Transcript Chapter 6: Environmental Conditions

Chapter 6: Environmental
Conditions
• Environmental stress can adversely impact
an athlete’s performance and pose serious
health threats
• Areas of concern
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Hyperthermia
Hypothermia
Altitude
Exposure to the sun
Lightening storms
Air pollution
Circadian dysrhythmia
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
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 be dissipate heat to maintain
homeostasis
• Metabolic Heat Production
– Normal metabolic function results in
production of heat (will increase with intensity
of exercise)
• Conductive Heat Exchange
– Physical contact with objects resulting in heat
loss or gain
• Convective Heat Exchange
– Body heat can be lost or gained depending on
circulation of medium
• Radiant Heat Exchange
– Comes from sunshine and will cause increase in
temperature
• Evaporative Heat Loss
– Sweat glands allow water transported 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 relative water free for evaporation
to occur
• relative humidity of 65% impairs evaporation
• relative humidity of 75% stops evaporation
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 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 rash (prickly heat)
– Benign condition associated with red, raised
rash, combined with prickling with sweat
– Result of continuously wet un-evaporated sweat
– Continually toweling the body will prevent
– Generally localized to areas covered with
clothing
• 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 individual in good shape that
overexert themselves
– 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 ~102o
– 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 > 106o F
– Temperature must be lowered within 45
minutes
– Drastic measures must be taken to cool athlete
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Strip clothing
Sponge with cool water
Do not immerse in water
Transport to hospital immediately
– Malignant hyperthermia
• muscle disorder causing hypersensitivity to
anesthesia and heat
• Similar S&S to heatstroke - muscle biopsy is needed
to detect
• Athlete with condition should be disqualified from
competition in hot, humid environments
• Acute Exertional Rhabdomyolysis
– Sudden catabolic destruction and degeneration of
skeletal muscle (myoglobin and enzyme leakage
into vascular system)
– Occurs during intense exercise in heat and
humidity resulting in:
• gradual muscle weakness, swelling, pain, dark urine,
renal dysfunction
• severe case = sudden collapse, renal failure and death
– Associated with individuals that have sickle cell
trait
– Should be referred to a physician immediately
Preventing Heat Illness
• Common sense and precaution
– Consume fluids and stay cool
• Fluid and Electrolyte Replacement
– Body requires 2.5L of water daily when
engaged in minimal activity
– 1-2% drop in body weight (due to dehydration)
results in thirst
– If thirst is ignored, dehydration results in:
• nausea, vomiting, fainting and increased risk for
heat illness
– More likely to occur when exercising outdoors
sweating heavily and engaging in strenuous
exercise
– Prevent through hydration, don’t ignore thirst,
and don’t rely on it being your indicator
– Generally only 50% of fluid is ever replaced
and should therefore be replaced before, during
and after exercise
– Athletes should have unlimited access to water
to prevent decrements in performance and
hypohydration
• 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
– Athletes was large muscle mass
– Overweight athletes (due to increased
metabolic rate)
– Death from heat stroke increase 4:1 as body
weight increases
– Women are physiologically more efficient with
regard body temp. regulation
– Others that are susceptible include, those with
poor fitness, history of heat illness, or febrile
condition
• 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% reduce blood volume and could
be a health threat
• Temperature and Humidity Reading
– Dry and wet bulb readings should be taken on
the field prior to practice to monitor heat index
– Modify practice according to severity of
environmental conditions
Guidelines for Athletes Who
Intentionally Lose Weight
• Predispose themselves to heat related
injuries and could create life-threatening
situations
• Weight loss should not be accomplished
through dehydration
• Gradual process over weeks and months
and should be a result of body fat lost
• NCAA and high school federations have
established guidelines for weight loss for
wrestling
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
• 65% of body heat is lost through radiation
(head and neck 50%)
• 20% through evaporation
• 2/3 through skin and 1/3 through respiration
• Problems arise when heat lost exceeds heat
production via metabolism
– Results in impairment of neuromuscular function
(which can also be impaired by shivering)
• Drop in core stimulates shivering but stops
after temp. drops below 85-90oF
• Death is imminent when temp falls below 7785oF.
• 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,
chilblains, and/or minor respiratory problems
– Be aware of hydration levels as well to enhance
blood volume and heat maintenance
• Common Cold Injuries
– Localized cooling can result in tissue damage
• Formation of ice crystals between cells, destroys
cells, disrupts blood flow, clotting may occur
– 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
• Chilblains result from prolonged exposure causing
redness and swelling, tingling pain in toes and
fingers
• Due to poor peripheral circulation
• 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
Altitude
• Most events do not occur at extreme heights
• As height decreases, maximum oxygen
uptake decreases resulting in a decrease in
performance
• Body compensates through tachycardia and
hyperventilation
• Responses as a result of fewer red blood
cells than necessary to adequately capture
available oxygen
• Adaptations
– Increased height = reduced barometric pressure
resulting in decreased partial pressure of
oxygen = less saturation of red blood cells
– Individual adaptations dependent on whether an
the person is a native, resident or visitor
• Resident has larger chest capacity, more alveoli,
capillaries and red blood cells
• Resident makes partial adaptations (increased
mitochondria and hemoglobin, glycogen
conservation)
• Visitor responds with increased breathing heart
action, hemoglobin, blood alkalinity, myoglobin and
changes in blood flow and enzyme activity
– Other uncertainties with regards to training and
competition
• Time to adjust (2-3 weeks vs. 3 days)
• Short adjustment allows acid-base balance to
recover but does not allow significant changes in
blood volume and maximum cardiac output
• Altitude Illnesses
– Acute Mountain Sickness
• 1 out of 3 will experience when making the jump
7000-8000 feet.
