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