Caleb Dresser, MD, MPH, attending physician in Emergency Department, recent graduate of Fellowship in Climate and Human Health at Beth Israel Deaconess Medical Center (BIDMC) 

Climate change and the extreme weather it brings, including heatwaves, hurricanes, and wildfires, impact not only land and infrastructure but human health as well. Through his work as an Emergency Medicine physician at BIDMC, Caleb Dresser, MD, MPH, continuously interacts with people from a variety of backgrounds and living situations in Massachusetts who are dealing with emergencies, and is uniquely qualified to observe how climate change in New England - in particular, heat, heavy rainfall, sea level rise and severe storms and hurricanes - can affect the health and well-being of his patients.  

During recent heatwaves, Dresser has personally cared for patients experiencing heat-related illnesses, and his training in climate change and related population health topics, including studies on the impact of housing and historical housing polices, has informed his awareness of what brings his patients to the BIDMC Emergency Department. “In my practice, we have to stay aware of the social and geographic dimensions of people’s lives,” Dresser says. “I now think of climate-related hazards, such as heat, as being similar to the social determinants of health.”  

Heat exhaustion and heat stroke are among the illnesses that Dresser sees in the Emergency Department.  In hot weather, the human body tries to cool off by sweating, breathing more quickly, and changing blood flow patterns to increase cooling. However, this physiology has limits; when exposed to high temperatures without adequate hydration for long enough, people can become dehydrated and stop being able to cool their bodies. As the systems that keep us at a normal body temperature start to fail and become unable to keep up with the demands of cooling the body, the internal temperature rises. Once body temperature exceeds about 104 Fahrenheit, the patient can develop symptoms such as rapid heartbeat, confusion or unconsciousness - characteristics of heat stroke. If the situation is not immediately corrected, multi-organ failure and death may occur. At very high temperatures the body’s proteins begin to de-nature (meaning they lose their structure, similar to what happens when we cook food), which causes permanent damage to a variety of organ systems.  

Heat stroke patients, Dresser says, come into the Emergency Department with a high body temperature and altered mental status. To manage these patients, Dresser and his team start continuous temperature monitoring and use aggressive external and internal cooling, which can include ice water baths, ice packs, cool mist and fans, cooled IV fluids, and in some cases invasive procedures to provide rapid internal cooling. Heat stroke is often a result of some circumstance in people’s lives they’re not in control of, such as a job, Dresser says. One high risk category is people who do heavy physical activity outside, for example outdoor laborers, athletes and military recruits. Social isolation also increases risk at the individual level, such as among elderly people who live alone, particularly in settings without air conditioning.  

Dresser sees prevention and early recognition of heat-related illnesses as crucial. Sitting in an air-conditioned room and drinking fluids are effective approaches to avoiding problems or treating mild heat exhaustion for someone who has a normal core body temperature, is awake and able to drink water. Unfortunately, this isn’t enough of an intervention for heatstroke patients, who are critically ill and need to get emergency medical care immediately. The management goal for patients with hyperthermia is rapid recognition of the disease, immediate cooling of the patient, and transport to the nearest emergency department.   

The first graduate  of the Fellowship in Climate and Human Health -- a new fellowship at BIDMC -- Dresser is now training future fellows and taking an active role to educate physicians and medical students, as well as the general public on the health implications of climate change, work that is further described in a recent publication in Health Affairs (1). Dresser also conducts research on the population health impacts of climate-related natural hazards - such as heat waves, wildfires, hurricanes, and other events that cause population displacements - that may be actionable from the perspective of non-profits, government agencies and healthcare institutions. 

His recent work has included a review of heatstroke treatment guidelines (2), reviews and commentaries on climate-related population movements (3,4), and a synopsis of the relationship between climate change and the risk of Vibrio infections for the 2020 Lancet Countdown on Health and Climate Change Policy Brief for the United States of America (5). He has also delivered a wide range of lectures and panels on climate change, health, and heatwaves for both professional and public audiences. 


  1. Lemery J, Balbus J, Sorensen C, Rublee C, Dresser C, Balsari S, Calvello Hynes E. Training ClinicalAnd Public Health Leaders In Climate And Health. Health Aff (Millwood). 2020 12; 39(12):2189-2196. PMID: 33284695. 
  2. 2.Rublee, Caitlin; Dresser, Caleb; Giudice, Catharina; Lemery, Jay; Sorensen, Cecilia. Evidence-Based Heatstroke Management in the Emergency Western Journal of Emergency Medicine. 2021. 
  3. Balsari S, Dresser C, Leaning J. Climate Change, Migration, and Civil Strife.Curr Environ Health Rep. 2020 12; 7(4):404-414. PMID: 33048318. 
  4. Anish Parekh, MD, MPH; Caleb Dresser, MD; Sarah Kimball, MD. Society of General Internal Medicine Forum. Health Impacts of Climate Mobility in the United States. 2021; 44(3):8
  5. 5.Dresser C, Rublee C. Climate Change and Vibrio. The Lancet Countdown on Health and Climate Change Policy Brief for the United States of America: Appendix. 2020; 13.

Links to full text for these articles are here: 

Links to video of some of the talks / panels is here: