KIN 431 EXAM 2 QUESTIONS WITH
COMPLETE ANSWERS
How does water affect heat balance in the cold? - Answer-Only affects Convection: 30x
faster convection rates in the water compared to the air
- our microenvironment is constantly being swept away and replaced
- even warmer water decreases our core body temperature more than colder air does
(10 C water makes us colder than 0 C air)
What can happen as a result of initial cold shock? - Answer-- Hyperventilation: Drop in
CO2 causes less blood flow to the brain via vasoconstriction
- Cardiac arrhythmia: cold blood from our skin travels to our heart and cools it
What is the after-drop affect? - Answer-a brief drop in CBT after attempting to heat
someone up -> this makes things worse
- an external heating source (e.g. a person) causes the skin blood vessels to vasodilate
thereby sending blood from the core through colder layers to reach the skin -> when this
blood returns to the core, it is actually colder than before, causing a transient drop in
CBT
What is a shell and what does it consist of? - Answer-- we want to keep as much blood
as possible around the core in order to prevent CBT from dropping -> this causes the
outer layers to be much cooler
- consists of: skin, subQ fat, muscle, core
If you slip and fall in cold water, should you contract SM? - Answer-Depends on multiple
factors:
- which muscle groups - what temperature the water is
- SA:V ratio of the individual
- microenvironment
- prevent drowning
T or F: muscle contraction shrinks your shell in cold water, but this is sometimes okay
since muscle contraction generates heat - Answer-True
- muscle contraction causes there to be less insulation between the environment and
your core
Small muscle groups (upper body in particular) have a _________ SA:V - Answer-larger
- contracting smaller muscle groups actually exposes that SA to colder environments
since we are disrupting the microenvironment
Larger muscle groups (lower body in particular) have a ________ SA:V - Answer-
smaller
, - contracting larger muscle groups generates enough heat to counteract the heat that is
lost from disrupting the microenvironment
Should we contract if the water temperature is LESS than 59 degrees? - Answer-Don't
move in order to preserve the microenvironment
- movement causes increased heat transfer by introducing colder water
Should we contract if the water temperature is GREATER than 59 degrees? - Answer-
Some contraction should take place, because a disruption of the microenvironment
won't be as consequential since heat will be generated through muscle contraction
- more beneficial to contract lower body (larger) muscle groups due to the smaller SA:V
ratio
In general, smaller things have a _______ SA:V - Answer-larger
The larger the SA, the larger the ______ - Answer-heat transfer (heat loss in this case)
The larger the mass (volume), the greater the ______ - Answer-heat generated
How does fluid flow rate affect heat balance in the cold? - Answer-Convection: a greater
fluid flow rate disrupts your microenvironment at a faster rate than still water, which
leads to an even greater decline in core body temperature
What is critical temperature? - Answer-the environmental temperature that elicits a
shivering response
How does body composition affect heat balance in the cold? - Answer-Individuals with a
higher BF% have a thicker layer of insulation from that cold environment
How does sex affect heat balance in the cold? - Answer-Body size (SA:V)
- on average, males tend to be larger in size (smaller SA:V), so they will retain heat
better
- children will obviously have a larger SA:V, meaning they will transfer heat more quickly
(at greater risk of hypothermia)
Differences in body composition
- on average, females have a higher BF%, suggesting that they retain heat efficiently
- However, a female's larger SA:V plays a much greater role. They transfer heat more
quickly
Rank the following individuals in order from high to lower in terms of tolerance to a cold
environment (high tolerance = better able to withstand cold environmental
temperatures).
1 = Adult Male - Average Size & Average Body Composition,
2 = Adult Female - Average Size & Average Body Composition
COMPLETE ANSWERS
How does water affect heat balance in the cold? - Answer-Only affects Convection: 30x
faster convection rates in the water compared to the air
- our microenvironment is constantly being swept away and replaced
- even warmer water decreases our core body temperature more than colder air does
(10 C water makes us colder than 0 C air)
What can happen as a result of initial cold shock? - Answer-- Hyperventilation: Drop in
CO2 causes less blood flow to the brain via vasoconstriction
- Cardiac arrhythmia: cold blood from our skin travels to our heart and cools it
What is the after-drop affect? - Answer-a brief drop in CBT after attempting to heat
someone up -> this makes things worse
- an external heating source (e.g. a person) causes the skin blood vessels to vasodilate
thereby sending blood from the core through colder layers to reach the skin -> when this
blood returns to the core, it is actually colder than before, causing a transient drop in
CBT
What is a shell and what does it consist of? - Answer-- we want to keep as much blood
as possible around the core in order to prevent CBT from dropping -> this causes the
outer layers to be much cooler
- consists of: skin, subQ fat, muscle, core
If you slip and fall in cold water, should you contract SM? - Answer-Depends on multiple
factors:
- which muscle groups - what temperature the water is
- SA:V ratio of the individual
- microenvironment
- prevent drowning
T or F: muscle contraction shrinks your shell in cold water, but this is sometimes okay
since muscle contraction generates heat - Answer-True
- muscle contraction causes there to be less insulation between the environment and
your core
Small muscle groups (upper body in particular) have a _________ SA:V - Answer-larger
- contracting smaller muscle groups actually exposes that SA to colder environments
since we are disrupting the microenvironment
Larger muscle groups (lower body in particular) have a ________ SA:V - Answer-
smaller
, - contracting larger muscle groups generates enough heat to counteract the heat that is
lost from disrupting the microenvironment
Should we contract if the water temperature is LESS than 59 degrees? - Answer-Don't
move in order to preserve the microenvironment
- movement causes increased heat transfer by introducing colder water
Should we contract if the water temperature is GREATER than 59 degrees? - Answer-
Some contraction should take place, because a disruption of the microenvironment
won't be as consequential since heat will be generated through muscle contraction
- more beneficial to contract lower body (larger) muscle groups due to the smaller SA:V
ratio
In general, smaller things have a _______ SA:V - Answer-larger
The larger the SA, the larger the ______ - Answer-heat transfer (heat loss in this case)
The larger the mass (volume), the greater the ______ - Answer-heat generated
How does fluid flow rate affect heat balance in the cold? - Answer-Convection: a greater
fluid flow rate disrupts your microenvironment at a faster rate than still water, which
leads to an even greater decline in core body temperature
What is critical temperature? - Answer-the environmental temperature that elicits a
shivering response
How does body composition affect heat balance in the cold? - Answer-Individuals with a
higher BF% have a thicker layer of insulation from that cold environment
How does sex affect heat balance in the cold? - Answer-Body size (SA:V)
- on average, males tend to be larger in size (smaller SA:V), so they will retain heat
better
- children will obviously have a larger SA:V, meaning they will transfer heat more quickly
(at greater risk of hypothermia)
Differences in body composition
- on average, females have a higher BF%, suggesting that they retain heat efficiently
- However, a female's larger SA:V plays a much greater role. They transfer heat more
quickly
Rank the following individuals in order from high to lower in terms of tolerance to a cold
environment (high tolerance = better able to withstand cold environmental
temperatures).
1 = Adult Male - Average Size & Average Body Composition,
2 = Adult Female - Average Size & Average Body Composition
