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Public Radio's Environmental News Magazine (follow us on Google News)

Stay Safe in Summer Heat

Air Date: Week of

Stay hydrated! Water and electrolyte drinks can help you fend off the heat. (Photo: Sue Thompson, Flickr, CC BY-ND 2.0)

Heat waves can bring health problems and death for anyone but especially for the young, elderly, and people with conditions like heart disease and diabetes. And heat often coincides with other health-harming climate impacts like floods and wildfires. Dr. Ari Bernstein directs the National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry at the CDC and joins Host Aynsley O’Neill to talk about the public health risks posed by heat and share tips for staying safe this summer.


DOERING: It’s Living on Earth, I’m Jenni Doering.

O’NEILL: And I’m Aynsley O’Neill.

This summer is gearing up to be one of the hottest, if not the hottest ever in recorded history. And with people already perishing in extreme heat, we all need to prepare ourselves and our communities for the scorching months and years ahead. Keeping us safe in this increasingly hot and dangerous world is one of the key concerns of Dr. Ari Bernstein. He’s the Director of the National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry at the CDC. And he joins us now. Welcome back to Living on Earth, Dr. Bernstein!

BERNSTEIN: Great to be with you, Aynsley.

O'NEILL: Now, this recent heatwave has been affecting approximately 100 million people across 27 states. How would you link such an extreme event to climate change?

BERNSTEIN: Well, anyone who's been living in the same part of the country for a couple of decades will tell you, it's getting hotter. I mean, we've gotten to the point where warming is evidenced in communities around the country. One way to think about it is, there's always variation in temperature from year to year. We had an El Nino that made things particularly warm last summe, it's contributing probably a bit, although it's reversing now. But you can sort of think of a person dribbling a basketball, and the basketball going up and down as sort of the variability we see in weather from year to year. But we're now dribbling up an incline. And that's the warming of the planet as a whole. And so whatever lows, low temperature years on average we have are now at a higher baseline. And the higher temperatures as we can so clearly see, are beyond what anyone is used to in the places that people have been living for a while.

Aaron Bernstein, MD serves as Director of the National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry at the Centers for Disease Control and Prevention. (Photo: Courtesy of Harvard T H Chan School for Public Health)

O'NEILL: And could you delve into the effects of these record-breaking high temperatures both for the individual person but also for our communities?

BERNSTEIN: Heat can be radically misunderstood in terms of what it means to people, let alone everything in the world around us. In medical school, when I was taught about heat, it was about so-called heat related illness, which is not sort of anything bad that can happen to health when it gets hot out, it really refers to very specific clinical problems like heatstroke. The evidence is clear though that when it comes to health, heat can be bad for a lot of things. Many, many chronic health conditions, whether it's diabetes, or heart disease, even what we call neurodegenerative disorders, like Parkinson's and Alzheimer's. But the effects of heat on health go way beyond that. So we know that heat affects, for example, learning in childhood, it really can affect how people do on tests. And in some cases, when you're taking like a high stakes test, whether that's the SATs or the Regents exam, the implications of not doing well on those tests is a big deal. Heat can affect how safe it is to work outside and how productive workers can be. We even see effects on people working indoors, and especially in places that may not be adequately air conditioning in terms of injuries, but also mistakes that people might make while working. And the more we look at it, the more we realize heat is not unlike the proverbial straw on the camel's back. So you take an existing challenge we face, whether it's health or economic, and too much heat makes it harder to get over that. And so we're at CDC really focused on trying to prevent what are entirely preventable harms from heat to health. We're really focused on communities and individuals who we know are most at risk. Those are people who have significant chronic medical problems, don't have access to air conditioning, or can't afford it, and people who are socially isolated, among many other factors that we know really can up the risk of heat to health.

O'NEILL: Well, let's talk for a moment about these vulnerable populations: the very old, the very young, the unhoused, the isolated. How does the CDC address this discrepancy?

BERNSTEIN: So our job at CDC is to protect health and improve lives. So we have for many years supported programs in states. And I would say that the best innovations we have in this country around getting to those most at risk communities are happening at the local level, because the pathways to safety, as I like to call them, around heat are really locally best defined. And so we've seen whether that's in Maricopa County, where there's a tremendous challenge with just the extraordinary temperatures, you know, it was over 110 for over a month in Phoenix last year. And they are working tirelessly to figure out how to deal with that challenge to people who lack housing, who have substance use disorders in particular. So one of our primary responsibilities is how can we best spur innovation and support the activities at local levels that are really focused on that. We also released on Earth Day this year, the first of its kind health-based heat forecast. This is transformative because up until now, the heads up we got about heat were the National Weather Service's heat alerts and heat warnings. Those were based on percentiles of temperature in specific parts of the country, but they weren't tied to health outcomes. They also tended to be given relatively close to when the heat event started so maybe two three days. The new tool which we call heat risk, is able to give a seven day forecast that is health based, meaning when you go up in increment on the scale and there are four levels there's green, yellow, orange, magenta. As you go up one level in that, it specifically means in that county, that there has been observed increase in health effects from that increment. So it does two things right away. One is it gives you more lead time, right. So you now have got more time to think ahead and plan. And the second is, it enables individuals and communities to really think carefully about, you know, hey, many folks in our community are going to be totally fine on a yellow day. You know, it's nice to know that it might be hotter than usual that there is some actual health effect here, but most people are okay. There may be some people who are not though. And we can start sort of targeting interventions in those at-risk communities on those days. So too, with orange. Pretty much everybody's going to start having trouble with too much heat exposure on a red day and magenta days, as we saw in this country, in the past weeks, are really dangerous for pretty much everybody. And so that incremental piece is critical, because we also know from evidence that the heat alerts that are given by the National Weather Service are given at temperatures well above those that we know, a large share of those people most at risk are already getting sick below those temperatures. So I think the heat risk tool, which you can find at cdc.gov/heat risk is a huge step forward to enabling the interventions that I mentioned at the local level, that are really innovating ways to find pathways to safety.

