Episode #47 Can’t Take the Heat: The Health Consequences of Extreme Temperatures with Janelle Bludorn, PA-C

Dr. Albert Rizzo:
Welcome back to LungCast, the monthly respiratory health podcast series from the American Lung Association and the medical news site HCP Live. I’m your host, Dr. Albert Rizzo, Chief Medical Officer of the American Lung Association.

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Heat is an important environmental and occupational health hazard. Heat stress is the leading cause of weather-related deaths and can exacerbate underlying illnesses including cardiovascular disease, diabetes, asthma, and mental health conditions. It can also increase the risk of accidents and even transmission of some infectious diseases. Heat stroke in particular is a medical emergency with a high fatality rate.

We’re recording this in July 2024 during record-setting heat extremes across the country. More people are suffering serious burns from contact with hot outdoor surfaces like pavement and concrete. Some burns are so extensive they’ve been fatal. According to many burn experts, the number of people exposed to extreme heat is growing exponentially due to climate change. Between 2000 and 2019, studies show approximately 500,000 heat-related deaths occurred each year. For people over 65, heat-related mortality increased by about 85% between 2000–2004 and 2017–2021.

To give us perspective on this important topic, our guest today is Janelle Bludorn, Physician Assistant and Assistant Professor of Family Medicine and Community Health at Duke University. She has extensive experience in emergency medicine. Thank you for being here.

Janelle Bludorn:
Thank you so much, Dr. Rizzo. I’m very excited to join you on LungCast to talk about heat-related health impacts. I always like to begin by saying: no matter who you are or what you do, I hope you find value in this conversation.

For clinicians listening, I hope this elevates awareness of how to identify and manage heat-related illness, as well as how to provide strong patient education on prevention. For everyone else, I hope this helps you keep yourself and your loved ones safe in our hotter-than-ever world.

Dr. Rizzo:
Before we talk about respiratory consequences of extreme heat, could you give us an overview of heat-related illnesses you commonly see in emergency medicine?

Janelle Bludorn:
Absolutely. Extreme heat is now the number one weather-related cause of death in the U.S. In fact, it kills more people on average each year than hurricanes, floods, and tornadoes combined. Yet many people underestimate the risk of heat compared to dramatic events like wildfires or storms. This mismatch between actual danger and perceived risk leads to inadequate precautions, more ER visits, and higher mortality.

In the ER, we think of three main heat-related conditions:

1. Heat stroke – the most severe, with 20–60% mortality. Characterized by high body temperature, altered mental status, and eventually multi-organ failure.

2. Heat exhaustion – less severe, but still significant. Patients have high body temperature and dehydration, though mental status remains intact.

3. Heat cramps – painful muscle spasms after exertion in the heat, due to fluid and electrolyte losses.

Other conditions are emerging too, like kidney disease in agricultural workers and worsening of chronic respiratory disease during heat waves.

To understand why, it helps to know two concepts:

• Thermoregulation – the body’s ability to maintain core temperature between about 97–99°F. Controlled by the hypothalamus, it relies on vasodilation, sweating, and increased heart and breathing rates.

• Acclimatization – physiological adaptations that develop after repeated exposure to heat, making the body more efficient at handling it. This usually takes 1–2 weeks. Heat illness is more common when acclimatization doesn’t occur.

Dr. Rizzo:
That’s a great review. I’ve heard you speak before about assessing and screening individuals for heat risk. Can you explain that?

Janelle Bludorn:
Sure. In the ER, we usually assess risk after someone presents with illness. But there’s a huge opportunity for primary prevention—screening patients beforehand.

A 2022 New England Journal of Medicine article recommended that clinicians screen all patients before the hot season begins, to identify “heat-vulnerable” individuals. That involves looking at:

• Individual factors: age (young or elderly), chronic conditions (especially lung or kidney disease), pregnancy, medications, disabilities, social isolation, or immobility.

• Exposure risks: local climate, humidity, urban heat islands, occupation (outdoor workers, toll booth attendants, etc.), lack of home cooling, or indoor heat sources.