• Experience headache, nausea, vomiting, sleep
disturbance, and dypsnea
• Caused by brain disruption associated with sodium
potassium imbalance resulting in fluid retention and
cellular pressure changes
– Pulmonary Edema
• Occurs at 9000-10,000 feet.
• Lungs accumulate fluid in alveolar walls forming
pulmonary edema
• Signs and symptoms: dypsnea, cough, headache,
weakness and occasionally unconsciousness.
• Treat by moving athlete to lower altitude and providing
oxygen
– Sickle Cell Trait
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8-10% of African Americans have sickle cell trait
In most the trait is benign
Abnormality in red blood cell hemoglobin structure
When hemoglobin is deoxygenated, cells clump together
causing blood cell to develop sickle shape making it easy
to destroy
• Causes enlarged spleen and could rupture at high altitudes
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
– Damage to DNA is suspected as the cause of
cancer
– Major types include basal cell carcinoma,
squamous cell carcinoma and malignant
melanoma
– Rate of cure is 95% with early detection
– Fair skinned individuals are more susceptible to
these maladies
• 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
– Individuals with dark complexion should also
apply
– 60-80% of sun exposure occurs before the age
of 20
– 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
Lightening Safety
• #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 must
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
Air Pollution
• Major problem in urban areas, particularly
when considering large periods of exposure
• Two types
– Photochemical haze: nitrogen dioxide and
stagnant air acted on by sunlight to produce
ozone
– Smog: combination of carbon monoxide and
sulfur dioxide
• Ozone
– 3 atom molecule of oxygen
• reaction of oxygen, nitrogen oxides, hydrocarbons
and sunlight
– Minimum activity levels - ozone will not
impact
– Higher intensity will have a negative effect on
work output
– May experience shortness of breath, coughing,
chest tightness, pain with deep breathing,
nausea, eye irritation, fatigue, lung irritation,
lowered resistance to lung infection
– Asthmatics are at greater risk
– May desensitize to some degree over time
• Sulfur Dioxide
– Colorless gas that is a component of burning
coal or petroleum
– Causes increased resistance to air movement in
and out of the lungs, decreased ability of lungs
to rid themselves of foreign matter, shortness of
breath, coughing, fatigue and increased
susceptibility to lung diseases
– Adverse effects mostly on asthmatics
– Nose breathing lessens the effects due to
filtering of nasal mucosa
• Carbon Monoxide
– Colorless, odorless gas.
– Reduces hemoglobin’s ability to transport
oxygen and restricts release of oxygen to the
tissue
– Interferes with performance, and various
psychomotor, behavioral, and attention-related
activities
• Prevention
– To avoid problems, stop or decrease activity
during periods of high pollution
– Perform when commuter traffic is less and
ambient temperature is lower
– Avoid high times relative to ozone levels
– Running should be avoided in areas of high
traffic due to auto emissions and carbon
monoxide
Circadian Dysrhythmia (Jet Lag)
• Desynchronization of biological and
biophysical time clock
• Body maintains cyclical mechanisms over
24 hour periods (circadian rhythms)
– Changes in temperature, hormone levels)
• Body adapts over time to changes
– Immediately (protein metabolism)
– Over 8 days (body temperature)
– Three weeks (adrenal hormones)
• Jet lag refers to physical and mental effects
caused by traveling rapidly across time zones
– Disrupts circadian rhythms and sleep-wake cycles
• May cause fatigue, headaches, digestive disorder,
changes in blood pressure, heart rate, hormone and
endocrine releases, and bowel habits
• Could negative impact performance and predispose
athlete to injury
• May become ill, suffer short term anorexia, headaches,
blurred vision, dizziness, insomnia and/or fatigue
– Younger individuals adjust more rapidly
• 30-50% faster adaptation flying westward
• North-south travel has no impact unless time zones
are crossed
• Changes in zones, illumination and environment can
be disruptive (>5 time zones)
– To prevent
• Depart well rested
• Pre-adjust
– Eat according to time changes
– Avoid dehydration
– Training schedule
• Use caffeine when travelling west
• Adopt local time on arrival
• Avoid alcohol, before, during and after the trip
Synthetic Turf
• Believed to be:
– durable, offer great consistency, usable with
inclement weather, require less maintenance
– offer greater performance in areas of speed and
resiliency
• Variety of surfaces have been created since
1960’s
• Most recent is “resilient infill turf”
– Similar to grass, polyethylene and
polypropylene yarn on a base of sand, rubber
pellets or combination
• Constant debate
– Injury perspective- not conclusive evidence that
synthetic surface increases injury rates
– Empirically, athletes, coaches, and athletic trainers
agree that injuries are more likely on turf
• Most would prefer to play and practice on natural
surfaces
• Hybrid, more durable grasses are also available
– Synthetic surfaces
• Lose shock absorbing capabilities
• Injuries are more likely to occur when training always
occurs on turf
• Due to possibly of higher speeds as a result of turf,
injuries involving collisions could be more severe
due to increased force and impact
– Shoes that don’t “stick” will significantly
reduce likelihood of injury
– Common injuries
• Abrasions (reduce with padding)
• Turf toe (less likely to occur if shoes has stiff, firm
sole)