Episode #369: The 2025 Blood Pressure Update

25:29I don't actually know what the committee, you know, how they kind of arrived at this clarification. But to me, it seems reasonable. Yeah, I agree. And I like that they put this kind of caveat or at least the time point on there, because what you sometimes see is if you follow, you know, maybe a young person who's seen in a primary care clinic, they're not necessarily seen terribly frequently, especially if they don't have a ton of medical problems. And so maybe they come in and they have a concerning, you know, maybe mildly, moderately elevated blood pressure at one of their visits. And maybe the doc says, yeah, let's just like, you know, do some lifestyle changes, heavy air quotes around that, whatever that counseling actually looks like for that person.

26:08and then I'll see you in six months, maybe. And maybe that person doesn't actually come back for their six month appointment. And then they come back a year later, also maybe. And a year later, their blood pressure is still elevated or maybe they're, you know, maybe they're 20s or 30s and they don't actually see a doctor every year. And so then two years, three years, five years later, they come back. That's years worth of exposure to unnecessarily elevated blood pressure that has not been kind of controlled. And yes, in that short two, three, five year time period, their risk of a stroke is not going to be massively elevated, but that cumulative exposure across the lifespan is the thing that does drive long-term risk.

26:45And so this is a period of time where we do have more opportunity. And so when I have these kinds of conversations with folks, I give them often a couple of different options. I often have a conversation about, here are some of the specific lifestyle things that if we do them, here's the timeline on which I would actually expect to see blood pressure improvements. And so if somebody goes all out with all the behavior change stuff, maybe they reduce their alcohol intake, improve their sleep, exercise, take a few inches off their waist measurement, adjust their diet to promote a healthier dietary pattern, their blood pressure is going to come down in a matter of, you know, days to weeks, I would expect to see that, right?

27:22It's not going to take six months to see that. If somebody is going a little bit more gradually, maybe single behavior change at a time, it might take a little bit longer. But I'm not going to say, hey, let's do these things. And then I'll see you in a year or something like that. Or alternatively, what we could do is to spare you that exposure. We could start a super low dose of a medicine now. And then if we end up seeing that your blood pressure is coming down well into the normal range or even starting to dip a little bit lower than that, then we can just come off the medicine later and we will have avoided this unnecessary exposure to elevated blood pressure.

27:52And so we work through that decision-making process kind of together. And patients will opt for different things based on their preferences and things like that. Yeah, that's actually a study I would like to see. something large, hundreds of thousands of patients where, you know, they're like age match, generally, generally match for like demographics and other information. And then half of them get sort of early medication exposure. Sure. And the other are like, oh, we're going to let this ride for a few months while we initiate lifestyle stuff. And then hopefully you come back and we get a get a measurement.

28:25I would be curious, like if you took that study, that that that those groups and you followed them for 10 years, 20 years. Is there a difference? Because if you see a clear difference, you're like, well, shoot, maybe we shouldn't do this like early medication if there's no real benefit. Or if there is an apparent benefit, maybe you don't do this sort of like, let's do the lifestyle stuff first and kind of piecemeal it that way. Yeah, I think that that's a that would be a study that would be ideal to have. I don't envision us getting something like that. And ultimately, it's also going to be a matter of degree.

28:55And so I think that there would need to be some fancy statistical analysis that is above our heads to determine basically, you know, I guess if you think about blood pressure exposure as this area under the curve type cumulative thing over the lifespan, how much or what is the kind of spectrum of risk reduction based on how much of that area under the curve lowering that you get? that was a very confusing way of explaining what I'm trying to say is like, how much did you lower the person's blood pressure upfront? And for how long versus not doing that? And then what was the impact on their risk, say 10 years, 20 years, 30 years later, I don't envision we're going to get that study.

29:35But that would indeed be interesting to see. Yeah, hey, look, if you're a researcher, just do that. We don't need another creatine study, we need this. How about that? All right, Well, look, after the break, we'll be back to talk about new blood pressure screening guidelines, Apple Watch's hypertension detection feature, and more. This podcast is brought to you by FIGS. At Barbell Medicine, we spend a lot of time talking about what it takes to build a body that can handle high-level performance, but the recovery and health side is just as critical. Now, over the last six years, an incredible team of healthcare professionals did something that most people thought was impossible.

