Latest / Wellness, Actually with Emily Oster & Perry Wilson, MD / What's the deal with cortisol?
Transcript
- 0:00Speaker 1: Emily. We're talking about cortisol today, which people say is
- 0:04Speaker 1: a stress hormone, and yeah, we'll get there. But I've
- 0:07Speaker 1: been thinking a lot about stress this week, and one
- 0:10Speaker 1: thing I wanted to tell you is that my fitness
- 0:13Speaker 1: tracking watch, which is a Samsung watch, periodically pings me
- 0:17Speaker 1: just to be like, hey, you're feeling very stressed right now,
- 0:21Speaker 1: and this.
- 0:22Speaker 2: Is that sounds so annoying.
- 0:24Speaker 1: Not helpful, Samsung. I have no idea why. Like, it'll
- 0:30Speaker 1: come up and I as a doctor, you know, I'll
- 0:33Speaker 1: take my pulse and be like, it's something weird happening,
- 0:36Speaker 1: and I think I feel fine, But then of course
- 0:38Speaker 1: it gets in your head it's like, what, well am
- 0:41Speaker 1: I stressed? And then I decide, well, I must be stressed,
- 0:43Speaker 1: and then I'm stressed. Does this happened to you?
- 0:46Speaker 3: No, because my fitness tracker, of which I have two,
- 0:49Speaker 3: give me different kinds of inputs. But I will say
- 0:51Speaker 3: at the end of the day, every day I get
- 0:53Speaker 3: a message that's like, today you spent blah blah blah
- 0:57Speaker 3: minutes in the high stress zone. And then it tells
- 1:01Speaker 3: me whether those are like part of my actual exercise
- 1:06Speaker 3: or other things sort of like today you spent two
- 1:08Speaker 3: hours and nine minutes in the high stress zone, the
- 1:10Speaker 3: majority of which came from activities outside of strain. And
- 1:14Speaker 3: then it's like, oh, well, what else was I what
- 1:16Speaker 3: else was I doing? And then it's usually like usually
- 1:18Speaker 3: this came from sleep, and then I'll be like.
- 1:20Speaker 2: Why did you drink alcohol?
- 1:21Speaker 3: That's like it's like, so it gets a little more judgmental,
- 1:24Speaker 3: but yeah, people don't like the judgment aspects of watches.
- 1:28Speaker 3: It's like, I, do you ever do you run with
- 1:30Speaker 3: a watch?
- 1:30Speaker 2: I do exercise. Do you notice that when you start.
- 1:34Speaker 3: Running it beeps a number like plus one, plus two,
- 1:38Speaker 3: negative one?
- 1:39Speaker 2: Does your watch do this?
- 1:40Speaker 1: My watch doesn't do that.
- 1:41Speaker 2: This is the worst thing.
- 1:42Speaker 3: You're like running along and you're like I feel pretty
- 1:44Speaker 3: good and then your watch beeps and it's like negative
- 1:46Speaker 3: six and that you suck it, your bad And so
- 1:51Speaker 3: I think they should dial down the amount of information
- 1:53Speaker 3: our watches are pushing at us.
- 1:54Speaker 1: I think telling someone, hey, you your stressed man is
- 1:59Speaker 1: more or less the equivalent of me telling my sixteen
- 2:01Speaker 1: year old daughter, like, you seem like you're in a
- 2:04Speaker 1: bad mood, Like it's just just it's not going to
- 2:07Speaker 1: go well.
- 2:08Speaker 3: One step up from like are you getting your period?
- 2:11Speaker 3: But like it still pretty bad?
- 2:13Speaker 1: Okay, having three older sisters, I know not to ask
- 2:16Speaker 1: that question. You'll learn that. You learn that maybe we
- 2:19Speaker 1: need a more objective readout of stress. Maybe that objective
- 2:22Speaker 1: readout is cortisol. Maybe not. Let's figure it out, find out.
- 2:29Speaker 3: I'm Emily Aster, I'm an economist and a data expert.
- 2:32Speaker 1: And I'm Perry Wilson, I'm a medical doctor.
- 2:34Speaker 3: It's Thursday, July ninth, twenty twenty six. And this is wellness.
- 2:38Speaker 1: Actually, because you're getting a staggering amount of health and
- 2:42Speaker 1: wellness information nowadays from every source imaginable, and some of
- 2:46Speaker 1: it is awesome and some.
- 2:48Speaker 3: Of it is well actually both Fortunately we are both
- 2:53Speaker 3: people who know how to read studies, how to parse
- 2:56Speaker 3: the data, and can tell you what's worth thinking about
- 2:59Speaker 3: and what you can safely ignore.
- 3:01Speaker 1: But before we dig in, a note that this podcast
- 3:03Speaker 1: is for educational purposes and should not be construed as
- 3:06Speaker 1: medical advice. We don't know your unique situation, so talk
- 3:09Speaker 1: to your doctor for personal health decisions.
- 3:12Speaker 2: This week we're asking what's the deal with cortisol?
- 3:15Speaker 3: Perry and I will give the official smasher pass and
- 3:18Speaker 3: then we'll get to your question of the week, but
- 3:20Speaker 3: first let's do the health news roundup after the break.
- 3:34Speaker 1: And we are back with the health news of the week, Emily.
- 3:38Speaker 1: The FDA is allowing Zin pouches to market their relative
- 3:45Speaker 1: health benefits compared to other tobacco products like cigarettes. What's
- 3:51Speaker 1: going on here? What's up with zin?
- 3:54Speaker 2: So Zin is a tobacco product.
- 3:57Speaker 3: It is a nicotine product particular, and people like it
- 4:02Speaker 3: a lot of people like it a lot. It's become
- 4:05Speaker 3: very popular with like tech bros. Because there's this sense
- 4:09Speaker 3: that nicotine increases your focus, and people like Andrew Huberman
- 4:13Speaker 3: are kind of into the health benefits of nicotine, but
- 4:16Speaker 3: they also understand this smoking is bad for you, and
- 4:18Speaker 3: so this is like a way to get your nicotine
- 4:21Speaker 3: without smoking. And Okay, so the FDA has now allowed
- 4:27Speaker 3: Zin to make help what I would describe as health statements.
- 4:31Speaker 3: So the claim things like using Zin instead of cigarettes
- 4:34Speaker 3: puts you at a lower risk of mouth cancer, heart disease,
- 4:36Speaker 3: lung cancer, stroke emphasem, and chronic broncholitis that statement is.
- 4:41Speaker 2: I would say broadly true.
- 4:43Speaker 3: So these products are definitely safer than cigarettes. I think
- 4:46Speaker 3: what many people are concerned about is that children will
- 4:50Speaker 3: see this and be like, hey, Zen's a health food
- 4:55Speaker 3: and like I can do and this is like not
- 4:56Speaker 3: bad for me at all. And on top of an
- 4:59Speaker 3: app atmosphere in which you can also get as we
- 5:02Speaker 3: talked about an earlier episode, like fruit flavored vapes, we're
- 5:05Speaker 3: kind of entering a place where somehow we've come up
- 5:09Speaker 3: with this idea that there's health benefit opportunities to things
- 5:13Speaker 3: that are not cigarettes but still have this nicotine. And
- 5:15Speaker 3: I think that's pretty dangerous in part because if you
- 5:19Speaker 3: get addicted to nicotine and then there's no zin around,
- 5:23Speaker 3: you got to move to something else, like cigarettes, which
- 5:27Speaker 3: are bad for you.
- 5:28Speaker 1: Yeah, or just zin, I mean this is or just zin.
- 5:32Speaker 2: Is bad for you. We don't really.
- 5:33Speaker 1: I mean this is true that smoking, like lighting something
- 5:37Speaker 1: on fire and inhaling the smoke that comes out of it,
- 5:39Speaker 1: is worse for your lungs than sucking on a nicotine pouch.
- 5:43Speaker 1: This is, Yes, you're at less risk of lung cancer,
- 5:46Speaker 1: but nicotine is a highly addictive substance. It binds to
- 5:49Speaker 1: a receptor in your brain called the NMDA receptor. It
- 5:52Speaker 1: makes you feel certain good things and like all physically
- 5:55Speaker 1: addictive substances. When it's taken away from you, you feel
- 5:59Speaker 1: much worse you did at baseline. The psychological impact of
- 6:04Speaker 1: that may be substantial. Certainly the economic impact is substantial
- 6:08Speaker 1: because these things cost money. And being addicted to something
- 6:10Speaker 1: that you need to take, even if it had like
- 6:12Speaker 1: absolutely no ill health effects, if it's just like, oh man,
- 6:15Speaker 1: I've got to buy this every day and keep sucking
- 6:18Speaker 1: on it, imposes a cost. So it's an interesting shift
- 6:22Speaker 1: at the FDA where they're kind of being accurate, but
- 6:24Speaker 1: I think from a public health standpoint, they're not doing
- 6:26Speaker 1: a great job telegraphing that, like this still isn't a
- 6:28Speaker 1: good idea.
- 6:29Speaker 3: Yeah, I also think we're we're actually in terms of
- 6:32Speaker 3: the health benefits or costs of nicotine. You know, there's
- 6:36Speaker 3: some research that nicotine kind of increases focus, but I
- 6:39Speaker 3: don't know that we have anything that would tell us
- 6:43Speaker 3: about the health potential health costs of consuming quite a
- 6:46Speaker 3: lot of nicotine, which is effectively what people are doing
- 6:49Speaker 3: when they're consuming many many zinn pouches in a day.
