July's Deadly Surge: Is Heat the Culprit?

The Hidden Link Between Heat and Drug Overdoses in Los Angeles

Despite a significant drop in drug overdose deaths in Los Angeles over the past few years, there remains a troubling issue: July was the deadliest month for overdoses in the last decade, with 1,894 drug-related deaths recorded. This alarming trend has raised concerns among health experts about the role of extreme heat in exacerbating the risks associated with drug use.

According to Bharat Venkat, a UCLA professor and director of the university’s Heat Lab, “It’s very likely that a good chunk of those deaths are triggered by extreme heat exposure.” The connection between heat and drug-related fatalities is complex, involving multiple physiological and behavioral factors.

How Opioids Affect the Body in Extreme Heat

Opioids can significantly alter a person's internal temperature regulation. Dr. Pope Moseley, a lung and critical care physician who has studied the intersection of heat and drug toxicity, explains that “opioids alter your internal thermometer. You may not turn on the sweating as fast.” This impaired ability to regulate body temperature can lead to dangerous situations, especially when combined with high environmental temperatures.

Additionally, opioids can impair heat exchange through the skin and increase gut permeability. Under extreme conditions, this can result in heatstroke, respiratory failure, or sepsis. Dr. José Luis González, medical director of Healthcare in Action, notes that “if you’re falling asleep, then you’re not able to seek shelter once your body does get overheated.” The sedative effects of opioids can leave users vulnerable, unable to take necessary steps to cool down or seek help.

Methamphetamine and the Risks of Heat Exposure

Methamphetamine presents a different set of challenges. It can cause erratic behavior and increased physical activity, which can be particularly dangerous in hot environments. Users may not recognize the signs of overheating, leading to severe health complications.

In both cases, drug use can impair an individual's ability to respond to environmental heat, whether by actively cooling off or recognizing danger. Public cooling centers are designed to help vulnerable populations avoid the worst effects of heat, but they often exclude individuals who are visibly under the influence of drugs, thus missing the most at-risk group.

The Debate Over Heat-Related Deaths

While some experts argue that heat plays a significant role in drug-related deaths, officials in Los Angeles have cast doubt on this idea. A spokesperson from the Los Angeles County Department of Public Health stated that “the issue is more about folks being moved indoors during inclement weather and those people using drugs alone, versus in groups, which puts them at higher overdose risk.”

Official data from L.A. County show only 118 heat-related deaths from 2015 to 2024. However, previous analysis suggests that this number is likely an undercount. The health department spokesperson acknowledged that heat-related deaths may be underreported because heat can exacerbate chronic conditions like heart and respiratory disease but might not be recorded as a factor in death records.

Challenges in Death Certification

The process of certifying heat-related deaths is highly discretionary and varies across jurisdictions. Dr. Christina VandePol, former coroner of Chester County, Pa., noted that “there is no one guideline or criteria for certifying heat-related deaths, or in fact, any other kind of death.” While resources exist for medical examiners to consider environmental factors, these are mostly advisory rather than binding.

In contrast, some regions have implemented systematic approaches. For example, in Arizona, medical examiner offices in Pima and Maricopa counties require investigators to ask about heat in any deaths occurring between April and October. This approach led Maricopa County to report 645 heat-related deaths in 2023, compared to just 61 in 2014.

The Role of Medical Examiners in Los Angeles

In Los Angeles County, the approach to attributing heat as a cause or contributing factor to a death is highly discretionary. Dr. Odey C. Ukpo, the county’s chief medical examiner and coroner, explained that “each investigator takes note of the surroundings or circumstances around the death.” Heat-related deaths are often “a diagnosis of exclusion,” meaning that only after ruling out all other causes can heat be cited as the reason for a death.

Determining whether a death is “drug-related” involves examining the body, ruling out injury or natural disease as causes, and performing toxicology reports. Contrary to popular belief, “we don’t look at it and have a certain threshold” about how much a person used, Ukpo said. “It’s more deductive reasoning that nothing else can explain the death. Any level [of a toxin] can kill somebody.”

The Need for Better Data and Standardization

The lack of uniform standards across jurisdictions significantly impacts public health responses. VandePol emphasized that “anytime you’re not counting something, you can’t do anything about it.” If the problem isn’t recognized, it can’t be addressed effectively.

Los Angeles County has taken some steps to improve its processes, including integrating epidemiological analysis into death investigations. “We got an epidemiologist for the first time in our department’s history,” Ukpo said. “We are looking at cases, planning heat maps, surveillance and transient trends to better answer these questions.”

Conclusion

The disparities in how overdose deaths intersect with extreme heat highlight broader systemic issues, reflecting inconsistencies and gaps that may obscure the true effect of climate-related health risks in Los Angeles. As Dr. Moseley noted, “We need to start recognizing that heat is a killer.” Addressing this challenge requires better data, standardized protocols, and a commitment to understanding the complex interplay between heat, drug use, and public health.