30:07They helped rebuild the body of legendary Olympian Lindsey Vonn after a series of devastating injuries. And now, she's actually headed back to the 2026 Winter Games in Milan, and she's ready to break records once again. This February, Lindsey's team and the entire USA medical team will be wearing figs, and you can rock their official uniform too. The new Team USA collection from Figs is engineered with Fiber X. It's their most durable fabric yet. It really is setting a new gold standard for high-level performance scrub wear because it's lightweight, it's breathable, and it's ultra-resilient for those long shifts.

30:37And of course, the style comes in red, white, and blue. Now, if you want the gear that the medical team behind the world's best athletes are wearing, check out the limited edition Team USA collection. You get 15 % off your first order at wearfigs.com with code FIGSRX. That's wearfigs.com, code FIGSRX. All right, we're back here on the Barbell Medicine Podcast. We're talking about blood pressure once again because there have been a lot of updates. These recent guidelines have changed some new guidance on what to do for individuals with not only high blood pressure screening and also how to treat individuals with elevated blood pressure.

31:13So let's get back to this screening discussion. This was interesting. Now, it's interesting to me as just like a general physiology sort of nerd. I'm like, oh, this is like way more prevalent than we thought. And the fact that it's been called like the silent epidemic of secondary hypertension, I did not know that. But it is interesting. So the new clinical practice guidelines from not only the Endocrine Society but also, you know, there's some guidance in the AHA document. The Endocrine Society, though, goes one step further. They say, look, we suggest that all individuals with hypertension be screened for primary aldosteronism by measuring a plasma aldosterone concentration and renin concentration activity and determining the aldosterone to renin ratio.

32:00Potassium should also be assessed not for screening itself, but to aid in the accurate interpretation of aldosterone. Now, look, if you haven't taken physiology in the last few years and all these words are a little foreign to you, here's the overview here. So one of the ways that the body controls blood pressure is by what's known as the renin angiotensin aldosterone system. Now, renin is a hormone produced by the kidneys. It is released in response to reduced blood pressure, which triggers the adrenal glands. They sit on top of the kidneys. They produce this other hormone called aldosterone.

32:34And aldosterone's job is to make the kidneys retain salt and water, which raises blood pressure and blood volume. Now, in primary aldosteronism, the adrenal glands overproduce aldosterone from some mechanism. This leads to sustained high blood pressure that doesn't tend to respond well to standard blood pressure treatment. It can also lead to low potassium levels, which we call hypokalemia. So the new guidelines recommend screening everyone with high blood pressure for primary aldosteronism because it is so common. Something like 14 percent of all individuals with hypertension in primary care setting have primary aldosteronism, which is actually higher in some specialty clinics.

33:17So this is something you've been doing for a few years, I assume, because you got wind of this and you're like, huh, that's interesting. What's the reason why you think this took a few years to come into the new guidelines? Has it been like collecting more data or just because things move slowly in medicine or like, what's up? Yeah, a little bit of all the above. As a kidney physiology nerd, this definitely caught my attention. And yeah, so I first caught wind of this several years back by way of some endocrinologists who I follow and reading some of the papers that they were citing as this being definitely way more common than was recognized.

33:56And I know we have plenty of medical trainees, students, residents in the audience, even obviously colleagues and things like that. And we think back to how we get taught about this condition in medical school, about primary aldosteronism, or also known as Kahn syndrome, where you have this benign adrenal tumor as the classic kind of teaching that is overproducing this hormone that leads to salt retention, blood pressure elevation. condition. The way we are taught about this condition is that you should start to suspect it when somebody meets criteria for what's called resistant hypertension, meaning difficult to treat high blood pressure.

34:33So in other words, somebody comes in with run-of-the-mill high blood pressure, you don't actually think about this until much, much, much later in the process. And the criteria for resistant hypertension is for people to be on maximal doses of at least three drugs and one of them has to be a diuretic drug. And all of that takes a fair amount of time for a patient to get started on one drug and then another drug and a third drug and for the doses to get maximized. Or if they have the textbook features of very, very high blood pressure and low blood potassium levels, which as with most kind of like textbook collections of findings, doesn't actually happen in most patients.

35:13So most patients with this condition don't have that kind of characteristic finding of super high blood pressure and spontaneous low blood potassium levels. And so I think the issue was that too few people were thinking about this condition, and it was not commensurate with how common it is. That was under-recognized. I think if you tell most people that up to 14 % of people with high blood pressure in a primary care clinic might have a degree of this, because just like high blood pressure itself, it's not a binary, You have it, you don't, but it's rather a spectrum. So you don't have to have a blood pressure of 180 over 110 with a super low blood potassium level to have primary hyperaldo.

