These extreme temperatures can have a devastating impact on the Earth, as we’ve recently seen in portions of the Western U.S., where firefighters are struggling to gain ground on several wildfires fueled by soaring temperatures and related drought conditions.
As for humans, when summer’s heat is at its peak, the sweat can start to pour from every pore — or in some cases, put your life at risk. With that in mind, here are five dangerous effects of extreme heat that you should know about:
Your body starts acting weird
The human body has an internal temperature of around 98.6oF, and it does not like it when that very specific figure wobbles in either direction. Changes of as little as a single degree can cause your body’s delicate biochemistry to glitch in some very unpleasant ways.
You’d think that prolonged exposure to heat and humidity would have straightforward effects (you’ll read more about heat exhaustion and heat stroke down below), but sometimes the resulting malfunctions can take some odd forms.
Ever had a muscle cramp on a really hot day, say, while doing some heavy lifting? There’s a good chance the temperature is to blame.
What’s happened is that you’ve sweated out a lot of water, but even if you’ve been drinking water to replace it, you’re not getting enough electrolytes. The resulting salt imbalance is what’s causing the cramps.
For people really not used to the heat, there’s a risk of heat edema. To avoid overheating, your body dilates your blood vessels in an effort to radiate as much heat away from your system as possible, causing blood to pool in your ankles.
Even sweating can sometimes not go as it’s supposed to. If you develop tiny red spots on your skin, with a prickly sensation, that’s a heat rash, caused when your sweat pores become blocked.
And according to the U.S. Centers for Disease Control and Prevention, if you are exposed to extreme heat for a prolonged period, you may stop sweating altogether, a step on the road to potentially fatal heat stroke.
Before you get there, however, the extreme heat will do some unpleasant things to your head as well.
Your brain doesn’t work right
In 2014, Canadian tennis pro Frank Dancevic had a rather unusual court invasion.
Like the other players at the Australian Open in Melbourne, he was struggling through a set in record heat, which became so overwhelming he apparently started seeing cartoon characters.
“I was dizzy from the middle of the first set and then I saw Snoopy and I thought, ‘Wow Snoopy, that’s weird,'” Dancevic said, according to Slate Magazine. “I couldn’t keep my balance anymore and I leaned over the fence and when I woke up people were all around me.”
Confusion and dizziness are common effects of too much exposure to extreme heat, thanks to increased blood flow to dilated blood vessels and fluid loss through sweating.
It’s a real hazard for workers who need to keep their concentration in such conditions. The U.S. Occupational Health and Safety Administration (OSHA) says aside from increased confusion and/or irritability, you may start losing the ability to do skilled or mental tasks.
As for Dancevic’s loss of consciousness, that was potentially something called heat syncope, a temporary drop in blood flow to the brain which occurs when you’ve lost a lot of body fluid due to sweating and low blood pressure.
That could also have accounted for the dizziness too, but given his prolonged exposure, it was just as likely heat exhaustion.
Heat exhaustion sets in
So far we’ve talked about the strange little symptoms of excessive heat, like heat rashes and blood pooling in the ankles. Heat exhaustion is when you’ve lost enough body fluids and salt that the body starts losing its ability to cope.
As your core temperature rises further above the body’s natural 98.6oF sweet spot, your sweating gets heavier, your thirst becomes intense, your dizziness increases and you feel increasingly fatigued.
Your nausea may reach the point you start to vomit, and diarrhea may set in. Those muscle cramps we talked about earlier may happen more frequently, you’ll experience palpitations, and tingling or numbness of the hands or feet.
You may not feel all of these at once, but even a couple of these symptoms in either yourself or a companion should be enough to raise the alarm.
If you experience these symptoms, the CDC recommends taking the following actions:
- Get medical aid. Stay with the person until help arrives.
- Move to a cooler, shaded location.
- Remove as many clothes as possible (including socks and shoes).
- Apply cool, wet cloths or ice to head, face or neck. Spray with cool water.
- Encourage the person to drink water, clear juice, or a sports drink.
And you’d better do it fast. Without treatment, the sufferer may find themselves in the grip of potentially deadly heat stroke.
Heat stroke takes you to death’s door
If you think you’re seeing signs of full-fledged heat stroke, all medical authorities say to call 911. It is that serious.
If someone is at the stage of heat stroke, their core temperature is at 104oF or greater, and their body’s mechanisms for handling the heat have failed. That can include the loss of so much body fluid that sweating stops altogether (although that does not occur in all cases).
Heat stroke shares some symptoms with heat exhaustion, but the most acute to watch out for (according to the CDC) are:
- Hot, dry skin or profuse sweating
- Loss of consciousness.
- Very high body temperature
It can follow on from untreated heat exhaustion, or it can happen without little or no warning.
While you’re waiting for medical help to arrive, the victim has to be moved to a cool, shaded place and have as many clothes removed as possible. Cold cloths or ice should be applied, but the CDC says not to try force the person to drink liquids.
And all of this has to be done quickly. The American Academy of Family Physician says heat stroke has a mortality rate of about 10 percent, but immediate treatment greatly improves survival chances.
Heat waves can kill thousands
When officials decide whether or not to issue a heat warning, Europe’s summer of 2003 can’t be far from their minds.
In August of that year, a stubborn area of high pressure parked itself over a large chunk of the continent, sending temperatures soaring to record levels for weeks at a time.
The result: An estimated 70,000 people lost their lives, with 15,000 in Paris alone.
Cities under heat warnings urge people to check on the elderly, and they were the ones who suffered the most in Europe. According to Live Science, many of the dead were elderly women living in the upper floors of poorly ventilated apartment buildings. Heat would have risen via convection, making it hotter and hotter.
In the United States, more than 600 people die every year due to extreme heat, according to the Centers for Disease Control. In the 1995 Chicago heat wave, almost 700 people lost their lives, and thousands went to the emergency room.
It can be hard to get exact numbers however, as often the bodies are discovered after the extreme heat has subsided, making it difficult to ascribe temperature as the main cause of death.
Still, even though the numbers may be fuzzy, the effects of extreme heat aren’t: If you don’t take it seriously, it can kill.