According to the National Weather Service, temperatures are rising to dangerous levels in the central and eastern parts of the United States this weekend, bringing a number of record-breaking highs across the country. Between now and Tuesday, more than 85 percent of the lower 48 states will experience temperatures above 90 degrees, while half will see temps above 95.

Experts say climate change is increasing overall hot days in the U.S. every year, but this summer's heat is particularly extreme. Meteorologists blame this weekend's heat wave on a massive, high-pressure heat dome — a trap of hot, ocean air causing dangerously high temps in the central U.S. that, by the weekend, will expand to the Great Lakes states and the east coast.

As of Friday afternoon, the NWS has issued heat advisories and excessive heat warnings in several states, spanning from Kansas and Nebraska to the east coast. Both an advisory and warning mean meteorologists predict the heat index — the "feels like" temperature, or the combined temperature and humidity — will likely result in dangerous conditions. The main difference between advisory and warning is temperature: A heat advisory typically predicts a heat index of 100 or higher for at least two days, while a warning usually means it'll feel like 105 degrees or higher.

What are the dangers associated with heat waves?

Hot weather can take a major toll on health, and in some cases, even lead to death — according to the Centers for Disease Control and Prevention, extreme heat causes more weather-related deaths in the United States than any other weather event combined. The risk for heat-related emergencies is especially high for the elderly, pets, and people with chronic illness, but exposure to prolonged, hot weather can increase anyone's core temperature, leading to dehydration, heat exhaustion, or even heat stroke, which can lead to brain, heart, or kidney failure and tissue damage.

While it's only natural to want to spend time outside on a warm, sunny day — summer only lasts so long — the key is not to overdo it. "We tend to see heatstroke in people who are 'weekend warriors' — people who try to do too much outside on their time off and don't accurately assess the weather or their own limitations," says Amy Barger Stevens, a family medicine physician and vice president of the UT Primary Care Collaborative at the University of Tennessee Medical Center.

How to prevent potentially serious symptoms

To avoid heat exhaustion and heat stroke (and to simply stay as comfortable as possible in the oppressive, hot weather), think preventatively. Barger Stevens recommends dressing in loose, lightweight, and light-colored clothing when outdoors — with as few layers as possible — and preloading with fluids before heading out into the heat.

If you plan to spend extended time outside, especially if you'll be active, always aim for the morning (when the heat index is lowest) and take plenty of breaks, moving indoors or to a shaded area when you're starting to feel overheated. As a general rule, avoid consuming excess caffeine and alcohol, both of which are diuretics and will further dehydrate your body, and replenish with plenty of fluids. Just keep in mind that you might need more than just water to replace what you lose through sweat.

"When we tell people to hydrate, they usually think of just replacing their lost fluids with water," Barger Stevens says. "But since water alone doesn’t have enough sodium and potassium for your bloodstream, you'll want to drink both water and sports drinks with electrolytes."


Another important note: If you're on any medication and plan to spend more than just a few minutes outdoors during a heat advisory or warning, double-check with your doctor that you're not at risk for heat-related health issues. Barger Stevens says antihistamines, diuretics, seizure medications, ADD and ADHD drugs, and anti-hypertensive drugs can affect how the body retains fluid.

The most important thing is to seek medical care if you're experiencing heat-related symptoms. If you start to feel nauseous, lightheaded, confused, or weak, go inside right away and rehydrate. Visit a doctor or your local emergency department immediately if the symptoms don't go away after you return indoors, or if you have a fever of 101 degrees or higher after being outside.

How to help those who may not have shelter or A.C.

For those who don't have access to air conditioning, like low-income or homeless individuals, the risk of health concerns is even higher. To help out in your area, you can donate heat-related items like bottled water, sports drinks, sunscreen, hats, sunglasses, and portable fans to a local shelter. You can also offer these items to homeless people directly, or offer to connect them with a local homeless shelter or cooling shelter.

If you see someone who might be experiencing heat exhaustion, you can also offer to call for help. Symptoms to look out for, according to the Mayo Clinic, are cool, moist skin with goosebumps, heavy sweating, dizziness, fatigue, a pulse that's weak or rapid, muscle cramps, nausea, and headache.

Stay cool, stay hydrated, and look out for each other.

Read more stories about summer wellness:

Now, learn all about the eight best sunscreens for summer:

Don't forget to follow Allure on Instagram and Twitter.