- 6:51Speaker 3: So we're getting kind of a dose that's even a
- 6:53Speaker 3: bit different probably than we've been tested and say mice. Yeah, Anyway,
- 6:58Speaker 3: all right, something else that's going on is an outbreak
- 7:01Speaker 3: of explosive diarrhea. Cyclospora outbreak is happening throughout the US,
- 7:07Speaker 3: especially in places in the Midwest.
- 7:11Speaker 2: Perry, what can you tell.
- 7:12Speaker 3: Us about the explosive diarrhea and where it's coming next
- 7:16Speaker 3: and why?
- 7:17Speaker 1: Uh okay. Cyclospora is a parasitic amiba that causes a
- 7:24Speaker 1: really bad gastro intestinal illness voluminous, watery, non bloody. For
- 7:30Speaker 1: what it's worth, diarrhea people are going dozens of times
- 7:35Speaker 1: per day, can lead to pretty severe dehydration, including the
- 7:38Speaker 1: need for ivy fluids, et cetera. Current numbers, there are
- 7:42Speaker 1: seven hundred reported cases. This is a one of the
- 7:48Speaker 1: reportable outbreak, So like if you get a positive test,
- 7:50Speaker 1: and if you run a clinical lab and a positive
- 7:52Speaker 1: test comes through, you're required to report it, so we
- 7:55Speaker 1: catch those, But there are likely people who are suffering
- 7:58Speaker 1: in silence at home and their gatorade and not getting
- 8:01Speaker 1: officially tested for this. It's predominantly in the Midwest. The
- 8:07Speaker 1: concern is that we actually don't know the source. So
- 8:10Speaker 1: it's clear that you know where a cyclist bora usually
- 8:15Speaker 1: lives is on produce and particularly like mint and parsley,
- 8:21Speaker 1: like the sort of garnishy produce, as well as berries,
- 8:23Speaker 1: which gets into my head because the berries are so
- 8:26Speaker 1: good right now, and I like am getting blueberries and
- 8:28Speaker 1: strawberries and raspberries and blackberries all the time at my
- 8:31Speaker 1: grocery store. But so far testing has not revealed a
- 8:35Speaker 1: particular source. It is certainly out there.
- 8:38Speaker 3: It's I should say, it's actually a hard thing to
- 8:41Speaker 3: test exact sources for because it takes The incubation period
- 8:44Speaker 3: is not immediate. So if there's something which makes you
- 8:47Speaker 3: sick in you know, three hours, it's actually quite easy
- 8:50Speaker 3: to say, Okay, you know a group of people got
- 8:53Speaker 3: sick within three hours, we know exactly what they ate
- 8:55Speaker 3: three hours ago. Okay it was spinach or whatever. Here
- 8:58Speaker 3: it takes a while. People don't remember what they eight.
- 9:00Speaker 3: They ate a lot of different things. It's been hard
- 9:02Speaker 3: to pinpoint.
- 9:03Speaker 2: Yeah.
- 9:03Speaker 1: One thing I was looking into about this because my
- 9:05Speaker 1: daughter gave me a hard time the other day because
- 9:07Speaker 1: I made her a hamburger and she said it was
- 9:09Speaker 1: undercooked and she's very afraid of gastrointestinal illnesses. And you sure,
- 9:14Speaker 1: but you know, yes, I guess you should cook your
- 9:16Speaker 1: meat adequately, but like, come on, a rare hamburger is
- 9:19Speaker 1: just the best thing in July. So I did dig
- 9:22Speaker 1: into this to see, like gastro intestinal illnesses in the
- 9:26Speaker 1: United States, what percent come from meat and poultry versus produce?
- 9:31Speaker 1: And actually forty six percent of the food born illnesses
- 9:34Speaker 1: come from produce and thirty one percent from meat and poultry,
- 9:37Speaker 1: which leaves I don't know whatever percent. I'm not sure
- 9:39Speaker 1: what else, but more often, more often from produce. Yeah,
- 9:43Speaker 1: could be things like that, but produce is the most
- 9:45Speaker 1: common source for food born illnesses in the US. You
- 9:49Speaker 1: should wash your produce, and guys, it's watermelon season, like
- 9:54Speaker 1: you should be washing the outside of your watermelon. I
- 9:56Speaker 1: know you think that you're cutting into it, but you
- 9:58Speaker 1: know you cut through the skin and it goes through.
- 10:02Speaker 1: That's my own that you can suffer.
- 10:05Speaker 2: Your safety perries here for ruining everything.
- 10:08Speaker 1: Washa, I'm not ruining it. Just wash it and then
- 10:11Speaker 1: it's delicious. All right. Let's talk about a new secret
- 10:18Speaker 1: shopper study of these GLP one websites. So, as you know,
- 10:23Speaker 1: there are multiple websites online that market GLP ones, and
- 10:28Speaker 1: a new study actually out of Yale. Although I wasn't
- 10:30Speaker 1: affiliated with it, set up a fake persona and called
- 10:34Speaker 1: forty nine of these websites and was able to get
- 10:37Speaker 1: a prescription from forty five of the forty nine, and
- 10:40Speaker 1: two of them issued a prescription in under five minutes. Emily,
- 10:45Speaker 1: problem or solution, I.
- 10:50Speaker 3: Would say problem. I mean, look, we've talked about this before.
- 10:54Speaker 3: I'm a smashed broadly on GLP ones as a treatment
- 10:58Speaker 3: for many things, and I think this is an incredible technology. However,
- 11:02Speaker 3: it is a medication, injectable, medication or now oral, but
- 11:05Speaker 3: like it's a medication that has significant effects on people
- 11:10Speaker 3: and should ideally be prescribed by a doctor who has
- 11:14Speaker 3: had some interaction with the patient. And I do worry
- 11:19Speaker 3: about people who are really don't need this or for
- 11:22Speaker 3: whom maybe it's even kind of damaging in the sense that,
- 11:26Speaker 3: you know, we have seen some concerning at least anecdotal
- 11:30Speaker 3: evidence about me people have suffered from meeting disorders in
- 11:33Speaker 3: the past, this kind of this environment reupping those and
- 11:36Speaker 3: I would worry about people in that category calling an
- 11:38Speaker 3: online pharmacy and saying, hey, I feel like I need
- 11:40Speaker 3: a JLP one similar to an article I saw come
- 11:44Speaker 3: across my Instagram feeds. Just a clip of someone saying
- 11:48Speaker 3: that the way that she got a JLP one was
- 11:50Speaker 3: by wearing twenty pound ankle weights to the doctor so
- 11:55Speaker 3: she could weigh the like required one hundred and sixtys
- 12:00Speaker 3: to get on a GLP one, even though she was
- 12:03Speaker 3: only one hundred and twenty pounds, which probably does not
- 12:06Speaker 3: necesssitate needing a JLP one.
- 12:08Speaker 2: So that feels bad to.
- 12:10Speaker 1: Me, Yeah, that should feel bad. Just over fifty percent
- 12:13Speaker 1: of the sites asked about eating disorders at all in
- 12:16Speaker 1: their intake surveys, so there is some potential missed opportunities there.
- 12:21Speaker 1: And I should say that almost all the sites are
- 12:23Speaker 1: selling compounded GLP ones. They do this by making custom preparations.
- 12:28Speaker 1: They take bulk amounts of like ozembic or munjaro, dissolve
- 12:32Speaker 1: them in their own water, and then you have to
- 12:34Speaker 1: add something to personalize it to the patients. They usually
- 12:36Speaker 1: add like some B twelve or something so that it's
- 12:39Speaker 1: not exactly the same as the branded pharmaceutical. So it's
- 12:41Speaker 1: in this very regulatory gray zone. You got to be careful.
- 12:44Speaker 1: I mean, you know. Again, there's a flip side of this,
- 12:48Speaker 1: and I actually wrote about this this week, which is like,
- 12:50Speaker 1: if it's this easy, then should there be prescriptions at all?
- 12:55Speaker 1: Like this middle road of oh yeah, there are prescriptions,
- 12:58Speaker 1: but everyone can fake it seem sort of dumb. So
- 13:01Speaker 1: you either close these loopholes and you actually have to
- 13:03Speaker 1: see a doctor and discuss it, or you don't and
- 13:06Speaker 1: you just let people buy the things and the libertarians win.
- 13:09Speaker 2: Right, Yeah, and I think we have either.
- 13:11Speaker 3: Yeah, we haven't made that choice with most other medications.
- 13:14Speaker 3: And I think most people would not make the argument
- 13:15Speaker 3: that we should be allowing people to you know, take
- 13:18Speaker 3: statins whenever or you know, just get on different But
- 13:22Speaker 3: maybe maybe people would argue that.
- 13:26Speaker 1: All right, that's in for the health news of the
- 13:27Speaker 1: week after the break. What's the deal with cortisol?
- 13:36Speaker 3: All right, Perry, I am delighted to talk about cortisol,
- 13:40Speaker 3: something I've heard a lot about.
- 13:42Speaker 2: As a woman in her let's say, mid to late forties.
