Take it from an ER doc: 'Don't challenge nature'

If you won't listen to your mother or the meteorologist that this week's deadly temperatures demand great caution, take it from an emergency room doctor.

"When it gets this cold, nobody should be outside unless it is absolutely imperative for them to be outside," said Dr. Douglas Brunette of Hennepin Healthcare. "It'll last just a few days.

"Stay inside," he said. "Don't challenge nature."

But getting to work, walking the dog or shoveling the snow are necessary for most of us, here are some best practices for keeping safe, keeping warm and keeping vehicles running during the polar vortex.

This cold is deathly dangerous for people

Emergency visits for cold-related illnesses like frostbite and hypothermia spike when the temperatures plunge, Brunette said.

Often, he said, people will venture outside, unprepared for the elements — or they just stay out too long.

"Without proper clothing on your hands and your feet and your head and ears, it can be a matter of minutes before you start to get frostbitten," Brunette said.

For example, if the wind chill is at minus 42, frostbite can set in after 10 minutes in the cold, according to the National Weather Service.

The doctor said it's crucial to bundle up your entire body. When it's bitter cold with a high windchill factor, any exposed skin is subject to frostbite, he said. "If everything's covered except your nose, your nose can get frostbitten."

Hypothermia is also a risk. It happens when you body loses heat faster than it can produce it, according to the Mayo Clinic, causing body temperature to drop to dangerous levels.

Brunette said dressing in layers is key to fend off hypothermia. Wool is the best natural material for keeping toasty, he said, but many synthetic materials are good, too.

If you must go outside, Brunette said it's best not to go alone. Part of the nasty weather is that fewer people are out and about. If an emergency happens, you're less likely to find help from someone passing by.

"If you slip and fall and break your ankle and no one's around to help you," he said, "you're going to be in trouble."

Take care of your car

Keeping up with basic vehicle maintenance is key to keeping your car running in the cold, said Nick Stoffel of Lloyd's Automotive in St. Paul. But there are some other ways to give your car some extra help.

• Check the antifreeze and battery. While that should be routine maintenance, Stoffel said, many people skip until cold weather exposes problems. (If you've lapsed on car care and are concerned, Stoffel advises you get to a professional quick.)

• Fill up your tires, now. Cold air causes tires to lose their air pressure — about 1 psi per 10 degrees, according to industry estimates — so Stoffel said people need to keep an eye on their levels.

• Gas up. The fuller the tank, the less chance of moisture forming and freezing inside the fuel line, according to AAA.

• Electric vehicle owners: your car's range may be shorter than normal. Battery capacity is typically reduced in the cold, Stoffel said, and turning on the heat in your car uses up even more of the juice.

Common cold-weather hacks like block heaters or starting your car early aren't always necessary, Stoffel said.

Block heaters, which keep engines warm, or battery warmers may not be necessary, he said. But they can add a little resilience for a cold-weather car. "Any little bit you can do can help," he said. (For what it's worth, a lifelong mechanic from Warroad does recommend a block heater.)

And starting your car ahead of time doesn't help the engine — Stoffel said it's just good for people who want to get into a warmer car.

The engine itself is good to go shortly after it starts, he said.

"Once that oil becomes more fluid as the engine's cranking and spinning," he said, "the pump is circulating the oil, in a few moments, it's fine."