how cold affects the body
How Cold Affects The Body
B Y: G E N E S I S P O N C E
How Cold Affects The Body
The body tries to maintain body temperature by
vasoconstriction and shivering.
Shivering is the body’s main involuntary defense against the cold producing body heat by forcing muscles to contract and relax rapidly. Vasoconstriction is the tightening of blood vessels
Vasoconstriction occurs in the uncovered skin when it is exposed to cold temperatures.
The reduced blood flow in the skin conserves body heat but can lead to discomfort, numbness, loss of dexterity in the hands and fingers. How The Body Produces Heat
Normal body temperature is maintained by a
balance of heat production and heat loss
Heat is produced by food metabolism and
muscle activity.
Shivering increases heat production up to 500%
lack of food limits the body’s ability to
produce heat.
Heat Loss From The Body
Body heat can be lost by four mechanisms.
1. Convection is the loss of heat from the body by air blowing over the skin or through clothing.
2. Conduction, or direct contact with a colder object.
For example, lying in snow but with the exception of being immersed in cold water; Heat is then lost 25 to 30 times faster.
3. Evaporation, or conversion of liquid on the skin to vapor. This accounts to 20% of heat loss through sweating and respiration.
4. Radiation is the primary method of heat loss, accounting for about 65% of the body’s heat loss.
Freezing Cold Injuries
Occur whenever the air temperature is below freezing. Frostnip – caused when water on the
skin surface freezes
It is the first sign of impending
Frostbite – happens only in below-
freezing temperatures.
frostbite.
Tissue is damaged in two ways
1.
2.
Actual tissue freezing.
The obstruction of blood supply to the tissue Recognizing
Frostnip
Frostbite
Skin appears red and sometimes
swollen
Painful but usually no further damage after rewarming
Repeated frostnip in the same spot can dry the skin, causing
B Y: G E N E S I S P O N C E
How Cold Affects The Body
The body tries to maintain body temperature by
vasoconstriction and shivering.
Shivering is the body’s main involuntary defense against the cold producing body heat by forcing muscles to contract and relax rapidly. Vasoconstriction is the tightening of blood vessels
Vasoconstriction occurs in the uncovered skin when it is exposed to cold temperatures.
The reduced blood flow in the skin conserves body heat but can lead to discomfort, numbness, loss of dexterity in the hands and fingers. How The Body Produces Heat
Normal body temperature is maintained by a
balance of heat production and heat loss
Heat is produced by food metabolism and
muscle activity.
Shivering increases heat production up to 500%
lack of food limits the body’s ability to
produce heat.
Heat Loss From The Body
Body heat can be lost by four mechanisms.
1. Convection is the loss of heat from the body by air blowing over the skin or through clothing.
2. Conduction, or direct contact with a colder object.
For example, lying in snow but with the exception of being immersed in cold water; Heat is then lost 25 to 30 times faster.
3. Evaporation, or conversion of liquid on the skin to vapor. This accounts to 20% of heat loss through sweating and respiration.
4. Radiation is the primary method of heat loss, accounting for about 65% of the body’s heat loss.
Freezing Cold Injuries
Occur whenever the air temperature is below freezing. Frostnip – caused when water on the
skin surface freezes
It is the first sign of impending
Frostbite – happens only in below-
freezing temperatures.
frostbite.
Tissue is damaged in two ways
1.
2.
Actual tissue freezing.
The obstruction of blood supply to the tissue Recognizing
Frostnip
Frostbite
Skin appears red and sometimes
swollen
Painful but usually no further damage after rewarming
Repeated frostnip in the same spot can dry the skin, causing