With a heat dome causing extreme temperatures across much of the central and eastern U.S. this week, it's crucial to know how to protect yourself from heat-related illnesses like heat stroke. 

Temperatures are expected to soar above 100°F in many areas, including Washington, D.C., Baltimore, Philadelphia, and New York, with Boston and Portland, Maine, seeing slightly cooler but still hot conditions.

The worst of the heat will hit the Northeast until Tuesday, with some relief by Thursday. However, areas like the mid-Mississippi and Ohio valleys, the Mid-Atlantic, and the Appalachians will likely stay hot for the rest of the week.

Experts warn that this kind of long-lasting extreme heat can be dangerous, especially for those without air conditioning or who spend a lot of time outdoors. 

About 700 people die each year in the United States from heat-related illnesses.

Here's what you can do to stay safe:

Stay Indoors and Cool

Extreme heat puts a lot of stress on your body, which can lead to dehydration, exhaustion, and even deadly heat stroke (when your body temperature reaches 104°F or higher). That's why it’s so important to stay as cool as possible during these hot periods.

If you don't have air conditioning at home, or if your power goes out, look for cooling centres. These are public places like libraries, community centres, or schools set up to offer relief during extreme heat. 

You can find information on how to locate these in your area through the National Center for Healthy Housing. You can also visit other air-conditioned places like local malls, movie theaters, or museums.

Stay Hydrated – Beyond Just Water

Drinking water is essential, but it might not be enough on its own to keep you fully hydrated. When you sweat, you lose more than just water; you also lose electrolytes key minerals like sodium, potassium, and magnesium. 

These electrolytes help your body absorb and hold onto fluids, and they support muscle and nerve function. 

If you don't replace these minerals, you can still become dehydrated, no matter how much water you drink. 

In fact, without electrolytes, that water might just pass right through you.

While you typically get enough electrolytes from food on a normal day, adding an electrolyte packet to your water bottle when you're outside in extreme heat is a great way to prevent dehydration. 

You can also eat more electrolyte-rich foods like bananas, leafy greens, avocados, and salted nuts.

Remember to avoid drinks that will make you more dehydrated, like alcohol (even that icy margarita!) and caffeine. Caffeine can stimulate your body and make you feel warmer.

Protect Your Skin

Hot, sunny days mean your skin is also at risk. While staying indoors is best to avoid the sun's rays during extreme heat, if you have to go outside, take steps to protect your skin.

Sunscreen is a must. Apply it generously to all exposed skin, including your hands and the top of your head. 

Choose a broad-spectrum, water-resistant sunscreen with an SPF of 30 or higher, and reapply it every two hours, or more often if you're swimming or sweating a lot.

Also, consider sun-protective clothing like wide-brimmed hats, long-sleeved shirts made from UPF-rated fabric, and lightweight pants that cover your skin without trapping heat. 

And don't forget your eyes: UV-blocking sunglasses protect against sun damage that can lead to cataracts over time.

Learn the Signs of Heat Illness

It's vital to know the signs of heat exhaustion, which can come on suddenly or gradually.

According to the Mayo Clinic, symptoms include heavy sweating, cool and moist skin (sometimes with goosebumps), fatigue, dizziness, and faintness. 

A person might also have a fast, weak pulse, low blood pressure when standing up, muscle cramps, nausea, and headaches.

These signs mean your body is struggling to control its temperature and needs immediate attention to prevent heat stroke. 

Heat stroke occurs when your body's internal temperature reaches 104°F or higher, and it can cause life-threatening damage to your kidneys, brain, heart, and muscles.

If someone shows these symptoms, first move them to a cool place to rest and give them water and an electrolyte-rich drink. 

If symptoms don't improve within an hour, or if the person loses consciousness, starts vomiting, or experiencessevere dizziness, confusion, or changes in their mental state, call 911 immediately.