- 13:47Speaker 3: I'm aware that raising my cortisol too high will lead
- 13:50Speaker 3: to the dreaded belly fat. And I'm sure we'll get
- 13:54Speaker 3: later to the many ways in which my bones are
- 13:56Speaker 3: attorney to dust due to my high cortisol. Belly fat combo.
- 14:00Speaker 3: Oh it's terrible. But before we get into this just
- 14:04Speaker 3: for people who are getting all their information about cortisol
- 14:07Speaker 3: from the same Instagram that I'm getting it from. Let's
- 14:10Speaker 3: start by defining what is cortisol and what are we
- 14:16Speaker 3: actually talking about here overall.
- 14:19Speaker 2: So you're a doctor, tell.
- 14:20Speaker 1: Me, yeah, oh man, cortisol gets such a bad rap
- 14:25Speaker 1: online and it's such a critical hormone, it's so important.
- 14:28Speaker 1: So cortisol is a steroid hormone. We've talked about these
- 14:30Speaker 1: several times before and wellness. Actually, steroid hormones are really
- 14:35Speaker 1: interesting because the site that they act on is in
- 14:38Speaker 1: the nucleus, is with the DNA of a cell. So
- 14:41Speaker 1: all the steroid hormones, including things like testosterone and estrogen,
- 14:45Speaker 1: get into the nucleus and change how DNA is transcribed,
- 14:49Speaker 1: so it can fundamentally change what cells are doing, which
- 14:52Speaker 1: means all these things can do a million different things.
- 14:56Speaker 1: It's not like you know this one protein is responsible
- 14:59Speaker 1: for or you know, increasing your sugar level or decreasing
- 15:02Speaker 1: your sugar level. It does a million things. And I
- 15:04Speaker 1: think the best way to sort of think about cortisol
- 15:08Speaker 1: is that it is there primarily to save your life
- 15:13Speaker 1: in the next ten minutes at the expense of the
- 15:16Speaker 1: next ten years. So cortisol is a hormone that's present
- 15:22Speaker 1: to keep you moving and alive after something really bad
- 15:26Speaker 1: has happened to you, like you got mauled by a
- 15:28Speaker 1: saber toothed tiger, or you are, you know, running from
- 15:32Speaker 1: something that is trying to eat.
- 15:34Speaker 3: You can I'm gonna pause you there because I think
- 15:38Speaker 3: for most people the thing they think is driving that
- 15:41Speaker 3: is adrenaline.
- 15:42Speaker 2: So when you tell me you were chasing by a tiger,
- 15:44Speaker 2: I think adrenaline. Yeah, they're not the same.
- 15:48Speaker 1: They're not the same. And cortisol is secreted by the
- 15:51Speaker 1: adrenal glands, which is where adrenaline comes from. Two and
- 15:55Speaker 1: they are by all means related and evolutionarily followed kind
- 15:59Speaker 1: of similar. But adrenaline is much more cardiovascularly active in
- 16:04Speaker 1: terms of like flogging your heart and whatnot, whereas cortisol
- 16:10Speaker 1: is more focused on sugar levels. So when you're being
- 16:14Speaker 1: chased by a tiger, you want there to be plenty
- 16:16Speaker 1: of sugar in your blood for your muscles to use
- 16:19Speaker 1: and for your brain to use. And you really don't
- 16:21Speaker 1: care about whether there's energy for your gut or your
- 16:26Speaker 1: liver or like your bones, or for your immune system even,
- 16:31Speaker 1: which is a very energetic, energy intensive thing. So you're
- 16:34Speaker 1: kind of like shutting everything down and focusing all that
- 16:38Speaker 1: glucose into muscle and brain. And so when you give
- 16:42Speaker 1: someone cortisol or when they're indogenous, when their own cortisol
- 16:45Speaker 1: goes up, their blood sugar goes up, their immune system
- 16:49Speaker 1: ramps down. That's why glucocorticoids, which are cortisol derivatives, are immunosuppressants,
- 16:57Speaker 1: things like prednozone. Many people have used hydro cortizone cream
- 17:01Speaker 1: like for itches and stuff like that. So hydro cortizone
- 17:05Speaker 1: is cortisol, the exact same molecule. There's no difference between
- 17:08Speaker 1: hydro cortizone and the cortisol that you're adrenal land secretes.
- 17:12Speaker 1: I mean they put it in a cream obviously, But
- 17:15Speaker 1: that's what it is. The problem that people attribute to cortisol,
- 17:20Speaker 1: and sometimes incorrectly, as we'll go into, is like, what
- 17:23Speaker 1: if that stressor lasts longer than twenty minutes, Right, you're
- 17:28Speaker 1: running away from the tiger. Oh, you made it away
- 17:29Speaker 1: from the tiger. Great, you're good, everything's safe, everything can
- 17:31Speaker 1: go back to normal. What if your whole what if
- 17:34Speaker 1: your whole life is stressor what if you're constantly feeling
- 17:37Speaker 1: like you're being chased by a tiger and your cortisol
- 17:40Speaker 1: levels are high all the time, and it tells a
- 17:44Speaker 1: really nice story that like, ooh, that would do a
- 17:46Speaker 1: lot of bad things. But as I said, cortisol gets
- 17:50Speaker 1: a bad rap, and it might not be as bad
- 17:53Speaker 1: as you think.
- 17:55Speaker 3: So in terms of just sort of people thinking about
- 17:57Speaker 3: like the way that their quarter so moves throughout the day,
- 18:02Speaker 3: because cortisol is a it is a hormone, and it
- 18:05Speaker 3: would be a mistake to think of it as just
- 18:07Speaker 3: always flat except when you're chased by a tiger. It
- 18:10Speaker 3: is something which is fluctuating through the day. It's highest
- 18:14Speaker 3: in the morning, so when you sort of first wake
- 18:16Speaker 3: up in the morning, your cortisol tends to be tends
- 18:19Speaker 3: to be higher, and it's lowest sort of in the
- 18:22Speaker 3: middle of when you are asleep, is my sense, like
- 18:24Speaker 3: on average for most people, and then it will spike
- 18:28Speaker 3: at times during the day. This is something that's quite
- 18:31Speaker 3: hard to measure, but in principle it would spike when
- 18:33Speaker 3: you are doing either physically or emotionally stressful activities like
- 18:37Speaker 3: running from a tiger is that true.
- 18:39Speaker 1: Yeah, yeah, yeah. The morning cortisol spike is well described.
- 18:44Speaker 1: It is one of the reasons why heart attacks are
- 18:47Speaker 1: more common in the early hours of the morning, for example,
- 18:50Speaker 1: because your body's sort of revving up to get ready
- 18:53Speaker 1: to wake up the day. And we will get to
- 18:57Speaker 1: this is a circadian rhythm, like one of our fundamental
- 19:01Speaker 1: circadian rhythms. It's about five times higher in the morning
- 19:04Speaker 1: than it is at night. I mean, it's a real
- 19:06Speaker 1: it's a real shift over time. And if you really
- 19:09Speaker 1: dig into the data, you'll find that the level of
- 19:14Speaker 1: cortisol might not be as important as the circadian rhythm
- 19:18Speaker 1: of cortisol. So one of the things we see in
- 19:20Speaker 1: the truly chronically stressed are actually not high cortisol levels.
- 19:24Speaker 1: It's a loss of that fluctuation. It's flat cortisol levels. Yeah.
- 19:28Speaker 3: So I think that's a good that's a good pivot
- 19:30Speaker 3: into what I the first piece of what's tough about
- 19:34Speaker 3: this entire discussion is going to be really hard about
- 19:37Speaker 3: the data, which is like what are we measuring and
- 19:39Speaker 3: when are we measuring?
- 19:40Speaker 2: So this is not there are some things we measure in.
- 19:43Speaker 3: People where I think we can say, you know, maybe
- 19:45Speaker 3: you want to do some repeat measurements, but like we
- 19:47Speaker 3: have a good sense like something like you know like
- 19:49Speaker 3: a one C levels for like a diabetic. You know
- 19:52Speaker 3: you test me we you test it fasting not fasting.
- 19:54Speaker 3: But we have a good sense, we have a stable
- 19:57Speaker 3: sense of like how we test that, and we could
- 19:59Speaker 3: use to say, you know you're a diabetic, you're not
- 20:01Speaker 3: a diabetic. Measurements of cortisol which are done typically through
- 20:06Speaker 3: your blood, although actually they can also do saliva, you
- 20:09Speaker 3: can also do hair. You have many different ways to
- 20:12Speaker 3: test this. They don't all test the same thing.
- 20:14Speaker 2: And because there's this fluctuation, it's actually a really really
- 20:18Speaker 2: hard thing to hit.
- 20:20Speaker 3: If you wanted to say, what's the number that's going
- 20:22Speaker 3: to tell me I'm chronically stressed in some dangerous way,
- 20:25Speaker 3: there's sort of no number like that.
- 20:27Speaker 1: Yeah, and actually it's a lab test that's pretty bad.
