Cold Exposure and Hypothermia

Question 1

What are different types of heat loss?

Answer 1

Radiation: loss if ambient temp is Loss of heat from sweating and respiration

Question 2

What part of the brain regulates body temp?

Answer 2

The hypothalamus is the major center of the brain for regulating body temperature. It is sensitive to blood temperature changes of as little as 0.5 degrees Celsius and also reacts to nerve impulses received from nerve endings in the skin

Question 3

Above____F many body enzymes become denatured and chemical reactions cannot take place leading to death

Answer 3

105 F

Question 4

Core Temp is the temperature of____?

Answer 4

the internal body organs, particularly the heart, lungs, and brain.

Question 5

How does the body regulate core temp/

Answer 5

1. Vasodilation - increases surface blood flow, increases heat loss (when ambient temperature is less that body temperature). Maximal vasodilation can increase cutaneous blood flow to 3000 ml/minute (average flow is 300-500 ml/minute).
2. Vasoconstriction - decreases blood flow to periphery, decreases heat loss. Maximal vasoconstriction can decrease cutaneous blood flow to 30 ml/minute.
3. Sweating - cools body through evaporative cooling
4. Shivering - generates heat through increase in chemical reactions required for muscle activity. Visible shivering can maximally increase surface heat production by 500%. However, this is limited to a few hours because of depletion of muscle glucose and the onset of fatigue.
5. Increasing/Decreasing Activity will cause corresponding increases in heat production and decreases in heat production.
6. Behavioral Responses - putting on or taking off layers of clothing will result in heat regulation

Question 6

Definition of hypothermia?

Answer 6

“decrease in the core body temperature to a level at which normal muscular and cerebral functions are impaired.” -

Question 7

What are “hypothermia” temperatures?

Answer 7

**Any temp below 98.6 can lead to hypothermia

Question 8

What are signs and symptoms of hypothermia?

Answer 8

Watch for the “-Umbles” - stumbles, mumbles, fumbles, and grumbles which show changes in motor coordination and levels of consciousness

Question 9

What are signs and symptoms of Mild

hypothermia(core temp of 96-98.6F) ?

Answer 9

Shivering - not under voluntary control
Can’t do complex motor functions (ice climbing or skiing) can still walk & talk
Vasoconstriction to periphery

Question 10

What are signs and symptoms of Moderate Hypothermia - core temperature 95 - 93 degrees F ?

Answer 10

Dazed consciousness
Loss of fine motor coordination - particularly in hands - can’t zip up parka, due to restricted peripheral blood flow
Slurred speech
Violent shivering
Irrational behavior - Paradoxical Undressing - person starts to take off clothing, unaware s/he is cold
“I don’t care attitude” - flattened affect

Question 11

What are signs and symptoms of Severe Hypothermia - core temperature 92 - 86 degrees and below (immediately life threatening)

Answer 11

Shivering occurs in waves, violent then pause, pauses get longer until shivering finally ceases - because the heat output from burning glycogen in the muscles is not sufficient
to counteract the continually dropping core temperature, the body shuts down on shivering to conserve glucose
Person falls to the ground, can’t walk, curls up into a fetal position to conserve heat
Muscle rigidity develops - because peripheral blood flow is reduced and due to lactic acid and CO2 buildup in the muscles
Skin is pale
Pupils dilate
Pulse rate decreases
at 90 degrees the body tries to move into hibernation, shutting down all peripheral blood flow and reducing breathing rate and heart rate.
at 86 degrees the body is in a state of “metabolic icebox.” The person looks dead but is still alive.