Heat dome brings triple-digit temperatures: Why overheating kills and how to recognize the signs – CNET


Keep yourself cool and hydrated during heat waves.

James Martin/CNET

The US experienced its hottest June on record this year, and the news isn’t getting any better. This weekend, triple-digit temperatures are expected to affect up to a dozen states in the Western region, including Montana and Idaho — where the average high temperatures in July are between 75 and 88 degrees in Montana and between 79 and 95 degrees in Idaho. Montana is under an excessive heat warning from Saturday to Thursday. Overheating wreaks havoc on human bodies, with fainting, dangerous dehydration and even sudden deaths triggered by extreme temperatures. 

Record heat waves are on the rise, partly due to human-induced climate change triggered by the burning of fossil fuels. The death toll rates increased in the US and Canada last month, with 107 deaths reported after Portland reached a record-breaking temperature of 117 degrees.

The best way to protect yourself and high-risk loved ones from heat stroke, and worse, is to know the signs of dangerous overheating, and how to help prevent them. Here are practical tips from experts I spoke with and the Centers for Disease Control and Prevention.

Read more: Heat wave in US and Canada summed up in one staggering satellite image

How are high temperatures dangerous to people?

When a person overheats, their body temperature could rise to 103 degrees or higher because their internal temperature control system is overloaded and can’t cool down fast enough. The typical healthy temperature range for babies and adults is under 100 degrees Fahrenheit. A temperature over 100 degrees can cause hospitalization in babies and adults. Sweating isn’t always enough to rapidly cool the body and keep it from cooking. Extremely high body temperature can lead to heat stroke and damage the brain — it can also cause death.

“The body has an intrinsic ability to adapt to high temperatures, but we worry when high-risk people are in the heat for an extended period of time because their body may not compensate as well,” Dr. Matthew Levy, associate professor of emergency medicine at Johns Hopkins, told me. 

People may be at higher risk for overheating as a result of the pandemic lockdown, which may have kept people indoors in cooler conditions. With restrictions easing across the world, increased exposure to excessive outdoor heat could take a rapid toll.


Make sure you’re drinking water consistently to avoid dehydration.

Angela Lang/CNET

How does dehydration play a role?

Dehydration throughout the body isn’t as simple as thirst. Up to 60% of the human body is made up of water, which is required to pump nutrients around the body. Without enough, systems can fail, putting you at risk for a medical emergency. 

It isn’t always easy or possible for people to adequately judge how much water and electrolytes they actually need in extreme heat, Levy said.

Mild dehydration can often be treated by getting out of the sun, drinking water and taking in electrolytes. More severe dehydration may require medical intervention, like a hydration drip that contains electrolytes.

There have been heat waves before. Why are experts worried now?

Any time heat waves occur, they can be worrisome — especially when there’s a sudden rise in temperature or shift in weather patterns in areas of the country where people aren’t accustomed to extreme heat.

Experts are concerned that in those areas that have been most impacted — such as Seattle and Vancouver, British Columbia — many of those houses aren’t equipped with air conditioning, director of national climate assessment at National Oceanic and Atmospheric Administration David Easterling said in an email. 

It isn’t just the high temperatures during the day causing bodies to dangerously overheat. If nighttime temperatures remain high outdoors and inside, human bodies may not be able to adequately cool off, which can cause heavy sweating, nausea, headaches and even death (see below). This June broke more nighttime temperature records than any previous June.

While heat waves have happened before, they also may be more severe due to climate changes caused by humans, Easterling said. When people burn fossil fuels, it increases greenhouse gas emissions, which have been linked to the increasing frequency of extreme heat. The heat waves are becoming more severe and more likely to happen due to the climate crisis.

Who’s at the highest risk of heat-related death and why?

While some people can handle excessive heat better than others, some people are inherently vulnerable to extreme heat, according to the CDC. 

  • Adults over the age of 65 because they don’t adjust as well as young people to sudden changes in temperature.
  • Infants and children — especially those left unattended in parked cars.
  • People who work outdoors and who aren’t able to cool off and drink water.
  • People in low-income situations, especially those without appropriate resources for water.
  • People with chronic medical conditions may be less likely to sense and respond to changes in temperature or could be taking medications that make the effects of extreme heat worse.
  • Athletes who exercise or perform in extreme heat during the hottest part of the day.
  • Pets that are left in a car during hot days or that are left outside with limited shade or water.

Keep an eye on your heart rate when you’re exercising or working outdoors.

James Martin/CNET

How do you recognize signs of heat illnesses?

There are five heat-related illnesses to watch out for when someone’s exposed to excessive heat, according to the CDC. Look for these signs.

  • Heat stroke: High body temperature. Hot, red skin. Fast, strong pulse. Headache. Dizziness. Nausea. Confusion. Losing consciousness.
  • Heat exhaustion: Heavy sweating. Cold, pale and clammy skin. Fast, weak pulse. Nausea or vomiting. Muscle cramps. Tiredness or weakness. Dizziness. Headache. Fainting.
  • Heat cramps: Heavy sweating during intense exercise. Muscle pain or spasms.
  • Sunburn: Warm, red skin. Blisters on the skin.
  • Heat rash: Red clusters of small blisters on skin.

What should you do to help if you suspect someone is in danger?

Here are some steps to follow if you suspect someone is in serious danger from the heat, Levy said.

  • Call 911 immediately, especially if the person loses consciousness. 
  • If it’s a life-threatening emergency, like a heat stroke, move them out of heat ASAP and find somewhere cool and shaded — preferably indoors with air conditioning. 
  • If it’s not possible to move them into a cool space, try to move them out of the direct heat and start cooling them. You can do so by wetting their clothes with water and removing any unnecessary layers of clothing.
  • If they’re conscious, give them water or clear fluids with electrolytes to sip.

How can you help prevent heat exhaustion?

Here are some tips from the CDC and Levy for preventing heat-related illnesses.

  • Make sure you have a working air conditioner. If not, find somewhere to go, such as a library, a store or a relative’s house.
  • You can use a fan as a temporary fix. It won’t lower the temperature of the room, but can help cool you off.
  • You should also check on neighbors and family to make sure they’re OK.
  • Wear sunscreen to prevent sunburns, as they can affect your body’s ability to cool down and can make you dehydrated.
  • Alter your routine so you aren’t outdoors during the hottest point of day — the afternoon. Do outdoor chores or exercise in the morning or evening when it’s cooler.
  • Pace yourself and check for heat-related illness signs if you’re not feeling well. 
  • Feeling a headache or thirst? Drink clear fluids ASAP to prevent from becoming dehydrated. 
  • Alcohol can affect the body’s ability to regulate hydration and can cause you to lose more body fluid, so try to avoid it on extremely hot days. 
  • Avoid hot and heavy foods because they add heat to your body.

For more information about the heat waves, here’s what’s happening in the US and Canada. Also, surface temperatures in Siberia have heated up to 118 degrees and the severe Western drought and heat wave, explained.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.