- 20:30Speaker 1: So there's some lab tests like sodium level that's just
- 20:34Speaker 1: it's been figured out and we can do it really
- 20:36Speaker 1: quickly and it's highly accurate, and you test the same
- 20:38Speaker 1: blood sample twice and you get the same number, and
- 20:40Speaker 1: like it's really nice, and cortisol just isn't one of
- 20:42Speaker 1: those things. I mean One of the major issues is
- 20:44Speaker 1: that ninety five percent of cortisol in your blood is
- 20:47Speaker 1: bound to proteins and is inactive, so these are just
- 20:53Speaker 1: chaperone proteins that carry it around. And then the free fraction,
- 20:56Speaker 1: the five percent, is the thing that does stuff in
- 20:58Speaker 1: your cells. But almost all the lab tests out there
- 21:01Speaker 1: are measuring the total, so you know that's is it
- 21:05Speaker 1: correlated with the free Yeah, but not great and it's
- 21:09Speaker 1: hard to know. There's obviously the timing of measurement that's
- 21:13Speaker 1: really important, so you know, you really want to get
- 21:15Speaker 1: if you actually needed to measure cortisol, for example, to
- 21:18Speaker 1: tell if you have a disease of excessive cortisol production.
- 21:21Speaker 1: And these diseases exists called Cushing syndrome or Cushing's disease,
- 21:26Speaker 1: you get a test early in the morning when you've
- 21:28Speaker 1: got the best chance of capturing things high. The assays
- 21:32Speaker 1: that they use for cortisol have a lot of false positives,
- 21:35Speaker 1: so there's cross reactivity with a bunch of other hormones
- 21:39Speaker 1: and other substances that people are taking in It's just
- 21:42Speaker 1: like I mean, I'll say right now, like getting your
- 21:44Speaker 1: cortisol measured if you don't have symptoms of a cortisol
- 21:48Speaker 1: excess disease is you're unlikely to get any useful information.
- 21:54Speaker 3: So I think, okay, So when we talk about the
- 21:57Speaker 3: way to measure cortisol, actually measuring blood has both the
- 22:00Speaker 3: total and free fraction issue. It also has the issue
- 22:03Speaker 3: that when you take someone's blood, it raises their cortisol.
- 22:07Speaker 1: Yeah, because stressful.
- 22:08Speaker 3: It's like, it's stressful, like somebody's sticking a needle in
- 22:10Speaker 3: your arm and you're like, and it's a tiger, Like
- 22:12Speaker 3: I better get ready to run away.
- 22:14Speaker 2: It's not a tiger. You ask for that.
- 22:16Speaker 3: But as a result, like saliva is in some sense
- 22:19Speaker 3: the sort of best metric of this at a moment,
- 22:23Speaker 3: because it's not stressful to take someone's saliva. But the
- 22:26Speaker 3: thing that I wonder is why, you know we have
- 22:29Speaker 3: continuous glucose monitors. Why has someone not made something that
- 22:33Speaker 3: I stick in my You could put it on his
- 22:35Speaker 3: zin pouch, something I stick in my mouth and leave
- 22:38Speaker 3: in my mouth all the time, on like the side
- 22:40Speaker 3: of my cheek, and then it constantly measures my quarter cel.
- 22:43Speaker 3: Don't you think Brian Johnson would buy that in like
- 22:45Speaker 3: one hot second, Like why is the market not delivering
- 22:48Speaker 3: that Perry.
- 22:48Speaker 1: What's the problem, No doubt people are pitching that in
- 22:52Speaker 1: Silicon Valley right now.
- 22:54Speaker 3: Call me, call me VC funds. We're gonna measure the
- 22:58Speaker 3: cortisol with our mouths stick stick.
- 23:02Speaker 1: I think two things. One, cortisol is complicated to measure.
- 23:05Speaker 1: It's you know, it's a it's a hormone. It's it's
- 23:09Speaker 1: it's a bigger molecule than something like glucose, which is
- 23:12Speaker 1: small and easy to measure. And then the second thing
- 23:14Speaker 1: is that nobody knows what to do with the answer.
- 23:17Speaker 1: I could tell you what your cortisol is.
- 23:18Speaker 3: That's not the answer. I'm sorry, that's not the answer
- 23:20Speaker 3: to why they're constantly met. People love to measure stuff
- 23:22Speaker 3: or something to do it. The first answer was right, Scott,
- 23:24Speaker 3: you should have stopped at that one.
- 23:26Speaker 1: Okay, we will erase the second. Now it's fine. I
- 23:28Speaker 1: can be wrong sometimes.
- 23:30Speaker 3: Okay, So this is very hard to measure, and we'll
- 23:33Speaker 3: get into like why that probably means you shouldn't you
- 23:36Speaker 3: shouldn't measure it. But despite its difficulty in measuring, there
- 23:40Speaker 3: is actually a fair amount of research on the relationship
- 23:44Speaker 3: between cortisol measured in some way. We will get to
- 23:47Speaker 3: and various health outcomes, and I will just like spoiler,
- 23:52Speaker 3: I think most of this literature is really bad and
- 23:56Speaker 3: it is observational and not causal, and I have a
- 23:58Speaker 3: lot of complaints about it, and I've been practicing my complaints.
- 24:01Speaker 3: But before we get into them, I do think it's
- 24:05Speaker 3: worth talking like a little bit more. You alluded to
- 24:08Speaker 3: Cushings disease, but a little bit more about the places
- 24:13Speaker 3: where high cortisol can actually be very damaging.
- 24:17Speaker 2: Or we know that this is a this is a problem.
- 24:20Speaker 1: Yeah, we should talk about Cushing's disease because actually a
- 24:23Speaker 1: lot of the influencer work is taking what people see
- 24:28Speaker 1: in Cushions disease where cortisol levels are through the roof
- 24:32Speaker 1: and saying therefore, mildly elevated cortisol levels and normal people
- 24:36Speaker 1: also do this thing. And so so what Cushing's disease
- 24:39Speaker 1: is is a benign tumor, typically on the adrenal gland
- 24:43Speaker 1: that secretes cortisol. It is unregulated, so it's sitting there
- 24:48Speaker 1: and it's just secreting cortisols, secreting cortisols, secreting cortisol, and
- 24:51Speaker 1: that is quite bad for you. The syndrome of Cushing
- 24:55Speaker 1: syndrome is characterized by pretty dramatic moon faces. What they
- 24:59Speaker 1: call it the very round face that you may be
- 25:01Speaker 1: familiar with if you see people on very high dose
- 25:03Speaker 1: of other cotquot steroids like predmozone. Sorry about these terms,
- 25:07Speaker 1: but this is what the medical terms are. A buffalo hump,
- 25:09Speaker 1: which is like a collection of fat on the upper
- 25:12Speaker 1: part of the back at the bottom of the neck,
- 25:15Speaker 1: strea which are really violacious, like deep purple stretch marks
- 25:21Speaker 1: in the abdomen, a lot of accumulation of visceral fat, diabetes,
- 25:26Speaker 1: high blood sugar, and so on and so forth. The
- 25:29Speaker 1: treatment is removal of the cortisol secreting tumor, and.
- 25:34Speaker 3: I think it is it's actually very important to note
- 25:36Speaker 3: because some of the things we see in the sort
- 25:37Speaker 3: of wellness influencer claim space are things that seem like, well,
- 25:41Speaker 3: if you have this cushions disease, you will have this,
- 25:45Speaker 3: and therefore, if you have a mildly elevated level of
- 25:50Speaker 3: cortisol in the normal range, you also get less maybe less.
- 25:54Speaker 1: Belly fat, but still some belly fat, right right, And
- 25:57Speaker 1: that has that nice sort of like step by step
- 26:01Speaker 1: ring to it. But if you've been listening to Onelm's actually,
- 26:03Speaker 1: you know, you actually have to prove these things with data.
- 26:07Speaker 1: So let's talk about data. I mean, I you know,
- 26:09Speaker 1: there are clearly cases where cortisol high cortisol levels are
- 26:15Speaker 1: bad for you. I mean maybe the most dramatic one
- 26:17Speaker 1: is in sepsis in septic shock, where it is fairly
- 26:21Speaker 1: well established that if people are coming in with very
- 26:24Speaker 1: high cortisol levels in the setting of sepsis, they're more
- 26:26Speaker 1: likely to die. It's a nice study in PLUS one
- 26:29Speaker 1: in twenty nineteen that took one hundred and thirty nine
- 26:32Speaker 1: patients with severe sepsis or septic shock, and those who
- 26:36Speaker 1: had cortisol levels that were high by their definition had
- 26:41Speaker 1: a tenfold higher mortality risk. It's a pretty large effects size. Now, Emily,
- 26:47Speaker 1: that's not a causal step, as you said, that's observational.
- 26:51Speaker 1: So walk me through like why, yeah, is it the
- 26:53Speaker 1: cortisol that's bad or what are you thinking when you
- 26:55Speaker 1: hear Okay, high cortisol tenfold risk of death in septic shock.
- 26:58Speaker 3: Yeah, So I I think sort of two things in
- 27:01Speaker 3: that case, which will come up again later. So one
- 27:05Speaker 3: is that, yeah, this is not a randomized the cortisol
- 27:09Speaker 3: some people came in with a higher level of cortisol
- 27:11Speaker 3: than others. It seems plausible to me that that is
- 27:15Speaker 3: measuring something else about, you know, how stressful, like what
- 27:19Speaker 3: else is going on in your life? Or even like
- 27:22Speaker 3: how bad is this sepsis? I realize all sepsis is bad.
- 27:25Speaker 3: Sepsis is not good, but sort of like, could you
- 27:29Speaker 3: read this as this is is kind of a metric
- 27:31Speaker 3: itself of how much is the body struggling in other ways?
