493 Exam 2 - Ch 12

The ability of the hypothalamus to regulate body temperature is compromised when core temperature falls below

34.5 °C (94.1 °F)

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

4 times faster in water than in air

Exercise-induced asthma in the cold affects as many as

50% of winter athletes

Which of the following equations represents total heat gain by the body?

M - W ± R ± C ± K - E > 0

Which of these is NOT an effector controlled by the POAH?

apocrine sweat glands

The main cause of exercise-induced asthma is

b and c

Heat that the body gains from sitting on hot turf is categorized as

conduction

During exercise in the cold, muscle

contractile force decreases

Of the four major variables of heat transfer, which one is most important for daily living?

convection

As windchill becomes greater, ___________________.

convective heat loss increases

When an athlete is exercising in hot and humid weather

core temperature will increase faster

Endurance training causes sweat glands to

decrease electrolyte content of sweat secretion

Which of these hormones does NOT help control fluid balance during exercise?

epinephrine

During exercise in the heat, the body's primary means of heat loss is

evaporation

The primary source of heat loss during exercise in the heat is

evaporation

The critical temperature theory suggests that

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 h/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.

false

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

false

Frostbitten tissue should immediately be rewarmed as quickly as possible.

false

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

false

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

false

During exercise in the cold, the primary metabolic substrate is

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

_______________ is most effectively treated using whole-body immersion in an ice bath.

heatstroke

Increased plasma volume with heat acclimation leads to

increased cardiac output and skin blood flow

Which of these is a response to a single bout of exercise in the heat?

increased vasodilation of skin arterioles

Sweat glands functionally resemble which organ in the body?

kidneys

Frostbite should be rewarmed

preferably in a hospital

Heat that the body gains from the sun on a cloudless day is categorized as

radiation

Heat cramps must be treated with

rapid sodium replenishment

When sweat glands become more sensitive to aldosterone after acclimation, they

reduce sweat's sodium content

A good way to minimize the chance of hyperthermia is to

schedule early-morning and evening practices

Whose body morphology will lead to the most heat loss at a given cold temperature?

slender child

Excessive _________ losses are most closely associated with heat cramps.

sodium

In the heat, clothing functions as all of these EXCEPT

source of radiation

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

suppression of shivering

Women sweat less than men at the same relative exercise intensity because

they produce less sweat per sweat gland

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

true

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

true

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

true

Sweating and skin vasodilation are the body's only physiological heat loss mechanisms.

true

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

true

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

true

Which of these occurs during cardiovascular drift?

upward drift in heart rate

Which of the following variables is most important in determining whether hot environmental conditions are safe for competition?

wet bulb temperature