Rick Rosner On, 35: Heat, Aggression, Long COVID, POTS, and Women’s Health
Author(s): Scott Douglas Jacobsen
Publication (Outlet/Website): Personal SubStack
Publication Date (yyyy/mm/dd): 2026/08/27
In this interview, Scott Douglas Jacobsen and Rick Rosner discuss heat, aggression, cognition, long COVID, autonomic dysfunction, and medical blind spots affecting women. They examine research linking higher temperatures with violent crime and reduced learning, consider POTS and post-COVID thermoregulatory problems, and discuss historical sex bias in biomedical research. Rosner also explains POTS and gastrointestinal disorders such as SIBO and intestinal methanogen overgrowth, while recalling David Letterman’s famously cold television studio as a production choice.
Heat, Violence, and Cognitive Effects
Scott Douglas Jacobsen: What’s traffic like on those 900-lane highways in Los Angeles? You can get road-rage violence, including shootings, and there really is evidence connecting higher temperatures with increased violence. A 2024 systematic review and meta-analysis found that higher temperatures were associated with increased violent crime, with a 10°C increase in short-term mean temperature associated with about a 9 percent increase in violent-crime risk across the studies that could be pooled.
But the mechanism isn’t simply that the frontal lobes “tax out.” Researchers have proposed several pathways, including physiological discomfort, irritability, sleep disruption, changes in social activity and exposure, and impaired cognitive or emotional regulation. We shouldn’t reduce it to one established neurological mechanism.
So there are decent physiological and social-psychological reasons to investigate the association between heat and aggression. The relationship between firearm availability and the lethality of violent encounters is a separate issue. And the heat-violence association isn’t unique to America.
Heat, Aging, and Physical Reactions
Rick Rosner: Carole and I have had unusually high temperatures for at least a month. We’ve each had physical reactions to the heat that we’ve never had before. I got canker sores, and Carole says she got headaches of a type she’s never had before.
She says all her friends have had bad reactions to the heat. The headaches could plausibly be related to heat or dehydration. I don’t know that you can attribute canker sores directly to heat. That’s much less established.
Part of it may also be that we’re all in our 60s now. As people age, thermoregulation can become less efficient, including changes in sweating and cardiovascular responses to heat.
COVID and Autonomic Regulation
Another thing is that most people have had COVID by now, and COVID can fuck up autonomic regulation in some people. Post-COVID autonomic dysfunction can include problems with heart rate, blood pressure, sweating, orthostatic tolerance, and, in some patients, thermoregulatory instability. But you can’t say that everybody who’s had COVID now has impaired temperature regulation.
So I would think there can be remnants of COVID where you don’t necessarily think of yourself as severely ill. However, persistent post-COVID symptoms that meet the relevant duration and clinical definitions are what we’d ordinarily call long COVID.
Jacobsen: You don’t need to have had severe acute COVID to develop long COVID.
Rosner: Yes. It’ll take decades to sort out everything.
You know, because you’ve interviewed a million people, how medicine and science have sometimes been shitty to women.
Women in Biomedical Research
Jacobsen: Historically, there have been several problems. Women were underrepresented or excluded from substantial areas of biomedical research, some conditions disproportionately affecting women received less attention, and women’s symptoms have sometimes been dismissed or interpreted differently from men’s.
Another problem was treating the male body as an implicit default in parts of biomedical research. That can create data gaps, and those data gaps can then become gaps in diagnosis and care.
On the heat issue, if violent crime increases during periods of high temperature, there could plausibly be related effects on interpersonal conflict. But I’d be careful about jumping directly from violent-crime statistics to divorce or breakup rates without evidence. Heat has been associated with increased interpersonal conflict and aggression, but each outcome needs to be studied separately.
Rosner: Yes. Or if people are sufficiently fucked up socially, there may be fewer relationships available to break up in the first place.
Jacobsen: Right.
