RQ CH 12

The ability of hypothalamus to regulate body temperature is compromised when core temperature falls below 37 C (98.6 F) 34.5 C (94.1 F) 25 C (77 F ) The hypothalamus is not compromised by cold temperature

34.5 C (94.1 F)

When C, K, E, an R are considered together, heat transfer occurs 2 times faster in the air then 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 airt

Exercise-induced asthma in the cold affects as many as 10% of winter athletes 25% of winter athletes 50% of winter athletes 60% of winter athletes

50% of winter athletes

Which of these is NOT an effector controlled by the POAH? Skin arterioles Apocrine sweat glands Endocrine glands Skeletal glands

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 muscles

Contractile force decreases

Of the four major variables of heat transfer, which one is the 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

Endurance training causes sweat glands to Decrease electrolyte content of sweat secretion Delay onset of sweat secretion Decreases volume of sweat secretion Increases NA+ excretion through sweat secretion

Decrease electrolyte content of sweat secretion

Which of these hormones does NOT help control fluid balance during exercise? Aldosterone Antiduretic hormone Epinephrine Arginine Vasopressin

Epinephrine

During exercise int he 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

Acclimation is best achieved through Exercising at low-to-moderate intensity in the heat for 1/hr 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 3hr/day 2 times/wk Passively resting in a hot, humid environment

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

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 dehydrated conditions True False

False

Frostbitten tissue should be immediately rewarmed as quickly as possible True False

False

Higher circulating catecholamines during cold exposure contributes to higher FFA oxidation True False

False

When athletes train in the heat they are undergoing acclimatization True False

False

During exercise int he cold, the primary metabolic substrate is Free fatty acids due to increased circulating catecholamines Free fatty acids in spite of increased circulation 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 rapid, weak pulse, he or she most 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 Heatstroke

Heatstroke

Increased plasma volume with heat acclimation leads to Increased cardiac output and skin blood flow Higher heart rate Dangerous NA+ losses Lower sweat rate

Increased cardiac output and skin blood flow

Which of these is a response to a single bout of exercise in the heat? Reduced vasodilation of skin arterioles Increased vasodilation of skin arterioles Increased blood volume Increased stroke volume

Increased vasodilation of skin arterioles

Sweat glands functionally resemble which organ in the body? Liver Heart Kidneys Brain

Kidneys

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

The main cause of exercise-induced asthma is Cold Air Dry Air High respiratory rate B and C

Not Cold Air

Frostbite should be rewarmed Preferable 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 the 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 Restrict fluid intake Practice in full football gear Avoid outdoor practice or competition when WBGT is greater than 31 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 women Lean, muscular man

Slender Child

Excessive _____ losses are most closely 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

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

Suppression of shivering

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

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 that loss in the cold True False

True

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 mechanism True False

True

Swimming in 12 C water is more dangerous than running in 12 C air True False

True

The ultimate goal of heat acclimation is to reduce core temperature during exercise. True False

True

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 hear rate

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