- 27:35Speaker 2: And this is just one measure of that.
- 27:37Speaker 3: I will say in this particular case, the fact that
- 27:39Speaker 3: the odds ratio is ten, which means like the mortality
- 27:42Speaker 3: risk is ten times as high, that's actually a quite
- 27:45Speaker 3: that's a very big effect. It is Therefore, the kinds
- 27:48Speaker 3: of biases I have in my mind, like differences in
- 27:51Speaker 3: other things that could be going on in people's lives
- 27:54Speaker 3: and so on, probably aren't driving a tenfold increase in mortality.
- 27:58Speaker 3: So the comp nation here of the particular outcome which
- 28:04Speaker 3: is so extreme and how large the effect size is,
- 28:07Speaker 3: would makes me more confident in that result, even though
- 28:09Speaker 3: I think it would be better to have a randomization.
- 28:11Speaker 3: Although this is a case in which I cannot imagine
- 28:14Speaker 3: how you would randomize people to different cortosol levels. That's
- 28:17Speaker 3: not really an available randomization, which is why we're going
- 28:20Speaker 3: to generally nature rely on observational data.
- 28:24Speaker 1: Yeah. Yeah. And for the medical people listening who trained
- 28:27Speaker 1: back when I did, there was a time when we
- 28:29Speaker 1: gave people cortisol or other gluca cortoicoids when they had
- 28:32Speaker 1: sepsis because we thought, oh, all this inflammation is the
- 28:36Speaker 1: bat like, their immune system's going crazy. We need to
- 28:39Speaker 1: suppress their immune system a little bit. That was standard
- 28:41Speaker 1: of care for a while. No longer really do that
- 28:43Speaker 1: except in rare circumstances, and so it is quite complicated.
- 28:47Speaker 1: And I think, you know, it's certainly possible that a
- 28:49Speaker 1: large amount of that observed effects size is just due
- 28:52Speaker 1: to the fact that really sick people have really high
- 28:54Speaker 1: cortosol potentially, but most people who are listening to us
- 28:58Speaker 1: are not current lead.
- 29:01Speaker 2: Shop. Yeah, stop listening. If that's you are hanging.
- 29:04Speaker 4: There, and.
- 29:07Speaker 1: Maybe we're the one thing keeping them, you know, seeing
- 29:09Speaker 1: in the hospital bed. We're not all right, we believe
- 29:12Speaker 1: in you.
- 29:13Speaker 3: Most people are worried about the idea that a chronically
- 29:19Speaker 3: elevated or frequently elevated level of cortisol or just having
- 29:23Speaker 3: high cortisol whatever people seem to mean by that, is
- 29:26Speaker 3: bad for some health outcome, like heart disease being the
- 29:30Speaker 3: sort of the one you should start with.
- 29:32Speaker 2: It's the one that comes up the most. And so
- 29:34Speaker 2: this is a place where there is some.
- 29:36Speaker 3: Data, and i want you to describe the data, and
- 29:38Speaker 3: then I'm going to tell you my feelings on it,
- 29:41Speaker 3: why it's wrong.
- 29:42Speaker 1: I'll set you up in the best way I know how. Okay,
- 29:46Speaker 1: I'm going to give you two studies here. One is
- 29:50Speaker 1: sort of a prototypical. There's other studies in this space
- 29:53Speaker 1: looking at urinary cortisol. Gosh, we didn't even mention that's
- 29:56Speaker 1: there's yet another place you can measure cortisol. You can
- 29:58Speaker 1: measure it in the urine and then the risk of
- 30:01Speaker 1: cardiovascular mortality. This was from the Journal of Clinical Endocritinology
- 30:04Speaker 1: and Metabolism. That's a good journal. Twenty ten, eight hundred
- 30:07Speaker 1: and sixty one participants above age sixty five. They got
- 30:10Speaker 1: twenty four hour urine cortisol levels at baseline, followed them
- 30:13Speaker 1: for six years. Over the course of that time, people
- 30:17Speaker 1: in the highest turtile, so the highest third of urinary
- 30:21Speaker 1: cortisol levels had five times the risk of dying in
- 30:23Speaker 1: cardiovascular disease, but there's no difference in depths from other causes.
- 30:29Speaker 1: So there's a big effect size fivefold from higher cortisol levels.
- 30:35Speaker 1: I told you I'd give you one other study just
- 30:38Speaker 1: to give you something to talk about. So nope, I'm not.
- 30:42Speaker 1: I'm going to wait on the Mendelian randomization because it's
- 30:45Speaker 1: going to require some explanations. So let's start with this.
- 30:47Speaker 1: My urinary cortisol is in the top third of people's
- 30:50Speaker 1: urinary cortisol. I have fivefold the risk of dying from
- 30:52Speaker 1: cardiovascular disease in the next six years. Sounds pretty bad.
- 30:55Speaker 1: Got to get my cortisol down, okay, I mean.
- 30:58Speaker 3: Look, here are some things that raise people's cortisol. Being poor,
- 31:04Speaker 3: working at night, having few resources, having a stressful family life,
- 31:09Speaker 3: having other diseases, things like that. All of those things
- 31:14Speaker 3: are independently associated with death from heart disease. We know
- 31:19Speaker 3: that like a million different ways, exercise causes you to
- 31:23Speaker 3: be less dying rate lowers your cortisol. Overall, all of
- 31:28Speaker 3: these things are going on in the background. And if
- 31:31Speaker 3: you look at the people in this study and you
- 31:33Speaker 3: look at the tersiles, they differ in a bunch of
- 31:36Speaker 3: different ways from each other, and it is therefore extremely
- 31:42Speaker 3: difficult to imagine that we are attributing this difference in
- 31:48Speaker 3: the risk of death to these levels of cortisol as
- 31:53Speaker 3: opposed to attributing them to these other things. Now, this
- 31:56Speaker 3: is a case in which actually the whole thing is
- 31:58Speaker 3: very complicated, because, well, maybe it's these other things raising
- 32:00Speaker 3: your cortisol, which is then causing you to you know,
- 32:04Speaker 3: have a higher risk of death.
- 32:05Speaker 2: That's an interesting mechanism.
- 32:07Speaker 3: But if you ask, like, what's the act like, what's
- 32:09Speaker 3: the action item here, what's the like thing that would
- 32:12Speaker 3: it's changing these other things.
- 32:13Speaker 2: It's not like if you gave someone.
- 32:15Speaker 3: A shot that magically lowered their cortisol that would have
- 32:18Speaker 3: this positive impact on them. These results are also this
- 32:21Speaker 3: sample is quite small, not that many people died, which
- 32:25Speaker 3: is good, and the therefore this sort of hazard ratio
- 32:29Speaker 3: of five is like incredibly noisy. It's consistent with an
- 32:32Speaker 3: effect that's two, it's consistent with an effect of thirteen times,
- 32:35Speaker 3: which is definitely not true. It's just this is a
- 32:38Speaker 3: statistically noisy, very potentially biased effect.
- 32:44Speaker 2: I just I don't think we learn anything from studies
- 32:48Speaker 2: like this. I just think we learned nothing.
- 32:50Speaker 1: So I completely agree that there's all this stuff that
- 32:55Speaker 1: can affect your cortisol that might also independently affect your
- 32:58Speaker 1: risk of death. Right we know in America at least
- 33:01Speaker 1: being poor dramatically increases your risk of dying from Christ and.
- 33:04Speaker 2: Also dramatically increases so yeah.
- 33:07Speaker 1: So so okay, that's classic confounding. The problem is, you know,
- 33:11Speaker 1: we all love a randomized trial, but no one's going
- 33:13Speaker 1: to do a randomized trial of like supplemental cortisol on
- 33:16Speaker 1: people that's not going to happen. Probably would be considered unethical.
- 33:20Speaker 1: So we're left with some other options, and I think
- 33:24Speaker 1: I think we need to talk about Mendelian randomization. Okay,
- 33:27Speaker 1: so let's put on our genetic hats for a second.
- 33:31Speaker 1: I sort of believe in Mendelian randomization as an approach,
- 33:35Speaker 1: and Emily, I think you are more skeptical of it.
- 33:37Speaker 1: So I'm gonna let me tell you how I view it,
- 33:40Speaker 1: and then you tell me why I'm wrong. Okay, here's
- 33:42Speaker 1: the idea. There are certain genes that increase the amount
- 33:48Speaker 1: of cortisol you make independent of other things. Genes that
- 33:52Speaker 1: have to do with hormone synthesis and stuff, and everyone
- 33:54Speaker 1: has little variations in their genes, and some are just
- 33:57Speaker 1: a bit more active than others, and so all else
- 33:59Speaker 1: being equal, there are people who genetically live at a
- 34:04Speaker 1: higher cortisol level than a similar person who had a
- 34:08Speaker 1: different genetic background, so you know, and this is true
- 34:11Speaker 1: of everything, not just cortisol. Right, Like, there's some people
- 34:13Speaker 1: just genetically have a higher LDL than other people, and
- 34:16Speaker 1: some people have genetically lower LDL. Okay, because your genetics
- 34:20Speaker 1: are assigned at birth, not no, at conception. That exposure
- 34:28Speaker 1: happens before you know that you're poor, before you know
- 34:33Speaker 1: you have stress in your life, before anything else, it
- 34:35Speaker 1: cannot be related to that. The genetics are not related
- 34:38Speaker 1: to those things. Being poor doesn't change your DNA, right,
- 34:43Speaker 1: And therefore we can use those genetic signals and say, Okay,
- 34:46Speaker 1: here's a person whose genes have them exposed to a
- 34:50Speaker 1: higher level of cortisol than they otherwise would have been
- 34:54Speaker 1: given everything that's going on in their life. And here's
- 34:56Speaker 1: a person whose genes have their cortisol lower than they
- 34:59Speaker 1: otherwise would have been, giving everything that's going on in
- 35:02Speaker 1: our life. And if the person with the genes that
- 35:04Speaker 1: predispose them to high cortisol has a higher risk of
- 35:07Speaker 1: cardiovascular disease. Then the person whose genes predisposed them to
- 35:10Speaker 1: low cortisol. I conclude, therefore, there is a causal link
- 35:15Speaker 1: between cortisol level and cardiovascular disease.
