Heat ‘Wave’ Is Far More Than That, Duke Experts Say

Experts on health and heat mitigation brief media on Thursday

 Heat ‘Wave’ Is Far More Than That, Duke Experts Say

Here are excerpts:


Ashley Ward, director, Duke’s Heat Policy Innovation Hub

“One of the things we’ve talked about with respect to heat over the years is how difficult it is to capture the public’s attention around heat with comparison to other natural disasters. Heat doesn’t typically give you this camera-ready fodder that really motivates people to move like we see with hurricanes or tornadoes or other severe weather.”

“But this year Mother Nature has shown us in quite spectacular fashion -- through marine heat waves that have sent thousands of dying fish on the shores, particularly on Gulf Coast states, and bleaching our coral reefs. News reports of hikers succumbing to the heat, burn units being filled in places like Arizona with people experiencing critical and sometimes deadly burns from contact with pavement and other sort of structures in our environment.”

“What we’re seeing and what has been reported is nearly 30 days of triple-digit temperatures, breaking not just high temperature records -- breaking the records of daytime temperatures, but also breaking the records of overnight temperatures.”

“We’re continually categorizing this extended period as a heat wave, and I see that reported a lot. At 30 days we’re not talking about a heat wave anymore. We’re talking about a season. We’re talking about a marker, a shift. This is not an acute event. Typically you think about a three to five-day event. We’re talking about a new chronic state of being for heat season. It isn’t unreasonable to think this could quite possibly be the coolest heat season of our lives.”


Dr. J.J. Hoff, emergency medicine specialist

“This summer has been particularly busy. We’ve seen record temperatures that are continuing to climb so we’re seeing a lot of heat-related illnesses.”


Jordan Clark, heat researcher (Read this plan to protect athletes)

“The heat risk for student-athletes is high, simply because of them being a younger population. The critical point here is that it goes from summer to a sudden exposure to extreme heat that also involves doing intense outdoor activities. This all happens to overlap with the most humid and hot part of the summer.”

“There is usually a wide spread in how acclimated to heat each player is. Since some may be working this summer outdoors while others may have spent summer indoors, so there’s a lot of variation there to try to account for form a coach’s perspective.”

“The key ultimately to mitigating this is the gradual increase in activity over time so the body can slowly, steadily get used to it. Our bodies are naturally quite good at adapting to heat exposure.”


Ashley Ward

“Folks who are over 65 who have chronic illnesses, certainly outdoor workers (are very high-risk). But we need to broaden the scope of who is vulnerable and how and why. We focus significantly on the urban heat island affect. Urban populations, how they are vulnerable, when, and what are the appropriate responses.”

“However, in North Carolina and in much of the Southeast … rural heat vulnerability is a significant issue, and it’s not only about farm workers. In North Carolina and throughout the Southeast, for example, manufacturing is located in rural areas. It is not unusual to have indoor manufacturing temperatures to exceed 90 degrees during the day, with populations that return home and live in either energy-inefficient housing or do not have access to adequate or any cooling in their homes. So expanding who we think is vulnerable is an important aspect to this.”

“Also, we need to think about institutionalized populations that often don’t come up in these conversations. Those who are incarcerated, for example. There is no rule requiring that prisons must be air conditioned.”

“Nursing homes and long care facilities -- there is no federal requirement that they are air conditioned, however many states have state-level requirements.”

“Public housing and affordable housing, low-income housing residents, there is no requirement. This is women, children, the disabled. So we really need to think holistically about who is at risk.”


Dr. J.J. Hoff

“It exists on a spectrum. What we’re looking for is evidence that this heat has progressed to create an inflammatory cascade within the body where you’re seeing evidence of organ disfunction. Very often when we’re exposed to heat, you might feel a little bit lightheaded. Very often … we sweat as our body’s natural response to try to cool itself off. If you feel that’s not doing the job or if your skin seems dryer than it should be, especially when you’re in the heat, that’d be time to remove yourself from that exposure and seek shade and seek cooler temperatures and start hydrating.”

“Very often you’ll progress beyond that and see someone acting different or will seem confused. Anytime someone passes out or loses consciousness due to a heat exposure, that’s someone you should call EMS for.”

“The most important thing you can do in that situation is get help and on top of that, get them removed from that exposure. Get to as cool as environment as you can and get hydration on board.”


Jordan Clark

“Most are familiar with the heat index, or a ‘feels like’ temperature, which really accounts for how our body senses the environment based on the temperature and humidity.”

The wet bulb globe temperature takes this a step further. It considers air temperature and humidity but also considers the impact of wind blowing across our bodies and the impact of heat coming from the sun and whatever surface is below us – such as a tennis court versus a grass field.”


Ashley Ward

“It’s a really important aspect to this national conversation we’re having right now. There are certain areas of the country, traditionally in the Western part of the country, where these huge daytime temperatures that we see, in the triple digits, really drive a lot of the health outcomes, and temperatures typically would fall overnight. In those regions of the country, people would open their windows at night, they can cool down their homes, cool down their bodies. Every living being in the environment can cool down and get a reprieve.”

“That’s not exactly what we’re seeing in this heat season. We’ve seen some incredibly dangerous situations … where we’ve had these extreme temperatures during the day but also a failure for the temperature to drop overnight. In Arizona we’ve had several days where it remained above 90 overnight. This is by far one of the most dangerous circumstances where we have both extreme temperatures in each part of the day.”

