Chapter 14- Exercise in Hot and Cold Environments

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

- exercise is shut down when a given core temperature is reached

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

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

T/F Although the majority of ATP breakdown contributes to cellular work approximately 25% of it contributes to metabolic heat production.

F

T/F Fluid intake should be restricted during training to help the body adapt to dehydrated conditions.

F

T/F Higher circulating catecholamines during cold exposure contribute to higher FFA oxidation.

F

_______________ is most effectively treated using whole-body immersion in an ice bath. Heat illness Heat cramps Heat exhaustion Heatstroke

Heatstroke

In the heat clothing functions as all of these except a. resistance to dry heat exchange b. source of radiation c. resistance to evaporative heat loss d. insulation

Source of radiation

Although the majority of ATP breakdown contributes to cellular work, approximately 25% of it contributes to metabolic heat production (T/F)?

T

As air temperature reaches skin temperature, convection becomes an avenue of heat gain (T/F)

T

T/F As air temperature reaches skin temperature convection becomes an avenue of heat gain.

T

T/F Body composition and size have a significant impact on heat loss in the cold.

T

T/F Sweating and skin vasodilation are the body's only physiological heat loss mechanisms.

T

T/F Swimming in 12 °C water is more dangerous than running in 12 °C air.

T

T/F The ultimate goal of heat acclimation is to reduce core temperature during exercise.

T

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

a) slender child

Heat that the body gains from sitting on hot turf would be categorized as a. conduction b. convection c. evaporation d. radiation

a. conduction

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

a. core temperature will increase faster

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 is mostly likely suffering from a. heat exhaustion b. heat illness c. heat cramps d. heatstroke

a. heat exhaustion

increased plasma volume with heat acclimation leads to a. increased cardiac output and skin blood flow b. higher heart rate c. dangerous Na+ losses d. lower sweat rates

a. increased cardiac output and skin blood flow

Which of these occurs during cardiovascular drift? a. upward drift in heart rate b. upward drift in cardiac output c. upward drift in stroke volume d. upward drift in skin vasodilation

a. upward drift in heart rate

Of the four major heat transfer variables which one is most important for daily living? a. conduction b. convection c. evaporation d. radiation

b. convection

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

b. increased vasodilation of skin arterioles

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

c. M - W ± R ± C ± K - E > 0

Which of these hormones does not help control fluid balance during exercise? a. aldosterone b. antidiuretic hormone c. epinephrine d. arginine vasopressin

c. epinephrine

Heat cramps must be treated with a. rapid potassium replenishment (e.g., bananas) b. rapid water replenishment c. rapid sodium replenishment d. rapid calcium replenishment

c. rapid sodium replenishment

During exercise in the cold muscle

contractile force decreases

As windchill becomes greater, ___________________. evaporative heat loss increases convective heat loss increases radiative heat loss increases conductive heat loss increases

convective heat loss increases

When an athlete is exercising in hot and humid weather 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

core temperature will increase faster

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

d. all three temperatures are equally important

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

d. exercise is shut down when a given core temperature is reached

Heat that the body gains from the sun on a cloudless day would be categorized as a. conduction b. convection c. evaporation d. radiation

d. radiation

A good way to minimize the chance of hyperthermia is to a. restrict fluid intake b. practice in full football gear c. avoid outdoor practice or competition when WBGT >31 °C d. schedule early-morning and evening practices

d. schedule early-morning and evening practices

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

decrease electrolyte content of sweat secretion

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

evaporation

When C K E and R are considered together heat transfer occurs

four times faster in water than in air

During prolonged exercise in the heat, which of the following variables increases due to dehydration? stroke volume heart rate mean arterial pressure cerebral blood flow

heart rate

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 most likely has?

heat exhaustion

Sweat glands functionally resemble which organ in the body?

kidneys

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

suppression of shivering

If muscle glycogen and blood glucose both start to run low during exercise in the cold what is the consequence?

suppression of shivering

When sweat glands become more sensitive to aldosterone after acclimation

they reduce sweat's sodium content