POTS and Autonomic Dysfunction
Rosner: Do you know about POTS, which involves posture-related extreme changes in heart rate?
Jacobsen: No.
Rosner: POTS is postural orthostatic tachycardia syndrome. In adults, one core diagnostic feature is a sustained heart-rate increase of at least 30 beats per minute within 10 minutes of standing, without the blood-pressure fall that defines orthostatic hypotension, together with chronic orthostatic symptoms. It’s a form of autonomic dysfunction.
Extreme Heat and Student Learning
Jacobsen: One thing I wanted to point out: I found the study material on the main American Psychological Association site. They recently published a report saying rising temperatures are making it harder for students to learn and that many schools aren’t prepared for what that means.
The APA and its Network for Resilient PK-12 Schools in Extreme Climates reviewed evidence on how extreme heat affects students’ health, development, and ability to learn. They cite an optimal classroom range of roughly 68 to 73.4 degrees Fahrenheit, or 20 to 23 Celsius, and report that temperatures above that range can reduce speed and accuracy on cognitive tasks.
This is in schools, and those aren’t extreme temperatures. Once classrooms get hotter, measurable cognitive effects emerge. Other work has found lower academic performance on hot school days, while air conditioning mitigates some of the effect.
I propose that other aspects of human society probably show related effects, although adults aren’t simply immune because they have more developed prefrontal cortices. Adults also experience cognitive and physiological heat stress. The size and character of the effect can differ with age, health, acclimatization, hydration, cooling, and other factors.
Excessive heat may impair a broader range of human activities requiring attention, inhibition, decision-making, and emotion regulation. That’s a reasonable hypothesis, and parts of it are already supported, but we’d want evidence for each specific outcome.
David Letterman and the Cold Studio
Rosner: So David Letterman. Do you know about him and temperature? He kept the Ed Sullivan Theatre frickin’ cold, reportedly around 55 degrees Fahrenheit. That part is real. Letterman told Vanity Fair that he wanted it at 55 because if it were warmer, both he and the audience might become drowsy.
So that’s about 13 degrees Celsius, substantially colder than the classroom range you just mentioned. He believed a cold audience stayed alert and laughed better, and that warmth made people sluggish. The 55-degree temperature is well documented, although the claim that it actually improved laughter is Letterman’s production philosophy rather than a controlled scientific finding.
POTS, Women, and Diagnostic Delay
Anyway, POTS. Something like 80 to 85 percent of diagnosed POTS patients are women, particularly women of childbearing age.
It’s also a condition where patients have historically experienced significant diagnostic delay and misdiagnosis. Medicine didn’t recently discover POTS. The medical community has characterized the syndrome for decades. But awareness has been uneven, and studies show that patients, especially women, can have long diagnostic journeys and see multiple doctors before getting the diagnosis.
Your own doctor, particularly if they aren’t familiar with autonomic disorders, might not recognize it immediately, and you may end up seeing a specialist.
There’s a broader category of diseases and syndromes that are getting more attention now, including some that disproportionately affect women.
SIBO, IMO, and Gastrointestinal Symptoms
SIBO, small intestinal bacterial overgrowth, is another gastrointestinal condition, although I wouldn’t lump it into the same category as POTS or say it’s simply a women’s disease. It’s excessive microbial growth in the small intestine and can cause bloating, abdominal pain, nausea, diarrhea, constipation, and other gastrointestinal symptoms.
And the gas biology matters. Hydrogen-predominant SIBO is more often associated with diarrhea. Methane is strongly associated with constipation, but methane-positive cases are now more precisely called intestinal methanogen overgrowth, or IMO, because the methanogens aren’t bacteria and the overgrowth isn’t necessarily confined to the small intestine. Hydrogen sulphide has also been associated with diarrhea.
So, depending on the microbial ecology involved, you can get very different bowel symptoms, including constipation, diarrhea, bloating, and a lot of gas.
Jacobsen: Thank you very much for the opportunity and your time, Rick.
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