Prentice Ch. 6 - Environmental Considerations Flashcards Preview

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Flashcards in Prentice Ch. 6 - Environmental Considerations Deck (84):


elevated body temperature


metabolic heat production

the higher the metabolic rate, the more heat produced


heat can be gained or lost though:

1. metabolic heat production
2. conductive heat exchange
3. convective heat exchange
4. radiant heat exchange
5. evaporative heat loss


Conductive Heat exchange

physical contact with other objects can result in either a heat loss or a heat gain
ex. standing on turf


Convective heat exchange

occurs when a mass of either air or water moves around an individual, body heat is either lost or gained
ex. cool wind


Radiant Heat Exchange

radiant heat from sunshine causes an increase in body temperature
- during exercise the body attempts to dissipate heat produced by metabolism by dilating superficial arterial and venous vessels thus channeling blood to the superficial capillaries in the skin.


Evaporative Heat Loss

sweat glands in the skin allow water to be transported to the surface, where it evaporates, taking large quantities of heat with it.


Rate of sweat

- normal person can sweat off about 1 quart of water per hour for about 2 hours.
- however, certain individuals can lose as much as 2 quarts of water (4 lbs) per hour
- sweat must evaporate for heat to be dissipated


Impairing heat loss

it is impaired when relative humidity reaches 65% and virtually stops when the humidity reaches 75%


Prevention of hyperthermia

- appropriate hydration
- unrestricted fluid and electrolyte replacement
- gradual acclimatization
- identification of susceptible individuals
- appropriate uniforms
- weight records
- monitoring of the heat index



- ingesting sufficient fluids in the 24 hrs before exercise


Mild Dehydration

- loss of less than 2% of body weight
- rehydrate with sports drink/water
- fluid intake should = fluid loss


sweat loss/fluid replacement

- normal sweat loss for a person doing an hour of exercise ranges between 0.8 and 3L with an avg. of 1.5L/hr
- once body weight drops to 1-2% the individual becomes thirsty
- by the time thirst develops the body is already slightly dehydrated
- most people replace only 50% of the water they lose


Electrolyte replacement

- well formulated sports drink is more effective than using water alone


Why is water a bad rehydrator

- water is a good thirst quencher but it is not a good rehydrator because it turns off thirst before the body is completely rehydrated


sports drinks best formulation

14g per 8oz of water of carbohydrate (6% carbohydrate) produces the quickest fluid absorption


Gradual Acclimatization

- a good preseason conditioning program started well before the advent of the competitive season and carefully grades as to intensity is recommended


Gradual Acclimatization timeline

- 7-10 days
- the first 5-6 days an 80% acclimatization can be achieved by 2 hr practice period in the morning & in the afternoon


practice breakdown

20 mins of work with 20 mins of rest in the shade


Identifying susceptible individuals

- overweight/large muscle mass


Selecting appropriate uniforms

- should be selected on basis of temperature and humidity
- initial practices should be in t-shirts shorts and socks
- move gradually into short-sleeved net jerseys & lightweight pants


Maintaining weight records

- weights should be measured both before and after practice for at least the first 2 weeks of practice or as long as hot, humid conditions persist
- a loss of greater than 2% of body weight indicates that the athlete is severely dehydrated and should be held out of practice until normal body weight has returned



- wet bulb globe temperature
- provides the ATC with an objective means for determining necessary precautions for practice and competition in hot weather


Dry bulb temperature (DBT)

- recorded from a standard mercury thermometer


Wet bulb temperature (WBT)

- recorded from a wet wick or piece of gauze wrapped around the end of a thermometer that is swung around in the air


Globe Temperature (GT)

measures the suns radiation and has a black metal casing around the end of the thermometer


WGBT equation

WBGT = 0.1 x DBT + 0.7 x WBT + GT x 0.2


Equation for only WBT & DBT

WBGT = 0.3 x DBT + 0.7 x WBT



- two identical thermometers - when cloth is soaked the thermometers are properly ventilated
- the wet bulb temp will be lower than the dry club because of the cooling due to the evaporation of the water from the cloth
- takes around 90 seconds
- old sling psychrometer may have the greatest accuracy


Heat Rash

- also called prickly heat
- benign condition
- sensations of prickling and tingling during sweating
- usually occurs when the skin is continuously wet with unevaporated sweat
- localize to areas covered with clothing
- continually toweling the body can help prevent the rash from developing


Heat Syncope

- also called heat collapse
- rapid physical fatigue during overexposure to heat
- occurs from by standing in heat for long periods or by not being accustomed fro exercising in the heat


Heat Syncope cause

- caused by vasodilation of superficial vessels, hypotension or a pooling of blood in the extremities which results in dizziness, fainting and nausea