35:53It's how much are you actually producing and what's the net impact? So you can have it with much milder blood pressure elevations and without low blood potassium levels at all. I think that any of the primary care docs who are listening to this right now, they have well over 100 patients in their primary care patient panel who have high blood pressure just because of how common it is, right? Upwards of, I think, around 45 % to 47 % of adults in the U.S. have high blood pressure. So if you take their primary care panel, you know that over 100 patients in their panel have high blood pressure. 14 of those have some degree of primary hyperaldosteronism.

36:27I would suspect that anywhere from zero to like two of those might even be detected or suspected. And even for those who are on multiple medicines, including a diuretic and things like that, it is often still insufficiently tested. maybe because the person also has obesity or they have sleep apnea and people think, oh, I have better explanations for why they might have this. And so it's not actually tested. So I think that we think about it too late, not often enough that doesn't match the prevalence of this condition in practice. And again, what I keep coming back to is if somebody needs to meet those criteria to be on all these medicines at high doses, that could take a year or longer for somebody to get on all of those things.

37:06And we know that people with primary hyperaldosteronism, even for a similar degree of blood pressure elevation, they have a higher risk of strokes and heart attacks and atrial fibrillation and heart failure and kidney disease. And this is in part thought to be just due to the direct toxic effects of aldosteronism, aldosterone, the hormone in the body, right? And so it's not equivalent to somebody else with the same degree of blood pressure control. We keep coming back to this in different conversations, how you get there matters. So if your blood pressure gets up to a certain level because you're deadlifting short term, not what I'm worried about.

37:42If you have run-of-the-mill high blood pressure and you get up to that level, okay, I'm concerned. If you have primary hyperaldosteronism and you get up to that degree of blood pressure, I'm even more concerned because I know that even for a similar degree of blood pressure, you have a higher risk of having all of these bad complications. And then the other consideration here is that this is a much more straightforwardly treated condition because we have medicines that directly block aldosterone called mineralocorticoid receptor antagonists like spironolactone, aplarenone, etc. and some other ones that can have effects on this pathway.

38:17Or if somebody has that benign tumor in their adrenal gland, they can undergo surgery, cut it out, and then they're cured of all high blood pressure and they don't need to be on any medicines. I've seen this miraculous effect happen in patients who are found to have those benign tumors. You cut it out and they're cured. I think a lot of patients would take that if you find it. But the only way you find it is if you think about it and you look. And that involves doing this straightforward blood test. And so, yeah, ever since I learned about this a few years ago, I said, well, I'm going to start testing this in pretty much everyone I diagnosed with high blood pressure in a primary care setting.

38:49I'm not doing it in my hospitalized patients because that's not the right place to be doing that in general for most patients. Once in a rare while, I'll still do it, but not often. And so sure enough, you know, a couple of years down the line, now we're starting to see it incorporated into more clinical practice guidelines. And so hopefully this gets disseminated both from the guidelines and from us talking about it here today. Yep. One correction, and I'm going to quiz you here on the spot, which I know that you love. Are you aware of the differences between renin and renin. Well, I almost corrected you because I know that nephrologists were going to get triggered that the correct pronunciation is renin.

39:28Yes, exactly. Yes. It's often mispronounced, but I wasn't going to be that annoying. No, no. Yeah. So not only when I was doing my master's in anatomy and physiology, the professor was like, you know, I'm sure either I or another one of my classmates said renin because you just see it. It's common. Yeah. And he goes, renin's in cows. It's a digestive enzyme. It curdles the milk, you know, whatever. And other ruminant animals have it in their gastric juices. Humans, we're talking about renin when it comes to the renin angiotensin aldosterone system. So, look, I forget his name, my professor. But if you happen to be listening to this, I'm so sorry.

40:05You taught me well. I'm just an idiot. So I don't know what to tell you. All right. Well, no, that's a good summary. Definitely practice changing, I would suspect, for many. And yeah, so that's definitely an important part of this update. Speaking of updates, let's talk about some updated treatments here. So traditionally, treating individuals with elevated or high blood pressure meant starting on a single medication at a standard dose and then increasing that dose as needed to achieve the target blood pressure or blood pressure goal. Occasionally adding additional medications as needed. However, new data has been flipping this on its head, which, again, if you're a skeptic, you're like, of course, big pharma is coming out with these new studies where you have to use more medications.

