About two-thirds of the record 425 deaths due to the heat last year involved some type of substance abuse, according to Maricopa County records. Methamphetamine was almost always the drug to blame.
Methamphetamine contributed to 90% of heat deaths involving drug use in 2022, and 53% of the county's heat deaths overall.
"Stimulants have multiple mechanisms to raise the body temperature," said Dr. Holly Geyer, an addiction medicine sub-specialist with Mayo Clinic. “They impair our ability to self-regulate; they prevent blood flow from going out to the periphery of the skin, and that prevents sweating; they even alleviate the unpleasant sense of overheating.”
Those effects can become lethal when combined with Arizona's summer temperatures. Geyer said in extreme heat like Phoenix has been having, it can take only a small amount of methamphetamine to send someone into an overdose.
She said if a person struggling with addiction is using the drug in this weather, it should be treated as a medical emergency.
"The most common symptoms someone could see is perhaps being unconscious, unable to be aroused, less responsive than usual after using a stimulant. All of those situations, we would recommend calling 911," Geyer said.
The number of heat-related deaths in Maricopa County has skyrocketed over the past decade, and the proportion of those deaths that involve drug use has also grown.
County data shows substance use was a factor in about 30% of the 110 heat deaths recorded in 2012. About 66% of last year's 425 heat deaths involved substance use.
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