Heat Syncope relief

- laying athlete down in a cool environment, elevating the lower extremities and replacing fluids


Exertional Heat Cramps

- painful muscle spasms and cramps that occur mainly in the lower extremities and abdomen


Exertional Heat Cramp cause

- excessive loss of water and several electrolytes or ions (sodium, chloride, potassium, magnesium, and calcium) but especially sodium
- its caused by an imbalance of water and electrolytes


People who get Heat Cramps

- in fairly good condition
- but is not acclimatized to the heat


Heat Cramp Prevention

- adequate replacement of sodium, chloride, potassium, magnesium, calcium and most important, fluids
- ingestion of salt tablets
- simply salting food might also replace sodium levels
- eat a banana, milk/cheese


Immediate treatment of Heat Cramps

- ingestion of large quantities of fluids preferably a sports drink, and mild, prolonged stretching with ice massage of the muscle in spasm


Exertional Heat Exhaustion

- occurs from environmental heat stress and strenuous physical exercise


Exertional heat exhaustion causes

- dehydration
- becomes unable to sustain adequate cardiac output and thus cannot continue intense exercise


heat exhaustion signs & symptoms

- rectal temperature of below 104
- no evidence of CNS dysfunction
- dehydration/electrolyte depletion
- pale skin
- profuse sweating
- stomach cramps
- vomiting or diarrhea
- headache
- persistent muscle cramps
- dizziness with loss of coordination


heat exhaustion treatment

- immediately remove them from play
- take to a shaded area
- or air conditioning
- excess clothing should be removed
- lie them down with legs elevated
- rectal temp should be lowered to 101 degrees
- water and sports drinks as long as they aren't nauseous or vomiting
- IV fluids if can't orally
- continuously monitor HR, BP and core temperature
- if rapid improvement is not seen they needed to be transported


Exertional Heatstroke

- life threatening
- induced by strenuous physical exercise and increased environmental heat stress


Heatstroke Characterized

CNS abnormalities and potential tissue damage resulting from a significantly elevated body temperature
- can occur suddenly and without warning
- altered consciousness
- seizures
- confusion
- emotional instability
- rectal temp is 104 or above
- hot flushed skin
- sweating about 75 percent of the time


other symptoms of heatstoke

- shallow fast breathing
- rapid strong pulse
- nausea or vomiting
- diarrhea
- headache
- dizziness or weakness
- decreased blood pressure
- dehydration
- body loses the ability to dissipate heat through sweating


What to do with heatstroke

- get athlete into a cool environment, strip of all clothing and immerse the athlete in a cold-water bath (35-58 degrees)
- if no bath you must sponge with cool water and a fan with a towel
- place ice at neck, armpits, under knees (major arteries)
- lower rectal temp to 101
- call the rescue squad
- cool first then transport


RTP heatstroke

-exercise for a minimum of 1 week and gradually return to full practice after being completely asymptomatic and cleared by a physician


Malignant Hyperthermia

- rare
- genetic
- inherited
- hypersensitivity to anesthesia and extreme exercise in hot environments
- characterized by muscle breakdown


Malignant Hyperthermia S&S

- muscle pain after exercise
- rectal temp remains elevated for 10 to 15 minutes after exercise
- can cause acute renal failure
- can be fatal if not treated immediately
- should be disqualified from competing in hot humid environments


Acute Exertional Rhabdomyolysis

- sudden catabolic destruction and degeneration of skeletal muscle accompanied by leakage of myoglobin (muscle protein) into the vascular system


Rhabdo S&S

- happens during intense exercise in extremely hot and humid environmental conditions
- gradual onset of muscle weakness, swelling and pain in the presence of darkened urine and renal dysfunction
- sever cases see sudden collapse, renal failure and death
- associated with sickle-cell trait


Exertional Hyponatremia

- fluid/electrolyte disorder that results in an abnormally low concentration of sodium in the blood
- usually caused by ingesting so much fluid before, during and after exercise that the concentration of sodium is decreased
- can be too little salt in the diet


Hyponatremia information

- athlete who has a high rate of sweating, and a significant loss of sodium, continues to ingest large quantities of fluid over a several-hour period of exercise
- marathon runners
- can be avoided obviously


Hyponatremia S&S

- worsening headache
- nausea and vomiting
- swelling of the hands and feet
- lethargy
- apathy
- agitation
- low blood sodium


Guidelines for athletes who intentionally lose weight

- weight loss to make a predetermined weight limit should not be accomplished though dehydration
- should be over several weeks or even months
- result from a reduction in the percentage of body fat relative to lean body mass



- abnormally low body temperature


Conditions needed for hypothermia

- cold
- wind
- dampness


Where is heat lost?

