chapter 12

The ability of the hypothalamus to regulate body temperature is compromised when core temperature falls below -37 degrees C -34.5 degrees C -25 degrees C -the hypothalamus is not compromised by cold temperatures

34.5 degrees C

When C, K, E, and R are considered together, heat transfer occurs -2 times faster in air than in water -4 times faster in water than in air -6 times faster in air than in water -26 times faster in water than in air

4 times faster in water than in air

Exercise-induced asthma in the cold affects as many as -10% of winter athletes -25% of winter athletes -50% of winter athletes -70% of winter athletes

50% of winter athletes

Which of the following equations represents total heat gain by the body? -M - W ± R ± C ± K - E = 0 -M - W ± R ± C ± K - E < 0 -M - W ± R ± C ± K - E > 0 -M - W ± R ± C ± K - E = 0.1Tdb + 0.7Twb + 0.2Tg

M - W ± R ± C ± K - E > 0

Which of these is NOT an effector controlled by the POAH? -skin arterioles -apocrine sweat glands -endocrine glands -skeletal muscle

apocrine sweat glands

Heat that the body gains from sitting on hot turf is categorized as -conduction -convection -evaporation -radiation

conduction

During exercise in the cold, muscle -shortening velocity increases -contractile force decreases -fiber recruitment generates more power -contraction is inhibited only in deep muscle

contractile force decreases

Of the four major variables in heat transfer, which one is most important for daily living? -conduction -convection -evaporation -radiation

convection

As windchill becomes greater, _________ -convective heat loss increases -conductive heat loss increases -radiative heat loss increases -evaporative heat loss increases

convective heat loss increases

When an athlete is exercising in hot and humid weather -core temperature will increase faster -evaporation will be enhanced -convection will be the only usable method of heat transfer -clothing will help sweat evaporate better

core temperature will increase faster

Acclimation is best achieved through -exercising at low-to-moderate intensity in the heat for 1 h/day for 9 to 14 days -using metabolic heat from exercising as the primary stimulus for acclimation -exercising at moderate intensity in the heat for 3 h/day, 2 times/week -passively resting in a hot, humid environment

exercising at low-to-moderate intensity in the heat for 1 h/day for 9 to 14 days

Frostbitten tissue should immediately be rewarmed as quickly as possible. -true -false

false

Higher circulating catecholamines during cold exposure contribute to higher FFA oxidation. -true -false

false

When athletes train in the heat, they are undergoing acclimatization. -true -false

false

Which of these is a response to a single bout of exercise in the heat? -reduced vasoconstriction in nonessential tissues -increased vasodilation of skin arterioles -increased blood volume -increased stroke volume

increased vasodilation of skin arterioles

Women sweat less than men at the same relative exercise intensity because -they produce less sweat per sweat gland -they have fewer sweat glands -they do not acclimatize to heat as quickly -their plasma volume is lower

they produce less sweat per sweat gland

For thermoregulatory purposes, the body can be divided into two major compartments: the superficial shell and the deep core -true -false

true

Sweating and skin vasodilation are the body's only physiological heat loss mechanisms -true -false

true

Swimming in 12 degrees C water is more dangerous than running in 12 degrees C air. -true -false

true

The ultimate goal of heat acclimation is to reduce core temperature during exercise. -true -false

true

If muscle glycogen and blood glucose both start to run low during exercise in the cold, what is the consequence? -frostbite -suppression of shivering -enhanced skin vasoconstriction -rewarming of extremities

uppression of shivering

Which of these occurs during cardiovascular drift? -upward drift in heart rate -upward drift in cardiac output -upward drift in stroke volume -upward drift in skin vasodilation

upward drift in heart rate

Endurance training causes sweat glands to -decrease electrolyte content of sweat secretion -delay onset of sweat secretion -decrease volume of sweat secretion -increase Na+ excretion through sweat secretion

decrease electrolyte content of sweat secretion

Which of these hormones does NOT help control fluid balance during exercise? -aldosterone -antidiuretic hormone -epinephrine -arginine vasopressin

epinephrine

During exercise in the heat, the body's primary means of heat loss is -evaporation -conduction -convection -radiation

evaporation

The primary source of heat loss during exercise in the heat is -conduction -convection -evaporation -radiation

evaporation

The critical temperature theory suggests that -sweating does not begin until a given core temperature is reached -hypothermia symptoms do not appear until a given core temperature is reached -skin vasodilation does not occur until a given core temperature is reached -exercise is shut down when a given core temperature is reached

exercise is shut down when a given core temperature is reached

Although the majority of ATP breakdown contributes to cellular work, approximately 25% of it contributes to metabolic heat production. -true -false

false

Fluid intake should be restricted during training to help the body adapt to dehydration conditions. -true -false

false

During exercise in the cold, the primary metabolic substrate is -free fatty acids due to increased circulating catecholamines -free fatty acids in spite of increased circulating catecholamines -glucose/glycogen due to increased circulating catecholamines -glucose/glycogen in spite of increased circulating catecholamines

glucose/glycogen in spite of increased circulating catecholamines

If core temperature is not excessively high but an athlete is still exhibiting dizziness, nausea or vomiting, and a rapid, weak pulse, he or she mostly likely has -heat exhaustion -heat illness -heat cramps -heatstroke

heat exhaustion

_______ is most effectively treated using whole-body immersion in an ice bath -heat exhaustion -heat illness -heat cramps -headstroke

heatstroke

Increased plasma volume with heat acclimation leads to -increased cardiac output and skin blood flow -higher heart rate -dangerous Na+ losses -lower sweat rates

increased cardiac output and skin blood flow

Sweat glands functionally resemble which organ in the body? -liver -heart -kidneys -brain

kidneys

Frostbite should be rewarmed -preferably in a hospital -as fast as possible to avoid gangrene -and then refrozen to confer cold resistance -by vigorous rubbing to promote blood flow

preferably in a hospital

Heat that the body gains from the sun on a cloudless day is categorized as -conduction -convection -evaporation -radiation

radiation

Heat cramps must be treated with -rapid potassium replenishment (e.g., bananas) -rapid water replenishment -rapid sodium replenishment -rapid calcium replenishment

rapid sodium replenishment

When sweat glands become more sensitive to aldosterone after acclimation, they -reduce the volume of sweat that is secreted -secrete sweat at a lower core temperature -increase the volume of sweat that is secreted -reduce sweat's sodium content

reduce sweat's sodium content

A good way to minimize the chance of hyperthermia is to -restrict fluid intake -practice in full football gear -avoid outdoor practice or competition when WBGT is greater than 31 degrees C -schedule early-morning and evening practices

schedule early-morning and evening practices

Whose body morphology will lead to the most heat loss at a given cold temperature? -slender child -obese man -overweight woman -lean, muscular man

slender child

Excessive _______ losses are most clearly associated with heat cramps. -potassium -calcium -magnesium -sodium

sodium

In the heat, clothing functions as all of these EXCEPT -resistance to dry heat exchange -source of radiation -resistance to evaporative heat loss -insulation

source of radiation

As air temperature reaches skin temperature, convection becomes an avenue of heat gain. -true -false

true

Body composition and size have a significant impact on heat loss in the cold. -true -false

true

Which of the following variables is most important in determining whether hot environmental conditions are safe for competition? -dry-bulb temperature -globe temperature -wet-bulb temperature -all three temperatures are equally important

wet-bulb temperature