News You Can Use: Heat and Vulnerable Populations

“We don’t sweat as much as we get older, and the blood vessels in our skin that are responsible for dilating and exposing more blood to our skin to cool off when it gets hot don’t work quite as well. Older adults also take a lot of medications, on average 8 to 10 per person. Many medications have an impact on how our bodies handle heat.”

“Older folks are more likely to have mobility or transportation issues, which makes it harder for them to get to a cool place when it’s hot, or they might have some memory and thinking changes so that they don’t recognize the risk and aren’t able to respond appropriately.”

Workers at Risk

Nishad Jayasundara, global environmental health researcher

“Construction workers: You have roofers who might be fixing up your roof. You have agricultural workers. But when you say agricultural workers, there are different kinds of agricultural workers: those who might be doing hard labor versus someone who might be picking strawberries. And then you also have our first responders. Different types of labor activities contribute to different types of heat strain.”

Youth at Risk

Valerie Sabol, clinical nursing professor

“There are a lot of kids who are engaged in outdoor activities, sports, band. They have to become acclimated as they get back into the routine. There are lots of things to be concerned about. Are they drinking enough? Are they getting enough rest and shade?”

“When we’re young, we tend to overestimate our abilities. Everybody is at risk for extreme heat exposure.”

Impact on the Body

Cathleen Colon-Emeric, geriatric medicine specialist

“Heat-related illnesses really exist on a spectrum, from mild dehydration to heat exhaustion to really severe heat stroke, which is a medical emergency. In its most extreme form, severe heat can cause brain swelling with confusion and seizures. It can cause multi-organ system failure, blood-clotting problems, kidney failure, and heart and liver failure. Those issues often require ICU-level care and can have persistent long-term effects on the body.”

Recovery Time

Cathleen Colon-Emeric, geriatric medicine specialist

“There’s a spectrum here. Some folks bounce back very, very quickly. We also see persistent or even permanent effects on some folks.”

“The things we tend to see are the neurologic defects, so balance and memory and speech problems that can last for months. The risk for developing chronic kidney disease, even if your kidneys recover immediately, the risk for future damage is increased about fourfold. And there have been studies that have shown an elevated mortality risk that’s two- to three- fold higher than people who haven’t experienced heat stroke.”

Longer-Term Effects

Nishad Jayasundara, global environmental health researcher

“Exposure that can happen for a couple of hours can affect the kidney in a way that makes that kidney more susceptible or makes it more at risk of developing future kidney disease or chronic kidney disease.”

“We already see this is taking place in certain parts of the world where tropical farming communities are showing increased rates of chronic kidney failure at very young ages, and we see that heat stress is a major factor that contributes to that.”

Other Heat-Related Hazards

Valerie Sabol, clinical nursing professor

“I often tell folks that heat rarely travels alone by itself. So, if there’s extreme heat, we often see poor air quality as well. It’s almost a stacked risk. We see increased levels of ozone formation and ground-level ozone. We see stagnant, polluted air. Often accompanying extreme heat is drought, increased wildfires and wildfire smoke, which travels hundreds of miles.”

“As your body tries to cool, your heart and your lungs are working harder. And if you’re already living with a chronic illness, this makes it much more difficult for you to stay cool and recover.”

Treating Heat-Related Illness

Cathleen Colon-Emeric, geriatric medicine specialist

“Get into a cool location, ideally air conditioning, but at least the shade. If the person’s awake and alert and able to drink safely, make sure that they’re drinking plenty of cool water. Wet the skin.”

“If there are any warning signs at all: ... any confusion, decreased or absent sweating, decreased urine production, or very dark urine. Those would be reasons to call 911 and get the person to medical attention properly.”

Heat Mitigation Strategies

Valerie Sabol, clinical nursing professor

“It’s important to have conversations with their healthcare provider to talk about the medications that they may be on or whether there are certain chronic conditions that they have so they themselves should know if they’re at risk and can empower themselves with tools to be ready before the heat event comes, so you can have a plan in place. Just as we think about trying to stay warm in the winter, what’s the plan? We should have a heat plan as well.”

“For younger people: shade breaks, rest breaks, water breaks. It shouldn’t be up to young people to say, ‘hey, I think I need to have a break.’ That needs to be an automated, built-in part of practice.”

Safety for Outdoor Workers

Nishad Jayasundara, global environmental health researcher

“The first step towards getting there is a real acknowledgment through the workplace that this is a risk. Have a buddy system when you work in the field, for example, to make sure you have a companion who checks on you, and you check on them. Make sure you remind each other about hydration practices.”

“It's also important that there are restroom facilities available for the workers to use because it’s easy to say I’m not going to drink water because I’ll have to take a break and walk all the way back to a restroom that’s far away from my work site. Providing a comfortable environment where workers can have a good night’s sleep, where temperatures enable them to recover from that daytime stress, is critical.”

Measuring Heat

Cathleen Colon-Emeric, geriatric medicine specialist

“We’re all used to the standard heat index that uses air temperature and relative humidity but assumes that you’re in the shade with a light breeze. More recently, we’re encouraging athletes, coaches and employers to use what’s called the wet-bulb globe temperature, which also factors in air temperature and humidity, as well as wind speed and cloud cover. So it gives us a more accurate look at the impact of the weather that day on the body.”

Impact of High Overnight Temperatures

Cathleen Colon-Emeric, geriatric medicine specialist

“Our bodies are master adapters, and we evolved to know how to respond to stress like heat stress. But the prolonged exposure without an opportunity for our bodies to recover can often overwhelm those adaptive systems. I think that’s why it’s so important that we have policies in place that mandate a cool place for particular high-risk folks, like our agricultural workers, to recover at night.”

Community-Level Interventions

Cathleen Colon-Emeric, geriatric medicine specialist

“I love the alerts that we’re getting now on our phones, on the news media for the very high heat index days. I think it’s important for communities to have a trigger for mobilizing social services on very high heat days for their vulnerable populations. Often the United Way or local senior centers will deliver fans or have a list of people who need to have health checks. Cooling centers and having those designated places, both formal and informal, that people can go. Making sure we’re thinking about making it as green as possible and having tree cover, minimizing asphalt, and thinking about the building materials we’re using.”

Planning for the Future

Cathleen Colon-Emeric, geriatric medicine specialist

“We really need to have a heat safety plan as well and know when to trigger it and make sure that we’re implementing it, particularly with our vulnerable adults.”

Nishad Jayasundara, global environmental health researcher

“A lot more localized monitoring can help us get a better sense of who is most likely to be exposed to. Build better monitoring systems to help us better understand communities that are at risk of exposure.”

Valerie Sabol, clinical nursing professor

“The biggest thing is really being aware of what’s happening in your world, like what’s happening outdoors, so that you can have that plan in place and not be caught off guard.”

Learn more about how federal funding supports research that keeps communities safe at Duke Research Saves Lives.