- 65% of the heat produced by the body is lost through radiation
- loss occurs though the head and neck which may account for as much as 50% of the loss
- 20% of heat loss is though evaporation of which 2/3 is though the skin and 1/3 is though the respiratory tract



- ceases below a body temperature of 85 degrees to 90 degrees
- death is imminent if the core temp drops to between 77 degrees


Prevention of hypothermia

- clothing provides a semi tropical climate
- clothing should not restrict movement
- should be as lightweight as possible
- permit the free passage of sweat and body heat
- rehydrate! increase in blood volume = increase in body heat


Frost Nip

- affects ears, nose, cheeks, chin, fingers, and toes
- skin appears very firm with cold painless areas the may peel or blister in 24 to 72 hours
- treat with sustained pressure
- no rubbing!
- blowing hot breath on the spot
- place arms in the armpits


Frostbite (chilblains)

- result of prolonged cold
- skin redness, swelling, tingling, and pain in the toes and fingers
- caused by problems of peripheral circulation


Superficial frostbite

- skin and subcutaneous tissue
- pale, hard, cold, and waxy
- palpation will show hardness but with yielding of the undying tissue structures


superficial frostbite treatment

- immerse in warm water 100-110F
- first few numb the sting and burn.
- do not rub
- later there may be blisters and be painful for a number of weeks


Deep Frostbite

- serious injury
- same shit as superficial frostbite
- can become gangrenous causing a loss of tissue


Altitude sickness

- mexico city elevation: 7,600 feet
- there is a 7-8% decrease in maximum o2 uptake
- represents a 4-8% deterioration in performance
- when the body is suddenly without its usual o2 supply, hyperventilation can occur


Adaptation to altitude

- depends on resident, native, or visitor
- adaptation includes; conservation of glucose, increased number of mitochondria, and increased formation of hemoglobin


Adaptation to altitude: visitors

- responses include:
- increased breathing
- increase heart action
- increased hemoglobin
- increase blood alkalinity
- increased myoglobin
- dehydration


Athletes going into high altitude

- experts suggest arriving 2-3 weeks before competition to provide the best adjustment period
- some also suggest that 3 days before competition is enough time


Acute Mountain Sickness

- low to moderate altitude of 7000 to 8000 feet
- headache
- nausea
- vomiting
- sleep disturbance
- dyspnea
- can last up to 3 days
- tissue disruption in the brain and affects sodium/potassium balance


High Altitude Pulmonary Edema (HAPE)

- 9000 to 10,000 feet
- lungs accumulate a small amount of fluid within the alveolar walls (usually absorbed in a few days)
- dyspnea
- cough
- headache
- weakness
- unconsciousness
- move athlete to lower altitudes


High Altitude Cerebral Edema (HACE)

- usually in conjunction with HAPE
- leads to coma or death
- happens in 1% of people above 9,000 feet
- increased cerebral blood flow due to the increased permeability of cerebral endothelium when exposed to hypoxia
- increased intracranial pressure


Sickle-Cell Trait Reaction

- occurs in 8%-10% of African Americans
- abnormality of the structure of the red blood cells and their hemoglobin content
- hemoglobin becomes deoxygenated as a result of exercise at a high altitude the cells tend to clump together
- abnormal sickle shape that can be destroyed easily
- can cause an enlarged spleen



sun protection factor
- an SPF of 6 indicates that an athlete can be exposed to UV light six time longer than without a sunscreen before the skin begins to turn red
- 60 to 80 percent of lifetime sun exposure is often obtained by age 20


people who need higher SPFs

- light skinned
- blue eyes
- fair hair
- or skin that burns easily
- people over 6 months of age


Lightening safety EAP

- chain of command as to who should monitor both weather forecast and changing weather of a threatening nature and to determine who makes the decision to remove from and return a team to the practice field


General rule for lightening

if you hear thunder or see lightning you are in immediate danger and should seek a protective shelter in an indoor facility at once


If you feel your hair stand on end..

get in the fetal position on the ground
stay away from trees or lighting posts
- low ground
- don't lie flat


flash to bang ratio

number of seconds from lightning flash until the sound of thunder divided by 5 to determine the distance from the lightning strike
- if the count is at 30 or less there is danger and conditions should be monitored
- if the count reaches 30 everyone should leave the field for shelter


can return to field after...

30 minutes have passed from either the last lightning strike or thunder clap


lightning detectors

monitors lightning at a distance of 40 miles
- if the detector flashes 3-8 range this is generally considered to be life threatening



at its highest level when higher temperatures and the increased amount of sunlight during the summer combine with stagnant atmospheric conditions


Ozone S&S

shortness of breath
chest tightness
pain during deep breathing
eye irritation
lung irritation
lowered resistance to lung infections


Nitrogen dioxide

produced by cars
irritate the lungs
lower resistance to RI
acute respiratory disease in children