40:52So, Dr. Baraki, why don't you unpack this a little bit? Like why is this becoming a thing and like how does this actually change practice with respect to treating elevated blood pressure? Yeah, this reflects how I've been doing this for a while now and is also a little bit more coherent with a similar approach to how I tend to manage high blood cholesterol levels, at least in patients who are not like ultra, ultra high, high risk. And one caveat here is that treating high blood pressure also first line, including in every clinical practice guideline that you read is going to involve all of the lifestyle modifications that we talked about earlier, all of the things that are in our guide on high blood pressure on the website that relates to things like improving the quality of the dietary pattern, getting sufficient physical activity, addressing obesity, sleep, alcohol, things like that.

41:36So we have detailed information on that for people. So it's not necessarily jumping straight to a blood pressure medicine, unless you do need to jump to that based on the person's risk and that whole conversation that I discussed earlier. And so, yeah, when I went through training, it was typically you just start one med because that's simpler. And then you maximize, get up to the max dose. And then if you still need more, then you can start a second one. And the idea there was to keep things as simple as possible. for patients. We've talked about this a little bit again in the realm of lipid lowering, and I'll readdress it here, but this topic was prompted by a new meta-analysis that I believe was published in The Lancet of almost 500 randomized control trials, so 484 RCTs, over 100 ,000 patients in these trials.

42:17And it was basically looking at what is the treatment effect based on different ways of using these blood pressure medicines. So I'll explain this slowly because it is really important to understand. If I start you on a single medicine at the standard dose of that medicine, on average, I'm going to get about 8.7 millimeters of mercury lowering. So that's, say, for your top number on that blood pressure. On average, across the most common, like, first-line classes of blood pressure-lowering medicines, one drug, standard dose, about 8.7 percent—sorry, 8.7 millimeters of mercury lowering of your blood pressure.

42:54If I double that dose, take you from a standard dose up to twice that much. On average, I'm going to only get an extra 1.5 millimeter or mercury lowering of your blood pressure on top of the initial almost nine from the standard dose. So standard dose about nine, doubling that only about 1.5 points more blood pressure lowering. Now, what goes up as we tend to double, triple, quadruple doses is the incidence of side effects. Now, in general, these blood pressure medicines tend to be quite safe and don't tend to have severe side effects in most patients, even at higher doses. But at higher doses, side effect risks are going to necessarily go up, whereas it seems that the effectiveness that I'm getting out of it is diminishing significantly.

43:40What if I start you on two medicines up front, and both of them are at the standard doses? I'm going to get, per this data, these data, 14.9 millimeters of mercury lowering, so about 15. What if I double both medicines? So now you're taking two medicines at double the standard dose, then I'm only going to get 2.5 points additional. So you see a similar pattern here that that additional lowering is significantly mitigated as we crank up the doses. And again, side effect risks tend to go up. What if instead I put you on three different medicines at a quarter of the standard dose? So on one hand, you're like, oh my gosh, can you believe it?

44:20They're putting me on three drugs. Well, they're on a fraction of the standard dose. So you're getting a whiff of three different medicines. I'm already getting 11 millimeters of mercury on less than standard dosing, meaning that side effect risks are even lower. But I'm getting more effectiveness than one drug at the standard dose. And the reason why is different people's blood pressure can be elevated for different reasons. And when we use different treatment methods, different medicines, different lifestyle things, we're essentially attacking the problem of the ultimate high blood pressure from multiple different angles.

44:54So some people's blood pressure might be driven a little bit more by their obesity than by their alcohol use. If I address their obesity, then that might have a bigger impact. If I get them to lower their alcohol use, it might have a little bit lesser impact. Somebody else might be the opposite pattern. And so by addressing both of those things, I can have the biggest impact on people's blood pressure. This is a similar phenomenon. Some might be due to sodium retention. Some might be due to vascular constriction. Some might be due to other factors. And so using different medicines that work differently can tend to give us bigger bang for our buck such that we can use even lower doses than might be standard.

45:31And we see this most significantly at a quadruple therapy. So So four different drugs, but at a quarter of the dose, tiny, tiny little doses can get on average 22.5 millimeters of mercury lowering, which is substantial, really substantial, right? And by using quarter doses, the risk of side effects is trivial at that level compared with using one drug at double the standard dose or two drugs at double the standard dose where that risk of side effects is necessarily going to be a bit higher. So that's the general pattern. I've had plenty of patients with difficult to control blood pressure who I've had this conversation with And we've ended up opting based on their preferences whether they said I only want to take one pill In which case I might still there are certain combination Single pill products that have two medicines in one pill And so for them the act of taking one pill is actually still delivering two medicines And I might be able to get away with a little bit lower dosing Whereas others say I don't really care.

