Hundreds die each year in the U.S. due to excessive heat, according to the CDC.
A heat wave is gripping the U.S., with dangerously high temperatures in the West, South and Northeast. Meanwhile, deadly heat is slamming Europe, with the United Kingdom breaking its record Tuesday for highest temperature ever.
Doctors recommend taking excessive heat warnings seriously. There are hundreds of deaths each year in the U.S. due to excessive heat, according to CDC WONDER, and scientists caution the actual number of heat-related deaths is likely higher.
Here are tips to stay safe from the heat from the Centers for Disease Control and Prevention:
Take precautions to prevent sunburn, which can make you dehydrated and affect your ability to cool down.
Use sunscreen that's SPF 15 or higher 30 minutes before going outside. Sunscreens that say "broad spectrum" or "UVA/UVB protection" are best.
Drink extra fluids, and don't wait until you're thirsty.
Avoid very sugary drinks and alcohol, which can cause your body to lose more fluid, and be wary of extra-cold drinks that may cause stomach cramps.
Avoiding hot and heavy meals also can reduce your body's overall temperature.
Cut down on exercise during heat waves and rest often and in shady areas.
Try to limit your time outside to when it is cooler, like in the early morning and evening.
Never leave children in a parked car -- even if windows are cracked open.
Anyone can suffer from heat-related illness at any time, but these people are at greater risk:
According to the CDC, "heat-related illnesses, like heat exhaustion or heat stroke, happen when the body is not able to properly cool itself. While the body normally cools itself by sweating, during extreme heat, this might not be enough. In these cases, a person's body temperature rises faster than it can cool itself down. This can cause damage to the brain and other vital organs."
Heat stroke is the most severe heat-related illness.
If a person's body temperature rises above 104 degrees Fahrenheit, the result is a heat stroke. When a person has a heat stroke, they are no longer sweating, but their skin is flushed.
Without emergency treatment, the brain, heart, kidneys and muscles can be damaged, and it can even lead to death.
Before someone has a heat stroke, they get overheated and experience heat exhaustion. Heat exhaustion is more common during and after long periods of exercise.
If someone shows symptoms of heat stroke or heat exhaustion, call 911, move them somewhere cooler and use towels to cool down their body.
Here are some tips from the American Society for the Prevention of Cruelty to Animals for how to keep your pets safe in the heat: provide plenty of fresh water so they don't get dehydrated; don't over-exercise pets; never leave pets alone in a parked car; and watch for symptoms of overheating, which include excessive panting, difficulty breathing, increased heart and respiratory rate and drooling.
Animals with flat faces, like pugs, can't pant as well and are more at risk of heat stroke. These pets, as well as older and overweight pets, should be kept inside as much as possible.
ABC Owned TV Stations contributed to this report.