Premature aging and skin cancer due to ultraviolet exposure

– Premature aging is characterized by dryness, cracking and inelasticity of the skin

– Skin cancer is the most common malignant tumor found in humans


• Using Sunscreen– Can help prevent damaging effects of UV radiation– Sunscreen effectiveness is expressed as SPF (sun

protection factor)• Indicates how many times longer an individual can be exposed

to the sun with vs. without sunscreen before skin turns red.• Greater the susceptibility the higher the SPF should be used

– Should be worn by athletes, coaches and athletic trainers who are outside a considerable amount, and/or have fair complexion, light hair, blue eyes or skin that burns easily


– Sunscreen use is at its highest March - November but should be used year round (particularly between the hours of 10am-4pm)

– It should be applied 15-30 minutes before exposure and re-applied after exposure to water, excess sweating, rubbing skin with clothing or a towel


Safety in Lightening and Thunderstorms

• #2 cause of death by weather phenomena

• NATA has established position statement due to number of athletes and coaches potentially exposed to lightening scenarios

• Emergency action plans must be set for this type of event – Involving chain of command, monitoring of weather

service, decision making regarding removal and return to field


• In the event of a storm, shelter indoors should be obtained

• Other guidelines– Avoid large trees, flag/light poles, standing water,

telephones, pools, showers, and metal objects (bleachers, equipment, umbrellas)

– Last resorts find car, ravine, ditch or valley for safety– If hair stands up on hand you are in imminent danger

and should get down on the ground but not flat as that increases surface area


• Additional Guidelines– Lightening is generally accompanied by thunder

(except 20-40% of the time due to atmospheric disturbances)

– Flash-to-bang methods estimates distance away for the storm

• From time lightening is sighted to the clap of thunder count, divide by 5 to calculate the number of mile away

• Count of 30 indicates inherent danger• Count of 15 seconds everyone should leave the field


– NATA and National Weather Service recommend returning to the field 30 minutes following the last clap of thunder or lightening strike

– Major misconception is that lightening that is seen striking is coming down

• In actuality it is the return stroke of the lightening going back up after it has already hit the ground


• Lightening Detectors– Hand-held instrument with

electronic system to detect presence and distance of lightening/thunderstorm activity (w/in 40 miles)

– Can determine level of activity and direction of movement

– Provides audible and visual warning signals

– Inexpensive alternative to contracting weather services

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© 2010 McGraw-Hill Higher Education. All rights reserved. Chapter 9: Understanding the Potential Dangers of Adverse Environmental Conditions