46:26I'm willing to take as many pills as you want But I want to avoid any side effect possible, in which case I'm willing to give them multiple. And then we go with, you know, ultra low doses and and see a more significant impact that way. Yeah, no, that's a great summary. To me, it kind of get your take on this. All right. So we know like with exercise and its effect on blood pressure that when you look at folks with blood pressure levels greater than 140 millimeters of mercury systolic, that endurance exercise alone on average lowers that blood pressure by about eight millimeters of mercury. And resistance training on its own tends to lower systolic blood pressure by about eight millimeters of mercury.

47:06But when you combine them, it's like 14 millimeters of mercury, which look, it's not purely additive. So there's some overlap, like similar mechanisms, but I hadn't really put too much thought into this before. I wonder if they do attack resting blood pressure via different mechanisms, like maybe resistance training primarily focuses on like the elastin component of your arterial system. And then the cardiorespiratory fitness is more of like a vasoconstriction elsewhere or something or salt balance. I don't know, something. I'm just making stuff up at this point. But yeah, it wouldn't surprise me if there were like different mechanisms by which resting blood pressure was lowered.

47:45But when you combine the two, you get a bigger effect than either in isolation. So kind of a similar thing here, maybe. Yeah, totally. That's how I think about all these different lifestyle interventions. And for anyone who's interested in, you know, that was kind of a detailed explanation. Interestingly, somebody put together a cool website based on this Lancet meta-analysis. They call it the Blood Pressure Treatment Efficacy Calculator. and you just go to bpmodel.org, bpmodel.org, and you just hit start and you can put in some numbers. And based on the data from that meta-analysis, it can essentially predict for you what would be, on average, the expected treatment effect of some combination of these different treatments.

48:24What would be the expected treatment effect of replacing table salt with sodium bromide?

48:32Neuropsychiatric devastation. Just, yeah, bromism. All right, fair enough. All right. OK, so there's also been updates to monitoring specifically with self-monitored blood pressure, so taking blood pressure at home. The purpose of this like self-monitored blood pressure should be to check for, quote, true changes in resting blood pressure that ultimately is used to guide either medication adjustments, the initiation of medications, so on and so forth. So if you frequently monitor your blood pressure at home, you want to make sure that if a change is detected, that it's a significant change. It's real.

49:10It's not an artifact or a hallucination and that it correctly informs decision making. So there's been some update here based on new evidence that's come out. Dr. Baraki, do you want to summarize some of this new data and kind of how this shakes out with respect to clinical practice? Yeah, I came across this paper recently, and it also impacted how I think about this a little bit. And to paint a broader picture here, there are a lot of things that can be tested. We've talked about this a lot before. You can test all sorts of blood tests. You can test physiologic parameters like blood pressure.

49:45You can test blood sugar. And so you can go absolutely wild with this stuff, right? The extreme example would be getting like a full set of blood tests done every day, right? there would be a lot of noise in that data. Your white blood cell count is going up and down hourly throughout the day. Your testosterone level going up in the morning, down into the afternoon, bottoms out in the evening, and up and down again. Your cortisol going up and down. Your other hormones, your creatinine, your BUN, your potassium, all these things are changing all the time. And so the question is, what degree of data frequency do we need to make decisions that actually impact people's risk?

50:23because I think it is tempting, especially for those who are more either just maximizers who wanna do everything, but also people with medical conditions, it can get to be burdensome to be a patient. There is a phenomenon in the world of diabetes called diabetes distress, where you just are overwhelmed with the sheer burden of all the things that you need to do to manage your condition. And I see this a lot. I see patients who maybe, if you're on insulin, that's necessarily a little bit of a higher risk medicine. And so that often needs blood sugar checks to manage it safely. But I also see patients with diabetes who are not on insulin, who are checking their blood sugar all the time and wanting to change all sorts of things that they do based on checking these things.

51:07We've talked about this before. The extreme example being people who don't have diabetes using continuous glucose monitors. And they see the number and they're like, whoa. Yes. And making constant decisions about it. And if, look, if that is your jam, go for it. but it is probably not necessary to achieve the health outcome that we're looking for. And it can lead to a lot of distress or anxiety. It can lead to a lot of unnecessary attention to things that could be better spent, just like going about your life, maybe forming healthier relationships or doing something else with that time. And so there are people for whom I recommend, hey, we should probably check this less.

51:45We don't need to be checking your blood sugar all the time. And the same applies with blood pressure. I think this also is in part because people think that blood pressure delivers its risk on shorter time periods than it really does. So some people think my blood pressure is a little higher today. Am I at higher risk of having a stroke today? And it's a little lower tomorrow or it's higher during this time of the day, lower during this time of the day. And as we've talked about, this is a cumulative lifelong thing. So the risk of high blood pressure that I worry about is high blood pressure that is present over the course of years to decades.