• Social and cultural factors: socioeconomic status, housing, structural racism, worker protections, literacy, and social support.

Once identified as vulnerable, patients and caregivers should be educated before the heat season. That means knowing symptoms (excessive sweating or suddenly stopping sweating), having a plan for cooling, hydration, power outages, and emergency contacts.

For high-risk groups like outdoor workers or athletes, prevention also includes frequent hydration breaks, breathable light clothing, hats/sunscreen, and avoiding midday heat.

Dr. Rizzo:
Let’s shift to the respiratory system. Weather, especially extreme heat, can worsen several respiratory diseases. A 10-year study in the American Journal of Respiratory and Critical Care Medicine showed hospitalizations for respiratory disease rise significantly with daily outdoor heat, independent of air pollution. Can you share your experience with this?

Janelle Bludorn:
The two biggest players are COPD and asthma. We see more exacerbations of both during heat waves.

Here’s why:

• The body works harder to regulate temperature, raising respiratory rate, oxygen demand, and metabolic demand.

• Hot air irritates airways, causing inflammation, coughing, and sometimes dehydration-related airway dryness.

• Heat often traps pollutants and particulates (like dust, soot, wildfire smoke, and pollen), which worsen asthma and COPD symptoms.

So, in practice, clinicians should anticipate more exacerbations during hot spells and be ready to identify, stabilize, and manage quickly using evidence-based care. Patients themselves should also be aware their threshold for flare-ups will be lower in heat.

Dr. Rizzo:
When preparing for this discussion, I came across something less familiar—how heat affects medications. Can you comment on that?

Janelle Bludorn:
Yes, and there are two main categories:

1. Medications that increase vulnerability to heat

   • Some impair sweating (antihistamines, tricyclic antidepressants, clonidine).

   • Some prevent vasodilation (beta-blockers, decongestants).

   • Others worsen dehydration or electrolyte imbalance (diuretics, laxatives, NSAIDs).

   • Some directly raise body temperature (stimulants, certain psychiatric medications, levothyroxine).

   • Even common meds like furosemide can increase sunburn risk.

2. Medications with logistical challenges in heat

   • Inhalers can burst above 120°F (like in a hot car).

   • EpiPens may malfunction.

   • Insulin loses potency if stored improperly.

   • Devices like nebulizers, CPAPs, or LVADs may fail during rolling blackouts, so patients need backup plans.

Dr. Rizzo:
The National Weather Service provides a heat risk indicator—color-coded and numeric. Have you found this helpful?

Janelle Bludorn:
Yes, because it’s simple and intuitive. Without reading details, people can glance at the map and understand risk—green is safe, magenta means extreme danger. It forecasts 7 days out and accounts for unusual heat, duration, and lack of overnight cooling, along with CDC health data.

Most people tolerate up to “orange” risk, but those with asthma—especially children—may need precautions at “yellow.” That means staying indoors or in cool spaces, ensuring medication storage, staying hydrated, and monitoring symptoms.

There’s also another measure, Wet Bulb Globe Temperature, used by the military and industries. It accounts for air temp, humidity, radiant heat, and wind. It’s less intuitive but increasingly important.

These indices are widely available in weather apps and on CDC/NWS websites, much like the AirNow.gov air quality index.

Dr. Rizzo:
Great review. To wrap up, what are your top recommendations for patients with lung disease during extreme heat?

Janelle Bludorn:
Here are key takeaways:

• Stay indoors with cooling or ventilation if possible.

• Check weather and air quality updates regularly.

• Plan outdoor activities for mornings or evenings, avoiding midday.

• Quit smoking; limit alcohol.

• Wear loose, light-colored clothing; cover exposed areas with hats or sunscreen.

• Avoid strenuous exercise in heat.

• Stay hydrated with water and high-water foods like fruits and vegetables.

• Use cooling strategies like showers or shade.

• Have an emergency plan, including quick-relief medications, properly stored.