- 35:19Speaker 3: The term Mendilion randomization implies that something is being randomized,
- 35:25Speaker 3: and so I think when we think about this technique,
- 35:28Speaker 3: we want to think about the word random. So what
- 35:34Speaker 3: you are suggesting is that the genes are allocated randomly,
- 35:39Speaker 3: that when you are given genes are there's a piece
- 35:42Speaker 3: of the genetics that are coming randomly to you. That
- 35:48Speaker 3: is not true when comparing across people in the population overall.
- 35:52Speaker 3: So let me give you a more like direct example
- 35:55Speaker 3: of this. Imagine that instead of cortisol, we were thinking
- 35:58Speaker 3: about eye color and you said, there's a gene that
- 36:02Speaker 3: determines your that determines your eye color. In fact, there
- 36:04Speaker 3: is a gene that determines your eye color. There's a
- 36:06Speaker 3: set of genes. We understand about how those work, but
- 36:10Speaker 3: it is not when we look across the population, those
- 36:14Speaker 3: genes are not randomly distributed. It's not like randomly when
- 36:17Speaker 3: you're conceived you are given one of the eye color genes.
- 36:21Speaker 3: It's random only conditional on the genes.
- 36:23Speaker 2: That your parents have.
- 36:25Speaker 3: So you have a set of parents, and you have
- 36:28Speaker 3: your mom has a set of twenty three chromosomes. She
- 36:31Speaker 3: has two copies of each, and at conception in the egg,
- 36:36Speaker 3: you get one of those and which one you get
- 36:38Speaker 3: is random. But who your mother is, the genetics that
- 36:43Speaker 3: she starts with is not random. So when we talk
- 36:47Speaker 3: about Mendolian randomization, there's something cool, a cool idea in here.
- 36:51Speaker 3: I want you to imagine two children born to the
- 36:54Speaker 3: same set of parents, and mom has two copies of
- 36:59Speaker 3: each chromosome, and on one of those chromosomes she's got
- 37:01Speaker 3: like the high cortisol gene, and on the other copy
- 37:05Speaker 3: she's got the low cortisol gene. And her children, let's
- 37:09Speaker 3: say one of them gets the high cortisol, one of
- 37:12Speaker 3: them gets the low cortisol. That's random, and so then
- 37:15Speaker 3: we have two siblings who are effectively everything is, you know,
- 37:20Speaker 3: the same, except that in this case this particular thing
- 37:23Speaker 3: is randomly allocated. Wait, and so you could then get
- 37:28Speaker 3: many sibling pairs like that, and say, conditional on your family,
- 37:32Speaker 3: controlling for your parentage. Comparing you to your siblings. We're
- 37:38Speaker 3: going to see whether the sibling who was randomly allocated
- 37:41Speaker 3: the high cortisol gene has worse outcomes than the sibling
- 37:45Speaker 3: that was not randomly allocated. That's a really cool idea
- 37:49Speaker 3: that uses genetics and randomizes.
- 37:52Speaker 1: Do you agree? Yeah? All I wanted to say was
- 37:55Speaker 1: that in my mind, one of these kids is named
- 37:58Speaker 1: Gene and the other is named.
- 38:01Speaker 2: I love that so much. Okay, but what okay?
- 38:05Speaker 3: So that technique, that technique works like, that works sort
- 38:10Speaker 3: of in concept the way I've described it, and there
- 38:12Speaker 3: are some actually some issues with using that technique in practice,
- 38:15Speaker 3: but at least in principle, there is a real randomization there.
- 38:21Speaker 2: Here is the problem.
- 38:22Speaker 3: The studies that are being done that are using a
- 38:25Speaker 3: technique they are referring to as Mendillion randomization do not
- 38:29Speaker 3: actually do what I just described. Instead, what they do
- 38:33Speaker 3: is they don't look within sibling pairs. They look just
- 38:37Speaker 3: across people in the population. And that is ridiculous because
- 38:42Speaker 3: genetics are not randomly allocated across people in the population.
- 38:46Speaker 3: I mean, an equivalent thing is if you said, well,
- 38:49Speaker 3: I'm interested in the impact of race on something, and
- 38:52Speaker 3: I don't think I can just look at people's race,
- 38:54Speaker 3: because that's confounded with all kinds of other things. But
- 38:56Speaker 3: I'm going to look at a gene for skin color
- 38:58Speaker 3: and I'm going to relate that to the out Well,
- 39:00Speaker 3: that's stupid, that's not like.
- 39:02Speaker 2: Doesn't make any sense. It doesn't work.
- 39:04Speaker 3: And so this this technique is not being it's not
- 39:07Speaker 3: that it's conceptually poor, it's being used in a way
- 39:10Speaker 3: that makes no sense.
- 39:12Speaker 1: Well, so the there is a caveat to Mendelian randomization.
- 39:16Speaker 1: So to take your skin color example, which says that
- 39:18Speaker 1: in order to use this technique, you have to show
- 39:21Speaker 1: that the gene is associated with the phenotype. Right, So
- 39:24Speaker 1: the gene is associated with skin color, let's say, and
- 39:28Speaker 1: the gene is associated with the outcome, but the gene
- 39:32Speaker 1: is not associated with the outcome through any plausible path
- 39:37Speaker 1: outside of the phenotype. So there is like some statistical
- 39:42Speaker 1: testing you can may for that.
- 39:43Speaker 2: Yeah, that's called the exclusion restriction.
- 39:45Speaker 3: And in the cases that you've described, where we're comparing,
- 39:49Speaker 3: say to people with different genetics across different families, where
- 39:53Speaker 3: for example, one of them is born to a set
- 39:56Speaker 3: of parents who have high cortisol and one of them
- 39:59Speaker 3: is born to a set of parents with low cortisol.
- 40:01Speaker 3: Now your exclusion restriction is failed, and so that just
- 40:03Speaker 3: doesn't work. So I think you're right, there is a
- 40:07Speaker 3: thing and it's totally failing, and these guys don't seem
- 40:09Speaker 3: to understand that.
- 40:11Speaker 2: I just don't understand. I fundamentally perry.
- 40:13Speaker 3: This is like drives me crazy because people in medicine
- 40:17Speaker 3: use this technique all the time, and I just think
- 40:19Speaker 3: they don't understand what they're doing, and I can't understand
- 40:21Speaker 3: why they don't understand.
- 40:23Speaker 1: Let me give you the results of the cortisol Mendelian
- 40:25Speaker 1: randomization because maybe this is a moot point. Okay, So
- 40:29Speaker 1: in the observational framework, we've seen that a high level
- 40:33Speaker 1: of cortisol increases your risk of cardiovascular death by five
- 40:36Speaker 1: hundred percent. Okay. In the Mendelian randomization analysis, genes predisposing
- 40:41Speaker 1: high cortisol increase the risk of cardiovascular death by eight percent.
- 40:46Speaker 2: Right, I mean, okay.
- 40:48Speaker 3: So one thing is if you think what Mendelian randomization
- 40:52Speaker 3: is doing is fixing your causality problem, then I think
- 40:56Speaker 3: what you would say, Okay, now we've got a better result,
- 40:59Speaker 3: and it's basically zero like it's it does basically doesn't.
- 41:02Speaker 1: Matter, does not suggest causality.
- 41:03Speaker 3: I will say, I think counter counter example, as I've noted,
- 41:08Speaker 3: I don't think the Mendelian randomization really makes any sense
- 41:11Speaker 3: at all.
- 41:12Speaker 2: And part of the reason that the effect I think
- 41:15Speaker 2: is much.
- 41:15Speaker 3: Smaller is because the genes are identifying have very little
- 41:20Speaker 3: predictive power on actually having high cortisol, and so like
- 41:25Speaker 3: just these these genes are not have very high penetrants,
- 41:28Speaker 3: and so this may be failing and giving you a
- 41:32Speaker 3: very small number for reasons that kind of have nothing
- 41:34Speaker 3: to do with getting rid of bias. They may just
- 41:37Speaker 3: be generating noise. I hate this technique.
- 41:39Speaker 2: I understand that I'm being like and talking about I hate.
- 41:45Speaker 1: I just that's fine. We can't randomize people to high cortisol.
- 41:49Speaker 1: We can't supplement them with cortisol or placebo, so we're stuck.
