Transcript Document 7198311

Chapter 10:
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
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Heat Illness
Overexposure to the sun
Cold Illness
Lightening storms
Role of Water in the
Body
Hyperthermia
 Athletic trainers require
knowledge and information
concerning temperature,
humidity and weather to
adequately make decisions
regarding environmental
dangers
 Hyperthermia = increase in
body temperature
 Has caused a number of deaths
over the years
 Must manage heat stress
appropriately
Heat Stress
 Extreme caution should be used when
training in the heat (overexposure could
result in heat stress)
 It is preventable
 Athletes who 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 environmental
temperature are higher than body
temperature, loss of heat through
evaporation is key
Evaporative Heat Loss
 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
 Wet bulb globe temperature index (WBGT)
provides objective measure for
determining precautions concerning
participation in heat
 WBGT 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 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
Heat Cramps
 Painful muscle spasms (calf,
abdominal) due to excessive water
loss and electrolyte imbalance
 Occurs in individuals in good shape
who 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
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 ~102oF
 Performance may decrease
 Immediate treatment includes fluid ingestion
(intravenous replacement, ultimately), place in
cool environment
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 minutes
 Drastic measures must be taken to cool athlete
 Strip clothing
 Sponge with cool water
 Ice or cold water immersion is best known treatment for
rapid cooling
 Transport to hospital immediately
Preventing Heat Illness
 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
 Fluid replacement should match sweat loss
 Most effectively replaced at regular intervals (15 minutes)
 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 abovenormal output level 60 minutes following exercise
Using Sports Drinks
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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
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Athletes with large muscle mass
Overweight athletes
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
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% normal body mass =
reduced blood volume and could be
a health threat
Overexposure to Sun
 Precautions must be taken to
protect athletes, coaches,
athletic trainers
 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
 The greater the susceptibility, the higher the
SPF that 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
Using Sunscreen
 Sunscreen use is at
its highest March November but should
be used year round
(particularly between
the hours of 10am4pm)
 It should be applied
15-30 minutes before
exposure and reapplied after exposure
to water, excess
sweating, rubbing
skin with clothing or a
towel
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
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 (100110oF)
 Tissue will become blotchy red,
swollen, painful and may become
gangrenous
Phases of Frostbite
Prevention of Cold Illness
 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
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
Guidelines for Safety
 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
Guidelines for Safety
 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 miles away
 Count of 30 indicates inherent danger
 Count of 15 seconds everyone should
leave the field
Guidelines for Safety
 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