Philadelphia residents seeking refuge in the shade of Rittenhouse Square Park on a hot June day. (Photo: Shanzay Asif)

O’NEILL: And what are sort of the individual steps that someone should take when it comes to dealing with the heat? Is it simply hoping you can find a nice air conditioned space and a cool glass of lemonade? What does someone do in that situation?

BERNSTEIN: So we have a mantra: “Stay cool, Stay hydrated, Know the symptoms.” So staying cool could mean anything from using a fan, and fans can be remarkably effective. We know that if things are getting super hot, they can be counterproductive. We generally suggest that fan use is helpful well into the 90s. But you know above that you can run into situations where heat, you know, like a convection oven, the fan can actually increase heat absorption into the body. But fans are really good, shady spots and parks can be immensely cooler. And of course, even going, if you're in a multi story building down a few levels, you know, to a neighbor's place can be cooler too. Then, of course, there's air conditioning with the main challenge being it's expensive. And during these recent heat waves, we had power outages. And so relying solely on air conditioning, again, thinking about the folks who have the hardest challenge in accessing air conditioning, we obviously need it. But we need to think about the layers of protection we can put in before we are wholly reliant on air conditioning. And unfortunately, there are more and more days when you need AC. So that's the “Stay cool” piece. And in our work, we're really focused on what works for that individual. That could be AC, it could be that shady place in a park, and whatever is going to be accessible and effective. Stay hydrated. Drink water, first and foremost. There are a lot of beverages that people tend to pound that may not be so helpful, caffeinated beverages, sugar sweetened beverages, alcohol may all promote dehydration. So we tend to advise going for water. People with kidney disease or heart disease may need to be more careful because their bodies are more fluid sensitive. And that's really important for them to discuss with their providers, which again is a key part of our guidance that we have given that ties into heat risk. So we have specific guidance for people with, for example, cardiovascular disease, that tries to get people to have proactive conversations with providers saying "Hey, it's super hot out. What should I be thinking about with hydration?" We know that our bodies can tell us when we're well hydrated. Our mouths are wet inside, our urine is clear, if not maybe a little bit yellow. If it gets dark yellow, it’s, body's telling us we're not as well hydrated. And then know the symptoms is critical as a sort of third piece of the mantra because if you think you're staying cool, and you're trying to stay hydrated, but your body's telling you things, you need to listen. And depending upon who you are, those may appear differently. For people with chronic conditions like diabetes, when you get dehydrated or overheated, your blood sugar's not going to be well controlled, it’s gonna be harder to control. People with heart disease may start to experience the symptoms of their heart disease. And though those are symptoms for certain diseases, a lot of people independent of that who are otherwise healthy, they may feel nauseous, they may get headaches, their skin may get really warm, red, may start having a lot of sweat or even no sweat. There are common symptoms of your body getting overheated. And those are important because that's when you need to take a step back and saying, if possible, and one of the things we clearly recognize is that not everyone can get themselves to safety with heat. But to the extent possible, that's time you need to try and take a break, go someplace cool off, even for an hour or two can make a huge difference in terms of risk. And so knowing the symptoms is really a critical third part of that mantra.

O’NEILL: Well, climate change linked extreme heat is only going to get more intense in coming decades. And on top of high temperatures, there's also ties to other climate disruption, like forest fires or deteriorating air quality, flooding even in some parts of the United States. So how do you sort of approach a full perspective on that?

BERNSTEIN: We are aware of concurrent health challenges from extreme events like heat, and fires or heat and floods. We've already seen heat and floods in Florida this year. Last summer, we had heat and wildfire smoke across huge parts of the country. So we see the reality that is these events are happening at the same time. And our guidance is picking up on that. So if you go to our dashboard on heat, cdc.gov/heat risk, on the front page, we have the heat risk forecast, we also have the air quality index, because many of the low cost easy wins around heat, whether that's opening windows, or other measures may not be the best choice if there is a lot of air pollution. Especially for conditions that are really sensitive to that, like asthma or heart disease. So we are moving into an integrated approach to these risks. And we have already a tremendous amount of resources around flooding. And we're integrating that with heat because we see these things concurrently. And the recommendations may be different. In flooding situations, one of the two most common challenges are no power and no water. Well, the traditional heat response requires air conditioning and cooling off by taking a cool shower. Well, if you don't have water, and you don't have electricity, those two things may be hard to do. And so we need to think differently about how to keep people cool in the event that you're dealing with flood and heat concurrently is one example. And similar considerations for heat and wildfire smoke, which is another relatively common concurrent event. And so we're really focused on working again with communities around the country to figure out how we can do better in preventing what is wholly preventable harm from heat. I am certainly committed to that in our work at CDC and I know our partners in states around the country are as well.

O'NEILL: Dr. Ari Bernstein is the director of CDC's National Center for Environmental Health, and the Agency for Toxic Substances and Disease Registry. Dr. Bernstein, thank you so much for taking the time with me today.

BERNSTEIN: Great to be with you.



The CDC’s HeatRisk tool

The CDC’s Heat and Health Index

CDC’s heat guidance can be found here


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