(CNN) -- Winter weather walloped much of the United States this week, dumping feet of snow in some areas as temperatures were forecast to plunge into negative numbers.
If you are among the 100 million estimated to be affected, it's a good idea to prepare for a power outage.
Here are some tips to stay healthy when the lights go out:
A condition called hypothermia happens when a person's core body temperature goes below 95 degrees F. A rapid loss of body heat, usually because of being in cold water, is called acute hypothermia.
Cold outdoor weather poses risks of subacute hypothermia, when the body can't cope with the cold. And chronic hypothermia happens from ongoing exposure to indoor temperatures below 50 degrees F, according to the Centers for Disease Control and Prevention.
If your home has no heat, you can prevent hypothermia by using blankets, wearing layers of clothing and a hat, and moving around, as body temperature goes up with physical activity. Everyone should also be getting adequate food and liquids.
A person with hypothermia may become less awake and aware as his or her body temperature drops. Give the person warm beverages, but not alcohol or cigarettes. Don't try to warm a person with severe hypothermia using direct heat or hot water, as they will need to be carefully rewarmed and monitored. The CDC also discourages rubbing or massaging the skin.
Drink safe water
Water purification systems may suffer malfunctions because of power outages. You should not brush your teeth, wash or prepare food, wash your hands or make ice or baby formula using contaminated water.
Keeping bottled water around is one solution, as long as you know that it came from a safe source.
The best way to make sure that your water is safe from bacteria and parasites is to boil it; one minute of boiling will kill most of these organisms, says the CDC.
You can also disinfect water yourself by filtering it through a clean cloth, paper towel, or coffee filter, or allowing it to settle. Then, draw off the clear water and disinfect using a household chemical aid such as these:
Unscented liquid household chlorine (5-6%) bleach can be used as follows: 1/8 of a teaspoon can be added for every gallon of clear water, or 1/4 teaspoon of bleach for each gallon of cloudy water. Stir well and let stand for at least 30 minutes before you use it. Disinfected water should be stored in clean containers that have tight covers.
Iodine and chlorine dioxide tablets can also be used as disinfectants -- just follow the manufacturer's instructions.
Managing your medications
The elderly and chronically ill need to take note of their medications when the power goes out.
Insulin and some liquid medications may require cooling, says Dr. David Seaburg, president of the American College of Emergency Physicians. In warm weather, lunch bags containing a cool pack are a good option for those products.
For those facing evacuation, it's important to have a record -- either a piece of paper or a computer accessible file -- with the names and dosage information of your prescription drugs. Ideally, it should be prepared in advance.
For diabetics, a supply of snacks is essential, along with insulin and any other medications, says Dr. David Ross, a Colorado Springs, Colorado, emergency physician who assisted victims of a wildfire last summer.
Ross also suggests that people have an emergency one-month supply of prescription medications, so they will not be caught short-handed.
And Seaburg adds, "If you have a chronic illness or take prescription medications and you are evacuated or choose to go to a community center, make someone aware that you have a medical condition, so they will know what to check for if your behavior seems a little unusual."
Another consideration during a loss of power is for patients with chronic breathing problems.
People who require continuous positive airway pressure, or CPAP, devices for sleep apnea or other sleep issues will need an alternative source of power. There are options available for most machines, including CPAP battery packs, DC power options, marine battery adapters and travel-specific CPAP machines to provide power in the event of an electrical outage.
Keeping food at a healthy temperature may be a challenge during a power loss.
Refrigerators keep dairy products, meat, fish, poultry and eggs at a healthy temperature if they are 40 degrees Fahrenheit or below, according to the U.S. Department of Agriculture. If your power goes out, your refrigerator will stay at the proper temperature for about four hours if it's unopened. Placing ice bags or dry ice will help to maintain healthy cooling.
A full freezer will remain cool for about 48 hours, or for about 24 hours if half full. It's a good idea to have digital thermometers on hand to check the temperature.
Once the thermometer goes above the recommended temperature, avoid eating any dairy products, meat, fish, poultry or eggs. Throw away items that have been compromised.
The USDA suggests keeping a supply of canned and packaged foods that do not require refrigeration. Coolers are a good solution if your power will be on within 24 hours. And knowing where to purchase ice and dry ice is a good way to plan for an emergency.
The Mayo Clinic suggests stocking up on condiments, particularly those that are vinegar-based and have a long shelf life, such as ketchup, mustard and soy sauce.
Keep canned protein such as chicken, salmon, beans and peanut butter on hand, the clinic recommends, and keep boxes of powdered milk or shelf-stable milk cartons handy. Also, don't forget a manual can opener.
Eating out of a can doesn't have to be boring, says Ron Stone, assistant director of nutrition at the Mayo Clinic in Florida.
"There are many options to mix and match from your pantry, and with advance planning and a little creativity, you can provide healthy and delicious meals for your family," Stone says.
Clinic interns have created sample three-day meal plans (PDF) to feed a family of four without the use of power or refrigeration, including desserts and energy bars.
The American Red Cross recommends that you turn off or disconnect any electrical devices that were in use when you lost power. This includes stoves and other kitchen appliances. That's because surges or spikes in power can harm your equipment when the power comes back on.
You can leave one light plugged in, though, so that you know immediately when the electricity works again.
It's a good idea to keep candles around, as well as a flashlight on every floor of your home. A battery-operated radio is also handy.
Are you in the blizzard's path? Send your time-lapse videos and photographs to CNN iReport, but stay safe.
CNN's Ashley Hayes contributed to this report.