CNN 10｜Heatwaves' body effects, your brain on ChatGPT

Dr. Sanjay Gupta: We begin with millions of people across the United States facing an unprecedented and dangerous heat wave. In fact, Tuesday was the hottest day in over a decade for parts of the East Coast. In the Midwest, some roads in Wisconsin, Iowa, and Missouri were closed. Why? Because they were buckling under the searing heat. 

Meteorologists say this is all because of what is known as a heat dome. That's when a ridge of high pressure builds over an area and then doesn't move for up to a week or more. 

This high pressure can result in lots of sunshine, very few clouds, but that also means sinking air. And when air sinks, it warms, and that causes temperatures to rise even higher. The dome is created because the air simply can't escape. Now, the climate crisis is expected to make heat domes more frequent and even hotter. 

So, what are the effects of these high temperatures on our bodies and on our health, and how can we adapt? CNN senior climate reporter, Lara Paddison, put her body to the test under extreme heat, extreme humidity, to highlight the health dangers of a warming world. 

Lara Paddison: Everything that's going on with my body made that hard. We're here at the University of South Wales in the UK, and behind me here is an environmental chamber where scientists can control the temperature. 

And so they're going to crank the temperatures up to about 40 degrees Celsius, 104 degrees Fahrenheit. And the whole point of this exercise is to see what impact extreme heat has on my body. 

This on my head is measuring brain blood flow. Here is measuring skin temperature on my leg. We're going to be looking at cognitive functions, like how is my decision-making affected by the heat. We need to understand what it's going to be like living in a much hotter world. 

Damian Bailey: Okay, Laura, so you're fully instrumented. You're ready for action, ready for lift-off. 

Laura: It's 40 degrees now, 20% humidity, and I can really feel it starting to sweat. My face is getting very hot. My skin temperature's gone up by a couple of degrees. 
Damian: You're doing a really, really good job here. 

Laura: It's 40 degrees Celsius, but it's 85% humidity, and the difference is intense. It's like a sauna in here. This is really, really tough. Like, hands feel a bit shaky. Everything feels tiring. Even breathing feels weird. 

Damian: Stop. Great job. 

Laura: Thank you. 

Damian: Mission accomplished. So it's not easy. Now, you've got a markedly depressed increase in exercise-induced blood flow to the brain. It's gone from 600 milliliters per minute to 400. 

Laura: That's really significant. 

Damian: Which is huge. You're not getting enough fuel into the brain. You're not burning enough fuel to be able to make the right decisions. You would make potentially wrong decisions, rash decisions, and a much larger increase in pressure during exercise.

So your heart is working a lot, lot harder, probably about 30% harder, just because of that increase in temperature and humidity. 

Ola patients, you know, this is a big de.al for them. and they wouldn't be able to do the simplest tasks, even stand up to get out of a chair. From a cardiovascular perspective, that would just be too demanding. 

Dr. Sanjay Gupta: Now, imagine writing an essay with the help of AI. Maybe some of you have even experimented one of these programs, like ChatGPT. You give it an assignment. You give it a prompt, like, write a book report on to kill a mockingbird. And in just mere seconds, it types out the report. 

It's pretty amazing. And it sounds easy, right? Well, a new study is raising questions about what that could mean for your brain in the long run. 

Researchers at MIT studied three groups of students. One group used ChatGPT to help write their essays. Another used Google's search engine to write the essay. And a third group relied only on their own brains, no tech tools at all. And here's what they found. 

Scientists used brain scans called EEGs And they saw big differences. In fact, the students who didn't use any tools, they showed strong activity in several areas of the brain, including the prefrontal cortex we just talked about, that's responsible for focus and complex learning, but also what is known as the occipital parietal region, which is back here. That's more linked to visual processing and reasoning. 

Now, the Google search group, they showed moderate or intermediate levels of engagement in those same areas. Meanwhile, importantly, the students who used AI showed much weaker brain connections, meaning their brains simply weren't working as hard. 

Now, when some students switched from using AI to writing without it, their brains sort of struggled to re-engage. Others who started using AI suddenly did remember more facts, but weren't able to think as deeply. 

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