Protect against extreme cold, from head to toe

Millions of Americans will shiver this week when temperatures fall across the Midwest.

Some areas are expecting -65°F with wind chill. The cold and wind are expected to create a 100 degree difference between conditions in Los Angeles and Minneapolis. Going outside will be a challenge, and a dangerous one at that.

Dr. George Chiampa of Northwestern Memorial Hospital Emergency Room in Chicago told ABC News the cold will be "unprecedented” and “dangerous,” adding that "everyone has to be very, very cautious.”

Here’s how to prepare your mind and body, from toe to head, for the debilitating impact of the deep freeze.

Extreme risk: extremities

Risk of frostbite and hypothermia increases rapidly at subzero temperatures. That can mean a high risk of severe injury to fingers, ears, nose and toes. Even when outside for a short time, “minutes count,” Dr. Brian Sayger, chairman of emergency services at Advocate Christ Medical Center in Oak Lawn, Illinois, told ABC News. In extreme cold, the body will lower the amount of warm blood circulating to the extremities to keep internal organs warm. This can lead to tissue damage to parts of the body that aren’t getting full circulation.

The beginning of frostbite? It’s called “frost nip,” characterized by white or gray-colored skin that feels unusually firm or waxy, as well as tingling or numbness, according to the Centers for Disease Control and Prevention (CDC). If you think you’ve gotten the first stages of frostbite, reheat the affected area using lukewarm water, not hot water, Dr. Chiampa says. Seek medical attention if the numbness in fingers and toes doesn’t go away, or if your skin shows new color changes that fail to resolve. “Also do not aggressively rub body parts that may be frozen -- that does more damage,” Sayger adds.

Hypothermia: a full-body problem

Layers of clothes help maintain a “heat envelope” to protect your body. When that isn’t enough protection, the body’s core temperature begins to drop and hypothermia sets in, causing shivering, exhaustion, fumbling hands, memory loss, slurred speech, confusion and drowsiness, according to the CDC.

“Children, primarily, have a larger body surface area compared to adults and are more likely to become hypothermic with less of an ability to compensate,” says Dr. Sayger. While everyone should take extreme caution to protect their skin, special care should be considered for the very young, elderly, people with compromised immune systems or other medical conditions. Medication for high blood pressure, for example, can “impact the heart rate and blood pressure resulting in limited ability to the body to compensate” for hypothermic temperatures.

The easiest fix: stay indoors if you can! If you must be outdoors, in addition to wearing multiple layers, a hat, gloves and good shoes, Sayger recommends that you remove any clothing that becomes wet -- soggy clothes lead to additional heat loss.

The elderly and people with medical conditions

“Those who are at the extremes of age are at the greatest risk as their body have less reserve to compensate,” Sayger says, putting them at risk of heart failure or even hear attack. He adds that diabetes and blood sugar levels can also be impacted by the cold if the body is under stress.

Seek help when necessary.

“Any patient with chest pain, shortness of breath, weakness or signs of dehydration should be seen by their doctor or go to the closest emergency department,” says Sayger.

People must also remember to “stock up on medication they may need for the next few days,” says Sayger. While several stores already offer prescription delivery services directly to your home, delivery services may not be as timely during the severe weather.

And don’t forget about any of your family members or pets that may also require medication refills!

Brain freeze?

A less dangerous but more likely result of severely cold weather: mental well-being.

“Stay hydrated,” to help your body cope with the “stress” of the cold and maintain mental clarity, Dr. Sayger says. Symptoms of depression are more likely when people are forced to stay inside, missing out on sunlight, social interaction, and exercise.

Adults, and particularly children, may become agitated -- it used to be known as cabin fever. Practice mindful eating to avoid overeating or snacking when bored. To combat agitation, try journaling, catching up on cleaning, using a meditation app or exercising at home to help maintain a good mood while the weather outside is brutal.

Don’t forget your family and pets

“Check on those friends and family who are at greater risk for health concerns in these extreme temperatures,” advises Sayger. But also, don’t forget that pets are vulnerable to severe weather and should not be left outside any longer than you or your children.

Dr. Robin Ortiz is a physician in internal medicine and pediatrics and a member of the ABC News Medical Unit.

Alexandra H. Antonioli, Ph.D. is completing her combined M.D./Ph.D. training at the University of Colorado School of Medicine in the Medical Scientist Training Program (M.S.T.P.) and is a member of the ABC News Medical Unit.

Dr. Ortiz and Alex would also like to thank Dr. Elise Heeringa Hart for her contribution.