Hypothermia

A drop in body temperature below

95 degrees. A severe case would be

86 degrees or lower. When core

temperature drops, the brain’s

hypothalamus (our built-in thermostat)

triggers several reactions:

Mild

Severe

Muscles shiver to produce heat.

Blood vessels in skin and extremities

constrict to concentrate warm blood

around the core.

Slurred speech

Drowsiness, confusion, loss of

coordination, loss of consciousness.

HYPOTHALAMUS

To preserve

skin tissue,

blood vessels

periodically

dilate at the

surface,

giving

us rosy

cheeks.

Heart rate

drops,

breathing

becomes

shallow.

HEART

LUNGS

Goose bumps

raise hairs to trap

air for insulation — great

for furry mammals but useless to us.

What to do

• Get out of the wind.

• Replace wet clothes with warm, dry clothes

and blankets.

• Drink warm beverages without caffeine or

alcohol.

• Be careful with electric blankets and hot

packs — they can burn.

• Call 911 if a person is unconscious.

Who is at greatest risk?

The young and the old

Weak bodies can’t fight off cold as well as

healthy ones. Diabetics may not feel the

onset of frostbite. Cold air can trigger

asthma attacks and other respiratory

problems.

Drinkers

Alcohol dilates blood vessels at the skin

surface, allowing more heat than usual to

escape. It also contributes to dehydration,

which can occur faster in cold, dry air.

People who work or exercise outside

Wind and moisture, even from sweat,

accelerate heat loss. Anyone who spends a

lot of time outside should dress in layers

and cover as much skin as possible.

Frostbite

(and the lesser frostnip)

Damage to skin and other tissues from

freezing. Face, ears, fingers and toes are

most vulnerable. Because less blood is

flowing to the skin and extremities, they

can freeze faster.

Frostnip

Pain, itching, numbness

Skin turns white, gray or yellow

Fingers lose dexterity

Ice crystals form in and around cells, which

causes damage and clotting. Nerve impulses

and muscles slow.

Frostbite

Skin feels hard, stiff or waxy

Purple or black blisters may appear

Gangrene can set in

Blood can’t reach oxygen-starved tissue, and

cells begin to die. If muscles, tendons and

nerves freeze, amputation may be required.

Frostbite

Frostnip

Healthy

What to do

• Replace wet clothes with warm, dry clothes

and blankets.

• Warming should be gradual, with warm (not

hot) water until color returns.

• Don’t rub—that can cause more damage.

• If a person has severe frostbite, get

immediate medical attention.

Hypothermia

A drop in body temperature below 95 degrees. A severe case would be 86 degrees

or lower. When core temperature drops, the brain’s hypothalamus (our built-in

thermostat) triggers several reactions:

Mild

Severe

Drowsiness,

confusion, loss of

coordination, loss

of consciousness.

HYPOTHALAMUS

Blood vessels in skin

and extremities

constrict to

concentrate warm

blood around the

core.

Slurred speech

Muscles shiver

To preserve skin

to produce heat.

tissue, blood

vessels periodi

-

cally dilate at the

surface, giving us

rosy cheeks.

Heart rate drops,

breathing becomes

shallow.

HEART

LUNGS

Goose bumps

raise hairs to trap

air for insulation — great

for furry mammals but useless to us.

What to do

• Get out of the wind.

• Replace wet clothes with warm, dry clothes and blankets.

• Drink warm beverages without caffeine or alcohol.

• Be careful with electric blankets and hot packs — they can burn.

• Call 911 if a person is unconscious.

Who is at greatest risk?

The young and the old

Weak bodies can’t fight off cold as well as healthy ones. Diabetics may not feel the

onset of frostbite. Cold air can trigger asthma attacks and other respiratory problems.

Drinkers

Alcohol dilates blood vessels at the skin surface, allowing more heat than usual to

escape. It also contributes to dehydration, which can occur faster in cold, dry air.

People who work or exercise outside

Wind and moisture, even from sweat, accelerate heat loss. Anyone who spends a lot

of time outside should dress in layers and cover as much skin as possible.

Frostbite

(or its little brother, frostnip)

Damage to skin and other tissues from freezing. Face, ears, fingers and toes are

most vulnerable. Because less blood is flowing to the skin and extremities,

they can freeze faster.

Frostnip

Frostbite

Pain, itching, numbness

Skin feels hard, stiff or waxy

Skin turns white, gray or yellow

Purple or black blisters may appear

Fingers lose dexterity

Gangrene can set in

Ice crystals form in and around cells, which

Blood can’t reach oxygen-starved tissue, and

causes damage and clotting. Nerve impulses

cells begin to die. If muscles, tendons and

and muscles slow.

nerves freeze, amputation may be required.

Frostbite

Frostnip

Healthy

What to do

• Replace wet clothes with warm, dry clothes and blankets.

• Warming should be gradual, with warm (not hot) water until color returns.

• Don’t rub—that can cause more damage.

• If a person has severe frostbite, get immediate medical attention.

SOURCE: Sources: U.S. National Library of Medicine, Baylor University Medical Center, Centers for Disease Control and Prevention, Medical News Today, WebMD. GRAPHIC: Bonnie Berkowitz, Patterson Clark and Katie Park - The Washington Post. Published Jan. 21, 2016.