- 41:53Speaker 1: We have to make some inferences. But I will say
- 41:56Speaker 1: that based on this data, it's there's not a compelling
- 41:59Speaker 1: argument high cortisol level in and of itself is causal
- 42:02Speaker 1: of cardiovascular disease.
- 42:04Speaker 2: I totally that. I think we totally agree.
- 42:07Speaker 3: I think your question about give me a better technique
- 42:09Speaker 3: is an interesting one. I mean, I do think a
- 42:12Speaker 3: true Mendelian randomization with a sort of a sibling pairastudy
- 42:16Speaker 3: would be an interesting thing to explore. It could have
- 42:19Speaker 3: some other problems, but I think that would be something
- 42:20Speaker 3: interesting to explore. I agree this is a very difficult problem.
- 42:25Speaker 3: I think one thing you could imagine randomizing if you
- 42:28Speaker 3: sort of at least in a short term way, is
- 42:32Speaker 3: you know, some of the kind of like behavioral techniques
- 42:35Speaker 3: that might lower people's cortisol, like meditation. You can imagine
- 42:39Speaker 3: running a study where you're like one group gets like
- 42:41Speaker 3: a lot of meditation support or some other you know,
- 42:44Speaker 3: therapy something that would lower their cortisol.
- 42:47Speaker 2: It probably have other effects, so.
- 42:48Speaker 3: It's not like a great study, but I you know,
- 42:51Speaker 3: like it's something like that to try to affect people's cortisol.
- 42:54Speaker 2: I agree, we're not going to find anything, but doesn't
- 42:56Speaker 2: mean it's not interesting to.
- 42:58Speaker 1: Try to at least.
- 42:59Speaker 3: Luck. All right, let's get so sorry, I got so
- 43:02Speaker 3: exercise guy. I feel like people are going to be like,
- 43:04Speaker 3: why are you so exercised about this? But it's like,
- 43:07Speaker 3: this is my job, This is like a thing, this
- 43:09Speaker 3: is like the core of my of my like professional
- 43:12Speaker 3: life other than parenting. Writing is like statistical methods.
- 43:15Speaker 1: What you guys don't know is that Emily, Emily's first
- 43:20Speaker 1: boyfriend was a Mendelian randomization study.
- 43:23Speaker 4: So okay, I want to move rather quickly through the
- 43:29Speaker 4: other basically true stuff that the other stuff.
- 43:34Speaker 1: That people say that high cortisol does. If we're going
- 43:36Speaker 1: to write off cardiovascular disease, and again, guys, we're not
- 43:39Speaker 1: saying that there's no association between higher cortisol levels and
- 43:42Speaker 1: these things. We're asking is it the cortisol not the
- 43:45Speaker 1: like life stress and the other stuff. So I think
- 43:48Speaker 1: you know a big one is diabetes metabolic disease, right, Like,
- 43:52Speaker 1: we we certainly know that people with cushions syndrome much
- 43:55Speaker 1: high risk of diabetes. We know that when you put
- 43:57Speaker 1: people on steroids like prednozone or hyd you courtizona, their
- 44:01Speaker 1: blood sugar goes up. I was surprised here, Emily, Like,
- 44:05Speaker 1: there's a nice meta analysis of twenty one studies. This
- 44:08Speaker 1: is appearing in psycho Neeuroendrochronology. In twenty eighteen, eleven thousand
- 44:14Speaker 1: people or almost twelve thousand people, no significant difference in
- 44:17Speaker 1: basil cortisol levels between subjects with and without the metabolic syndrome,
- 44:21Speaker 1: which I just wouldn't have. And that's like, that's not
- 44:23Speaker 1: even a causal study. It's just I mean, I think
- 44:26Speaker 1: there's no link.
- 44:27Speaker 2: What's so interesting there is?
- 44:28Speaker 3: I might have I would have thought that that we
- 44:32Speaker 3: would see an association there just because of all these
- 44:34Speaker 3: other factors.
- 44:35Speaker 2: Totally, But it seems like even you know.
- 44:38Speaker 1: Even the confounding can't and the confounding can't.
- 44:41Speaker 2: Get you there somehow. Yeah, maybe that's that's hard to measure.
- 44:45Speaker 1: Let's do stubborn belly fat?
- 44:48Speaker 2: Yes, so much of it? Okay, how do I.
- 44:52Speaker 1: Have so much stubborn belly fat? I don't think you too.
- 44:54Speaker 2: It's so stubborn. I am always arguing with it. It's
- 44:57Speaker 2: always making these terrible points.
- 44:59Speaker 1: Are Producer Tamar just rolled her eyes like Emily's saying
- 45:03Speaker 1: she has belly fat.
- 45:04Speaker 3: Enoise describe stubborn Well, okay, anyway, I as a middle
- 45:10Speaker 3: aged man, stubborn belly fat is I get it.
- 45:12Speaker 1: It's stubborn because it's like I work out, I try
- 45:14Speaker 1: to eat right, and it's still there and that's annoying.
- 45:17Speaker 1: So I did look into this for us once again
- 45:21Speaker 1: in Cushing syndrome and Cushing's disease, there is a substantial
- 45:25Speaker 1: increase in visceral outipost tissue. That's what belly fat is,
- 45:29Speaker 1: as opposed to subcutaneous fat, which is kind of all
- 45:32Speaker 1: over your body. Belly fat is visceral fat, and it's
- 45:35Speaker 1: not good for you. Higher amounts of visceral fat are
- 45:38Speaker 1: associated and potentially causally with cardiovascular disease. But in a
- 45:46Speaker 1: study pering clinical endochronology in twenty twenty four, they looked
- 45:50Speaker 1: at visceral fat and subcutaneous fat among people just regular
- 45:54Speaker 1: joes with varying cortisol levels, and there was no association
- 45:57Speaker 1: between higher cortisol level in the non pathologic range, in
- 46:01Speaker 1: the non Cushing's disease range, and belly fat. So that's
- 46:05Speaker 1: not it, folks.
- 46:06Speaker 3: I also think it's worth saying, like when people are
- 46:09Speaker 3: chronically stressed, it actually isn't.
- 46:12Speaker 2: We said this at the topics.
- 46:13Speaker 3: We're saying again, it's not that chronic stress means you
- 46:15Speaker 3: always have a high cortisol level. It actually means your
- 46:18Speaker 3: cortisol is very flat, as opposed to moving up and
- 46:21Speaker 3: down like it's sort of supposed to typically, And so
- 46:24Speaker 3: like your cortisol is supposed to be responsive to like
- 46:26Speaker 3: events and to the day, which of course is evolutionary
- 46:29Speaker 3: valuable because you want to really be able to respond
- 46:32Speaker 3: when the tiger.
- 46:33Speaker 2: When the tiger comes.
- 46:34Speaker 3: When people are chronically stressed, they can get a sort
- 46:38Speaker 3: of flattening of the cortosol, but it's not that it's higher,
- 46:40Speaker 3: and so this sort of whole narrative is kind of
- 46:43Speaker 3: con Yeah, it.
- 46:43Speaker 1: Can even burn out. So there's some nice studies in PTSD,
- 46:46Speaker 1: in patients with PTSD that actually shows your typical patient
- 46:49Speaker 1: with PTSD has lower cortisol levels than controls who don't
- 46:54Speaker 1: have trauma. So yeah, this whole idea that like, your
- 46:57Speaker 1: cortisol is so high and because you're so stressed, if anything,
- 47:01Speaker 1: it's blunting the cortisol response, or your cortosol might even
- 47:04Speaker 1: be low.
- 47:06Speaker 3: So you don't need to detox your cortisol, not that
- 47:08Speaker 3: we have any Like people will sell you a lot
- 47:11Speaker 3: of stuff gum ease.
- 47:12Speaker 1: Yeah, n well, yeah, I mean I did, I did
- 47:15Speaker 1: look into it in case people want to make their cortisol.
- 47:18Speaker 1: You know what, there are some things that will make
- 47:19Speaker 1: your cortisol lower that I think are good for you anyway,
- 47:22Speaker 1: So there's a pretty large meta analysis of randomized control
- 47:26Speaker 1: trials you talked about, you know, randomizing people to interventions
- 47:30Speaker 1: to lower cortisol, which of course have off target effects.
- 47:33Speaker 1: This is once again psycho Neeurontochronology twenty twenty four or
- 47:36Speaker 1: fifty eight randomized trials just about thirty five hundred patients
- 47:39Speaker 1: looking at different ways to reduce cortisol levels, and mindfulness,
- 47:43Speaker 1: meditation relaxation techniques both reduce cortisol levels by about a
- 47:51Speaker 1: third or so, not bad. Interestingly, the studies of yoga
- 47:56Speaker 1: and tai chiet didn't have a significant effect, and the
- 47:59Speaker 1: talk therapies like cognitive behavioral therapy and counseling did not
- 48:01Speaker 1: have a significant effect.
- 48:03Speaker 3: So meditation, Yeah, exercise is good for your cortisol lowers
- 48:09Speaker 3: your cortisol.
- 48:10Speaker 2: We also see that in randomized control trials.
- 48:13Speaker 1: Yep, absolutely exercise and we've hit on the several times.
- 48:16Speaker 1: But sleep, you guys, especially especially if you want to
- 48:20Speaker 1: maintain that diurnal variation, which does appear to be an
- 48:23Speaker 1: important thing for your overall health. Getting adequate amounts of
- 48:27Speaker 1: sleep gets the cortisol into the right place at the
- 48:31Speaker 1: right time.