52:19right? It's not that your blood pressure went up this morning and was normal tomorrow morning and was low the day after that. I'll have to interpret that in a broader context because it would be a poor idea for me to be overly reactive and to change what we're doing based on every single data point. I sometimes see patients who are instructed to take their blood pressure and then only take their blood pressure medicine if their blood pressure is above a certain cutoff. And I'm like, that ain't how this works. That is inadvisable for a lot of reasons and generally is a poor idea. So the idea, you know, we've been talking this whole episode so far about how important blood pressure is, how it's the leading modifiable risk factor for heart disease, cardiovascular disease complications and premature death.

53:05And so you might come away from all of our conversations so far. It's like, oh my gosh, I need to be so worried about my blood pressure. I should be checking it every day or multiple times a day. More is better. and it's like, maybe not, right? It is very important as a health-related parameter, but that doesn't mean you need it to be monitored constantly, right? The analog of a continuous glucose monitor would be for you to just be like living your life with an arterial line or a constant blood pressure monitoring device, which we'll get to in a little bit with this Apple Watch, and what the potential upsides and downsides of something like that would be, especially if you are paying such close attention to it that you feel compelled to act on every deviation, right?

53:47So if it goes up a little bit, what do you do? If it goes down a little bit, what do you do? That's not really a way to live life. And so what these data that were published recently ultimately showed us, just to distill a whole lot of detail down, is that a lot of the time, if you're checking stuff really frequently, much of what you are catching is noise. And if you space things out a little bit further, you are less likely to get caught up in all of that noise. And so you want to know what is the optimal kind of retesting interval that you should use in order to reflect a true increase or decrease or stability in your blood pressure.

54:26And so what they found was that at a six-month retesting interval, if somebody's blood pressure was elevated at that time, it only had a 25 % chance of reflecting a true sustained increase in their blood pressure. at 12 months later, an elevated reading had a 65 % probability of reflecting a true sustained blood pressure elevation, meaning that there was a third chance that was essentially a false positive reading. There are a couple different ways that you could take this. The first, and what I want to make clear, is you don't need to be monitoring your blood pressure like every day, right, or even every week.

55:01It might be useful early in the process if we're making a ton of active changes to things, but you should not be living your life constantly measuring all of these parameters. The other thing is that in my approach to this, in my practice, when I'm having somebody do ideally high-quality home blood pressure measurements using a validated device and correct technique, I'm not usually making decisions based on a single reading. What some other data has found that we cited in our guide to high blood pressure is that by doing three days of readings, a.m. and p.m., morning and evening, and averaging those, that's good enough.

55:36And also I'll do that, and then it's going to be a while before I do that again, at which point I might make some modifications to the treatment plan. But we're not doing this every day or multiple times a day indefinitely. And ideally, as you get better control, whether through lifestyle, medicines, both, we can space this out more and more and more, and you can live your life and not have to be paranoid about checking this all the time, which is similar to my approach to other things, be it blood cholesterol levels, be it blood sugar levels, things like that. Yeah. I mean, this is also true of other maybe physiological parameters we see in the training space.

56:08You think about like body weight or like muscular strength. Imagine if like every morning without fail, you step on a scale, which I'm not saying that's a bad thing to do, but like, oh, look, if you weigh above this amount, you don't eat. Yeah. Don't eat. You weigh below this, you get to eat, you know, or a, we're going to take some, some measure of strength every single day. And until it drops below a certain level, that's when you get to train. But if it's above a certain level, you don't need to exercise. You're good to go. It's just that these short-term changes are mostly artifacts of like this normal human variability and like an ebb and flow back and forth.

56:45And so you want to make sure that whatever management decisions you're making, in this case, blood pressure, in other cases, body weight, strength programming, blood cholesterol levels. that you're capturing a real change and one that needs to be acted upon. You can use averages over longer periods of time. So if you do the more frequent measuring, that's okay. But micromanaging it on a day-to-day basis for most of these variables is probably not the move. Is that fair to say? Yeah. I think that, you know, as somebody myself who has never been somebody who's willing to, like, weigh, track, or measure macros in my own life, I do my own like auto regulatory strategy tends to be relatively frequent body weights.