“In the Southeast, however, we have the added humidity, so even if it’s not in the 115 (-degree range) -- even if it’s 98 with 90 percent or better humidity, we do see really significant health outcomes. It isn’t uncommon in the Southeast for overnight temperatures to remain consistently high -- over 75 degrees overnight.”

“What’s extraordinary about this heat season is we’re seeing, across the Sun Belt region, incredibly high daytime temperatures associated with higher-than-normal rates of humidity and persistently high overnight temperatures. This is in fact the worst-case scenario for health outcomes.”


Dr. J.J. Hoff

“The temperature itself isn’t the only measurement we’re looking for. The temperature the body sees is the most important thing. So we often look of a critical temperature of 95 degrees that a body experiences that sets off that inflammatory cascade. That’s when you see some of the worst results from heat exposure.”

“You don’t have to be outside as an athlete exerting yourself to have a heat-related illness. You can just be exposed to it over a long period of time.”

“If your body for whatever reason is not able to respond … to use sweating and evaporating cooling to cool itself back down to the normal functioning temperature it wants to be at, those organs won’t work as well and you’ll see some of the effects of heat stroke.”


Jordan Clark

“The critical piece here is taking these measurements on site on the field where the activity is occurring. You often see instances where weather conditions from a weather station that may be located two miles away or 20 miles away may being used. The difference between where a given football field is and that given weather station can be quite different.”

“Having direct measurements on site allow for the most robust measurements of how hot is it right here, and what actions can we take to mitigate it.”

“If you’re standing on a tennis court taking a measurement right there, versus standing on a grass field taking the measurement right there, they can be quite different and impact the body in much different ways.”

Four-panel infographic showing: 10% of air temperature + 70% of natural wet bulb temperature + 20% of black globe temperature = Wet Bulb Globe Temperature. Panel 1 image: Thermometer at 85 degrees. Panel 1 text: "Air temperature: What your favorite weather app shows." Panel 2 image: Thermometer at 78 degrees with wind and moisture around bulb. Panel 2 text: "Natural wet bulb temperature: Simulates the cooling effect of sweat." Panel 3 image: Thermometer at 115 degrees with sunlight beaming down on black globe. Panel 3 text: "Black globe temperature: Simulates how hot it feels in direct sunlight." Panel 4 image: Reading of 86.1 degrees. Panel 4 text: "Wet Bulb Globe Temperature: Includes temperature, humidity, wind speed, and sunlight to measure heat stress on the body." Logo at bottom for Nicholas Institute.


Ashley Ward

“I understand that implementing or instituting a national cooling standard would come at considerable effort and cost. We have a standard that buildings be heated during the winter up to a certain level. Landlords are required to provide heating for their tenants; schools are required to have heat; prisons … are protected by this heating standard in the U.S. We do not have a like cooling standard, and this is challenging.”

“The funding for cooling for schools would come out of local budgets. So this potentially would strain considerably the ability for local governments to respond. I say that but I also want to point out that Scotland County in North Carolina, one of the poorest counties in the state, implemented universal air conditioning in their schools. So it is possible to do even on a limited budget.”

“But along with a cooling standard, there needs to be a process through which either funding or innovative financing mechanisms can be deployed to help people comply with such a standard.”


Dr. J.J. Hoff

“First and foremost, hydration, hydration, hydration. People need to stay hydrated. Our body’s response to extreme heat is to sweat, and we lose fluid that way and we need to replace fluid. So we need to stay hydrated.”

“On top of that, one of the more effective cooling mechanisms you can do, honestly, is just a fan. We use the evaporative cooling, using a fan to blow that moisture off your skin. That can help to rapidly cool the body. Fans work relatively well. The most important thing though is getting out of that environment and going to a cooler place.”


Ashley Ward

“A 10-minute cool shower can effectively lower your internal body temperature. If you are in a situation where you lose power and don’t have air conditioning, that’s one way to do it. But even if you have air conditioning … but it’s very warm and your air conditioning can’t keep up and you notice it’s persistently over 80 degrees in your house, taking a cool shower can be extremely effective in lowering your body temperature.”

“Immersing your feet over the ankle in cool water – this works great for our aging population or disabled population – also has the same effect of lowering core body temperature. And then the military did some great work – they don’t want their soldiers taking their boots off all the time, right? – they discovered that arm immersion over the elbow has the same impact as foot immersion over the ankles.”


Dr. J.J. Hoff

“First and foremost, the answer is always water. Start with water.”

“We do occasionally see people who will over-hydrate with water and can cause critically low sodium levels. But the odds of you overhydrating with water … it takes a pretty decent amount.”

Faculty Participants

Jordan Clark, Ph.D.
Jordan Clark is a postdoctoral associate for the Heat Policy Innovation Hub and the Water Policy Program at the Nicholas Institute for Energy, Environment & Sustainability at Duke University, where he studies the effects of extreme heat.

J.J. Hoff, M.D.
Dr. J.J. Hoff is an emergency medicine specialist at Duke Health, assistant medical director for Duke Life Flight and medical director for Duke Event Medicine. He is an assistant professor in the Department of Emergency Medicine at Duke’s School of Medicine.

Ashley Ward, Ph.D.
Ashley Ward directs the Heat Policy Innovation Hub at Duke University’s Nicholas Institute for Energy, Environment & Sustainability. Ward’s work focuses on the health impacts of climate extremes and community resilience to the changing climate.