Flashcards in Deck 4 Deck (42):
Humans can tolerate a decline in deep body temp of ____ C but an increase of only ____C.
How does the body sense temp change?
- Thermal receptors in the skin
- blood temp changes that perfuse hypothalamus
Body emits electromagnetic heat waves. No molecular contact between objects.
Direct heat transfer from one molecule to another through a liquid, solid, or gas. Heat loss involves warming air molecules & cooler surfaces that contact skin.
Air or water moving across skin
What is the major defense against overheating?
3 Major factors influence amount of sweat vaporized from skin:
- surface exposed to environment
- temperature and humidity
- convective air currents around body
What reduces evaporation the most?
high humidity at lower temperatures
Why may muscles not receive adequate amounts of blood during exercise in very hot conditions?
The warm blood moves to the periphery to cool off skin
Loss of body mass due to fluid loss
A 3-5% loss of body mass degrades muscular strength and anaerobic performance (TRUE/FALSE)
Crucial water deficit is considered:
>2% loss of body mass
Fluid loss coincides with 5 factors:
- decreased plasma volume
- reduced skin blood flow
- reduced SV
- increased HR
- general deterioration in circulatory & thermoregulatory efficiency in exercise
Factors that Modify Heat Tolerance:
- training status
- % body fat
Increased cutaneous blood flow; sweat output; exercise tolerance time are all examples of:
What happens when you get older that alters heat tolerance?
- altered thirst metabolism
- lower blood volume
- lower skin blood flow
How does % body fat modify heat tolerance?
More fat acts as insulation, so more difficult to conduct heat to periphery
Can heat syncope occur with little to no change in core body temperature?
When having heat cramps you should drink water that contains salt (TRUE/FALSE)
What is the most common form of serious heat illness?
Failure of heat-regulating mechanisms from an excessively high core temperature is:
What should the temperature in an exercise environment be?
If outside temperature is increased, this increases core body temperature; what does this do to cardiac demands?
Increases them because the heart must pump more blood periphery to cool
Do endocrine or exocrine glands contain ducts and carry substances to a specific surface?
Hormones secreted from what type of gland enter the blood and travel to different tissues?
Extent of target cell’s activation by hormone depends on:
- hormone concentration
- number of target cell receptors
- sensitivity/strength between hormone and receptor
What three factors stimulate endocrine gland activity?
Hormonal, humoral, and neural
Why would trained individuals show a decreased rise in blood GH levels compared to untrained?
Because their body is able to use smaller amounts of GH more efficiently
Who has lower testosterone, runners or sedentary individuals?
Does training increase or decrease ATCH release during exercise?
Do plasma cortisol levels increase more or less in trained subjects?
What three factors contribute to greater catecholamine output during exercise?
- greater demand for substrate use via glycogenolysis and lipolysis
- increased cardiovascular response
- larger muscle mass activation
Endurance training maintains blood levels of insulin and glucagon closer to resting levels during physical activity. (TRUE/FALSE)
TRUE (no spikes)
A single bout of moderate or intense physical activity decreases plasma glucose levels for up to three days (TRUE/FALSE)
What does improved insulin sensitivity via exercise mean?
As you exercise, your body is able to utilize insulin more efficiently and less insulin needs to be released to get the same effect
Resistance + endurance training improves markers of insulin resistance and body composition more than endurance training alone. (TRUE/FALSE)
Improvements in glucose homeostasis with regular physical activity rapidly decreases when training ceases and completely dissipates within several weeks. (TRUE/FALSE)
Endurance athletes who consume carbohydrate during a race experience a lower disruption in hormonal and immune measures than athletes who do not consume carbohydrate (TRUE/FALSE)
The female athlete triad is defined as:
1.) low energy availability (w/ or w.o eating disorder)
2.) menstrual dysfunction
3.) low BMD occurring in physically active girls and women
All three components of FEAT are linked, but it is likely that the combination of menstrual dysfunction and disordered eating gives rise to poor bone mineralization (TRUE/FALSE)
How does lack of estrogen impact BMD?
Estrogen decreases absorption and deposition of calcium into the bone matrix