57:28However, I recognize that there is a range of just noise in that number. And I'm not acting differently based on those every single day. But rather, it is there to kind of detect trends and impact things that way. And so if over the course of days to weeks, I was noticing that things were going down and down and down or up and up and up compared with where I want it to be, then over time that would impact kind of behavior on average. But this is not something where it's like, oh, my weight is up 0.5 kilos today. I'm going to adjust my daily intake down by this much or up. And then at the same time, if the number was way different than the day before, then I'm going to say, oh, that's probably a false positive.

58:08Something's wrong with the scale. So it's almost recognizing that there's a range of plausible outcomes day to day of noise. And outside of that, it's more likely fake than it is real. And I'm not really acting or doing anything differently until I see a sustained trend outside of where I want to be that prompts action. And so that would be a similar approach here. Yeah. Quick question, just to see if you got this in the dome. On average, what is the heaviest human body weight in a given week for most individuals? What day? Sunday morning. Yeah, exactly. Sundays and Mondays and at least on On Fridays.

58:47The range is typically on the order of a few pounds or so, about 1 % to 2 % of someone's weight. But this can vary by season, holidays, and more. But, yeah, there's like a general rhythm. And some of that's due to dietary pattern changes. But, yeah, things can change significantly as far as like what the scale is able to pick up. But, yeah, I thought that was interesting. Okay. Okay, let's get into the final and perhaps maybe most impactful update that people might be coming across, might be hearing about. Apple just came out with this new hypertension detection feature for the Apple Watch. Now, as you mentioned earlier, nearly half of adults in the United States have a diagnosis of elevated blood pressure or hypertension.

59:30There's another proportion of individuals who do currently have elevated blood pressure or hypertension who have not yet been diagnosed. And so I don't care to speculate on how many folks are out there, but it's a lot. Yeah. Millions of people. And even those who do have high blood pressure, they might not be adequately managed. So this watch and this tool theoretically could be beneficial if it's accurate, meaning is it actually picking up people with elevated blood pressure or hypertension, not giving you a bunch of false positives? So you reviewed this data. We link to Apple's supplied PDF that has a bunch of their findings.

1:00:08What's your take on how good of a job does the Apple Watch actually do at identifying folks with elevated blood pressure? I would say it's medium. And there's a lot of caveats to this. I'm actually I haven't fully made up my mind on this, but we'll just present the data and maybe we'll come to some degree of consensus here. So, yeah, Apple released a PDF that included their data on this that reported overall sensitivity, meaning, you know, what proportion of people is it correctly, you know, catching with this condition is overall about 41 percent of people, meaning that as a screening tool on its own, not awesome.

1:00:52meaning that it's missing a lot of people. So an ideal screening tool would have very, very high sensitivity. It would be very sensitive to detect those with high blood pressure at the risk of catching a lot of false positives. And so then typically in most, you know, traditional screening practices in medicine, we use an initial high sensitivity tool that catches everyone with it plus a bunch of false positives. And then in the subsequent step of evaluation, we use a test that is much more specific, and that more specific test will then tell us it'll weed out those who are false positives and leave us with the population who truly have the condition.

1:01:30Based on various variables to include the overall prevalence of this condition in the population, as well as how sensitive this test is, and the other parameter of how specific it is, where it correctly rules out those who don't have high blood pressure, we can get a sense of how well this test performs. So I mentioned that overall sensitivity is about 41%. So about 60 out of every 100 people who have high blood pressure are not, sorry, of all comers who are wearing the watch are not being caught. Now, among those who have higher and higher blood pressure, so those with stage two hypertension, that's the highest kind of cutoff, the sensitivity is better, which you would expect to find.

1:02:12So 53, almost 54 % sensitivity in that population. So the higher people's blood pressure gets, the better this test gets at detecting it, which is not terribly surprising. Yeah, but also not great either. You're like, look, this is the highest cohort, the highest blood pressure measurement. You would expect that sensitivity if the detection software or whatever was very, very good. You would expect that number to be in the 90s. It's like if you set the BMI cutoff right now, the cut point we have for obesity is 30, right? And unfortunately, we miss about half of folks who are carrying too much body fat with that cut point.

1:02:46It's just not low enough to capture individuals who are carrying too much body fat but don't have a BMI level high enough. So you would set it to like 22. Well, now the sensitivity is 100 percent. But the amount of false positives that you're getting are substantially increased. It makes for a better, quote, screening tool. But then a bunch of folks are like, what do you say? Do you imagine the internet would actually explode? They're like, you're saying that I'm obese? It's like, well, no, we're just trying to improve the sensitivity of this test, but the specificity would be lower. Yeah. So, I mean, for this test, the sensitivity of it is not – we're missing a bunch of people.