- 48:31Speaker 3: So is it worth I think an interesting question is
- 48:34Speaker 3: it worth measuring your cortisol at all? So we just
- 48:37Speaker 3: gave you know there are these are recommendations too that
- 48:40Speaker 3: will reduce your cortisol, but also things which you should
- 48:44Speaker 3: probably be doing for a general like health maintenance regardless.
- 48:49Speaker 3: Would you recommend someone measure their cortisol.
- 48:52Speaker 1: If they had moon faces, a buffalo hump, or a
- 48:55Speaker 1: violaceous strea, I would recommend that they have cortisol levels measured.
- 49:00Speaker 2: Do you want to know what my cortosol level is?
- 49:01Speaker 3: Because I looked it up while we were here, because
- 49:04Speaker 3: I had it measured in the last time I had
- 49:05Speaker 3: a blood test.
- 49:06Speaker 1: What time of day was it.
- 49:09Speaker 2: It was in the morning.
- 49:11Speaker 1: It was fifteen micrograms pertest leader nineteen.
- 49:16Speaker 2: It only got in in the sufficient range for.
- 49:22Speaker 1: We should say, I can't believe yeah, sufficient, You know
- 49:26Speaker 1: you die without enough cortisol, right, Like that's the other
- 49:29Speaker 1: The flip side of this is that your adrenal glands
- 49:32Speaker 1: can stop producing cortisol. This is called Addison's disease, which
- 49:35Speaker 1: JFK had, and it causes like severe hypotension, sodium wasting death.
- 49:41Speaker 1: You need to supplement that's bad too. So I think
- 49:44Speaker 1: the cortisol is just like not something if you're into
- 49:47Speaker 1: interested in your health and wellness, it's just not worth
- 49:49Speaker 1: your time. It's like, don't you're not going to change
- 49:52Speaker 1: your life based on it. And yes you should destress,
- 49:55Speaker 1: but not because of cortisol.
- 49:57Speaker 3: Look, I think every time we talk about hormones, I
- 50:01Speaker 3: am more and more impressed with the endocrine system. I
- 50:05Speaker 3: feel like, you know, the human endocrine system is so
- 50:09Speaker 3: like tight, and it's so well thought out, and there's
- 50:14Speaker 3: so much of the wellness space that's about like give
- 50:17Speaker 3: yourself more of this hormone and more of that homer
- 50:19Speaker 3: and do this, and most of the time, like your endocrinsism,
- 50:21Speaker 3: like it's thinking about that, like it thought about when
- 50:23Speaker 3: the cord sho should be, when it should be low,
- 50:25Speaker 3: like how much you need. It's like estrogen, Like we're
- 50:28Speaker 3: all kind of moving moving together, and I just I
- 50:31Speaker 3: don't think it's a system we want to be messing
- 50:33Speaker 3: with too much.
- 50:35Speaker 1: With the exception of hormone replacement therapy and with the exceptional.
- 50:38Speaker 3: Yeah, yeah, okay, there are some things, but like like
- 50:42Speaker 3: our tendency to want to get inside the endocrine system
- 50:45Speaker 3: and mess around with it, I think is over. I
- 50:48Speaker 3: think we're doing we're doing too much of that outside
- 50:51Speaker 3: of I agree hormone replacement.
- 50:52Speaker 1: Yeah yeah. Cortisolt too high is bad, Cortisol too low
- 50:55Speaker 1: is bad. It needs to have a specific pattern. You're
- 50:58Speaker 1: not going to get this right with like ashwaganda, which
- 51:00Speaker 1: does lower your cortisol a little bit, by the way,
- 51:02Speaker 1: but like this is one. Trust your body a little
- 51:05Speaker 1: bit and be zen.
- 51:06Speaker 3: Trust your body, but don't trust Mendelian randomization because it's stupid.
- 51:14Speaker 1: It can be done very well.
- 51:16Speaker 2: It can be, but it's not okay. Enough of that
- 51:19Speaker 2: for me, all right, Perry, smash your pass cortisol.
- 51:23Speaker 1: I mean I'm a pass in terms of cortisol as
- 51:26Speaker 1: a wellness metric. Obviously I love the hormone. I die
- 51:29Speaker 1: without it, so do you. But I'm a past Emily
- 51:32Speaker 1: Smasher pass.
- 51:33Speaker 3: I am a pass on anything that involves detoxing, retoxing,
- 51:38Speaker 3: changing gummies adapt to this and that. Just trust your
- 51:43Speaker 3: endocrine system unless you have a buffalo and then get
- 51:47Speaker 3: it looked at.
- 51:48Speaker 1: All Right, that's it for cortisol. Your mail bag question
- 51:50Speaker 1: of the Week after the break.
- 51:57Speaker 2: Hi, Emily and Perry. This is celestin Detroit. My question
- 52:00Speaker 2: is more personal to both of you.
- 52:02Speaker 3: Is there anything that you felt certain about like ten
- 52:05Speaker 3: years ago that now you look back on and cringe.
- 52:08Speaker 2: We all have them, and I'm dying to know yours. Thanks.
- 52:13Speaker 1: Oh, this is such a good question. I'm sure there
- 52:17Speaker 1: are many things that I've suppressed, and I have convinced
- 52:21Speaker 1: myself that I never believed that really I did. But
- 52:24Speaker 1: the one I am quite sure I believed strongly. And
- 52:27Speaker 1: I think I'm going to just cheat a little bit
- 52:29Speaker 1: and say this was more like fifteen years ago, maybe
- 52:31Speaker 1: even pushing twenty years ago. But I was a hardcore
- 52:37Speaker 1: fluid resuscitation vigilante when I was in medical training. So
- 52:41Speaker 1: when someone came into the ICU with sepsis, I was
- 52:44Speaker 1: it was like a contest, like how much IVY fluid
- 52:47Speaker 1: can I put into this person in the next twelve hours?
- 52:50Speaker 1: And back then, we thought this was the right thing
- 52:54Speaker 1: to do. This totally makes me cringe now, like there's
- 52:56Speaker 1: been a lot of evidence in the past twenty years
- 52:59Speaker 1: that suggests that overly aggressive fluid resuscitation can cause major
- 53:03Speaker 1: problems down the road, and you know, people get volume
- 53:05Speaker 1: overloaded and their lungs don't work anymore and stuff like that.
- 53:08Speaker 1: But it was like it used to be a contest
- 53:10Speaker 1: among the residents, like I gave that guy fifteen liders
- 53:13Speaker 1: last night and like high five, like, yeah, that's how
- 53:15Speaker 1: you treat sepsis. And I cringe a little bit thinking
- 53:18Speaker 1: about that. Now, why you am.
- 53:22Speaker 2: I that's amazing.
- 53:23Speaker 3: Mine is more Mine is more personal. It actually vaguely
- 53:27Speaker 3: relates to to cortosol. So I used to be very
- 53:31Speaker 3: sure that you should exercise in the morning before you eat,
- 53:34Speaker 3: and that you should like not eat anything before you
- 53:36Speaker 3: you should like exercise fasted. But it turns out that's
- 53:40Speaker 3: really stupid and it's really bad for your cortisol. I
- 53:45Speaker 3: think it raises your cortisol a lot to exercise fasted,
- 53:50Speaker 3: and I don't do that anymore. And I think it
- 53:54Speaker 3: was part of this space of like, you know, like
- 53:57Speaker 3: diet culture that I find now very cringey.
- 54:00Speaker 1: It's okay, we're all entitled to change.
- 54:03Speaker 3: I can't believe you guys were high fiving. That's like,
- 54:06Speaker 3: that's so nerdy and weird. Oh yeah, it makes me Yeah, okay,
- 54:14Speaker 3: I have feelings. I'm not going to comment.
- 54:17Speaker 1: Thanks.
- 54:20Speaker 2: All right, that's it for us today.
- 54:23Speaker 3: Stick with us next week when we'll ask what's the
- 54:25Speaker 3: deal with pregnancy brain and we'll have a special guest.
- 54:29Speaker 3: Wellness Actually is produced in association with iHeartMedia. Our senior
- 54:33Speaker 3: producer is Tamar Avisheid. Our executive producer at iHeart is
- 54:37Speaker 3: Jennifer Bassett. Our theme music is by Eric Deutsch, and
- 54:41Speaker 3: our content is for educational purposes only.
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- 55:01Speaker 1: from our mailbag or suggest a topic for a future show.
- 55:05Speaker 2: We'll let the influencers have the last word.
- 55:07Speaker 5: When your cortisol levels are elevated, you can hang on
- 55:09Speaker 5: to a lot of fat around your middle and this
- 55:10Speaker 5: can be really frustrating because it seems like you're doing
- 55:13Speaker 5: everything right, but it's not budging. The first thing I
- 55:15Speaker 5: want you to do is get rid of the high
- 55:17Speaker 5: intensity interval training. The second thing is intermittent fasting.
- 55:20Speaker 2: Get rid of it.
- 55:21Speaker 5: Eat thirty grams of protein within thirty minutes of waking up.
- 55:24Speaker 5: And the third one is the least fun, and that
- 55:27Speaker 5: is to stop drinking coffee first thing in the morning
- 55:29Speaker 5: on an empty stomach.
- 55:31Speaker 2: This third one might piss you off.