1:03:20But what's the other side of that coin is that what we'll call the specificity, correctly ruling out those who don't have high blood pressure, is much better. And you can see that from Apple's perspective, if they took a lot of, you know, doctor's advice to heart and said, we want to limit false positives to reduce unnecessary worry, which is what they described in their paper, then this is a way to do that if you don't have a quote unquote gold standard test that has really, really good sensitivity and really, really high specificity because those that combination is rare in diagnostic medicine.

1:03:50And so if they opted for something with more specificity, then you're not going to freak as many people out because you're not going to have as many false positives. But that comes at the risk of more false negatives, people who are not caught with this. Ultimately, this trend of wearables is a complex space. The Apple Watches have long had the ability now to detect things like atrial fibrillation. And that's an abnormal heart rhythm that can lead to consequences. but it has left a lot of doctors in a bind with what do I do with this information when an Apple watch tells me that this patient has had atrial fibrillation because all of the evidence that we have on how to treat atrial fibrillation comes from an era when we diagnosed atrial fibrillation differently.

1:04:35And so they're just different populations of people who come in, for example, with symptoms of their heart racing, beating out of their chest with atrial fibrillation. That's a fundamentally different person than somebody who says, oh, my Apple watch told me I had like 15 seconds of AFib and I didn't feel anything, right? So we don't have good evidence on that population of should we manage it the same? Do we not? And so I think similarly, if we're going to have a new tool like this, ideally it is a bit better in terms of its accuracy, but also what do we do with this? And we would have to probably confirm and validate those findings using more traditional blood pressure measurement methods, because that's the evidence base on which our treatment kind of recommendations come from.

1:05:13And so to give people an idea, because we gave a lot of biostatistical numbers, which even makes medical trainees and other physicians' eyes glaze over. Given that about half the population has high blood pressure, to put these numbers into some real-life values, if we put Apple Watches on 100 people, 20 of them will test positive and have high blood pressure. Nine of them will be false positives. 27 people with high blood pressure will be missed. And 44 out of the 100 will be true negatives, meaning they don't have high blood pressure and it will not advise them that they have high blood pressure.

1:05:56So 20 correctly diagnosed with it, 44 correctly diagnosed without it, nine false positives and 27 false negatives. So do with that what you will in terms of deciding, do you like this tool, the Apple Watch for blood pressure detection or not? As a, you know, as a clinician, it's not going to be my favorite thing. And regardless, if I have a patient who tells me that my Apple Watch is telling me that I have high blood pressure, I've never had a high blood pressure measurement before. I've never been told I had hypertension. We're going to go through some additional steps to confirm it. I'm not going to jump to immediate treatment based on Apple Watch data alone.

1:06:27If this ends up getting more people who have high blood pressure and didn't know it diagnosed and treated, then maybe this ends up being a net benefit. But it is insufficient on its own for this. In other words, people should still be, I think, checking their blood pressure on the recommended intervals in other ways in case they're among that 27 out of 100 who might get missed if all they're relying on is just, ah, my watch will tell me if it's a problem. Yeah, I think the best use case I see for this, which is maybe a little interesting from like a social dynamics perspective, is like if you happen to have an Apple Watch, but you for whatever reason don't have a primary care physician, you don't interface with your primary care physician, and it does happen to detect that you have elevated blood pressure.

1:07:11That's probably a net benefit if it triggers a behavior to go see a doctor for an assessment. I don't know that this replaces like regular blood pressure screening, nor should it, but I don't think it's aimed towards that. It's more like if you happen to be between your intervals of like regularly seeing a physician, especially maybe if you're younger and you don't routinely interface with a physician, maybe that's the best use case here. But otherwise, I don't think it replaces either self-monitoring via more validated methods or, you know, in-office measurement with your physician. Does that seem fair?

1:07:46Yeah, I think that's fair. All right. Well, look, I can't say that this is going to be our last blood pressure podcast because that seems unlikely. As stuff continues to change, we'll continue to update you. That's one of the things we like to do here at Barbell Medicine. but we appreciate your attention and listening to our podcast. But before you guys go anywhere, please leave us a five-star rating and a review. It really helps drive traffic to our podcast so we can keep bringing you all the latest nuance in health and fitness. From everyone here at Barbell Medicine, special shout-out to Dr.

1:08:17Austin Baraki for joining us. I'm Dr. Jordan Feigenbaum. We'll catch you next week and every week right here on the Barbell Medicine Podcast.

1:08:31You