19min chapter

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Unlocking the Secrets of Heart Rate Variability with Dr. Andrew Ahn

The Joe Cohen Show

CHAPTER

Understanding Heart Rate Variability and Its Influences

This chapter explores the complexities of heart rate variability (HRV), highlighting the significant role of genetics and lifestyle factors in its measurement and implications for health. It discusses the relations between HRV and conditions such as mortality, as well as the benefits of breathing techniques and wearable technology in enhancing HRV. Finally, the chapter presents polygenic risk scores and a comprehensive list of lifestyle recommendations aimed at improving HRV.

00:00
Speaker 2
I find most of the time, it's not, most of the time people with high HRV's, I feel like it's mostly genetic. Like it's not things that you could people with these high HRV's and it's just something they've always had. That's in my experience and the people with low HRV's, I do think you can change it a fair bit, but you're not going to go from 20 to 100. I've never seen that, right? Yeah. No, I don't see that often. Yeah. It's really hard
Speaker 1
for me to say what are the contributing factors in terms of even the genetics, because the literature, I think is all over the place. It's go down to as low as 15% of your contributing factor to 50 to 60 to 70%. It's one of those things. And also there's, it's so variable. There's so much day to day, even our changes that you get with it. And also age plays a factor. Gender plays a factor as well. As your heart rate variability goes down as you age as well. So it's just, it's really hard to study this in terms of giving a formula and saying, what are the contributing factors? Because it's so dynamic.
Speaker 2
Is the Aura Ring a good way to track HRV? I actually don't know much
Speaker 1
about the Aura Rings calculation. So as you probably know, a lot of these wearable devices have their own proprietary formula, and I don't know exactly what goes into their calculations. Like Aura, I presume it's just like most of the other devices they're using RMS-SD. The good thing with these ring watches is that because of the location on the finger, you tend to have more like the capillaries are the density of the capillaries are higher in the fingers, particularly on the palm part of your, like the front of your fingers. And that, that you'll probably get a cleaner PPG signal, like a, then you would on a wristwatch. But that's the only thing I could say about, about that. So when I'm talking about into RMSSD, I don't know, like for instance, Morpheus, I don't know. I don't actually use Morpheus, but I think what they do is they take a log transform of RMSSD and then the apply a multiplier so that there's a standard of like up to a hundred or something like that, or it may have their own formula as well. So it's, it's hard for me to, and I don't use an or ring, so I don't know exactly what they use. Yeah.
Speaker 2
Based on what I've heard, it seems like it's pretty good, but I, and I do see a lot of people with the aura that have 20 and 15 even. So it's not like 90 is just less. But I will see people with the aura who have 150. It's very rare, but does that mean that these people are even healthier or there's a certain cutoff by which if you go higher, it's not better. So one of the things that can contribute to high heart rate variability is if you actually have
Speaker 1
a condition that has a neurotic heart rate, if you have atrial fibrillation, for instance, then your heart rate variability, your RMSSD could go pretty high and that may actually be an indication of bad, a state of things rather than healthy of things. So if it's really high, then you have to ask the question whether it's, if it's actually an indication of good health or not. Because the heart rate variability is only useful if you're actually tracking the normal sinus rhythm. Like the SA node, the sinus atrial node is a pacemaker, I should say, of the heart. And it gets input from both the parasympathetic and the sympathetic nervous system. And so when you are studying your heart rate and heart rate variability, you're assuming that it's the SA node that's driving the heart in terms of the beats, to be edgables. However, if you have ectopic sites, if you have areas in your atrium or even in the ventricle, that's like occasionally putting out signals and then running the heart in terms of the heart rate, then it could cause some elevated heart rhythm, like HRD. And that's not necessarily healthy.
Speaker 2
Got it. So it could be the outliers. There's some problems there. It's not necessarily healthy. Yeah, exactly. And what do we see in terms of overall all-cause mortality for HRV? What numbers would we see as the lowest all-cause mortality? A lot of these studies were done in
Speaker 1
the 1980s when they actually assessed. That was at a time when Holter technology, which is a way to record, was just good enough so that a person could potentially measure it and send it home. But a lot of these studies were actually done at spot intervals. Basically, the patient would come in at a particular time of day. They try to control the variables, make sure you're fasting, you're not drinking coffee, you're relatively well-hydrated, you're in a seated or supine position. They try to keep it conditioned to control, but it was a spot assessment. So a person would come in for one day and they use that data then to then figure out if that's a prediction for all-cause mortality or cardiovascular mortality in the long run. And I don't know the exact values, but clearly at that time, lower heart rate variability was associated with higher all-cause mortality and cardiovascular mortality. And I think the heart rate variability, a lot of what, what they use was SDNN, standard deviation of N intervals. So N actually means a normal rhythm as opposed to RR is just any type of heartbeat. It doesn't matter if it comes from the SA node or even if it's an act topic beat. So the SDNN makes sure that you're dealing with a normal sinus rhythm, which is what sort of gives you information about the balance between the sympathetic and parasympathetic system. And so what they did at that time was they use SDNN and then looked like one day or even one morning, and then they followed up a year or two years after and saw that, yeah, there was a correlation, which is amazing to me, given that since there's so much variability from day to day,
Speaker 2
that one spot assessment could actually predict for mortality. Interesting. And besides certain things that I know are very significant for my HRV, like alcohol, sleep, stress, how much I exercise and how much I activate my nervous system as in general, I think. So if I like, even if it's not exercise, if I like go to the sauna, do a cold plunge, exercise, and just super active in the day, my HRV is going to go down just because it's too much. That's the only things that were like super clear to me. Then there's things that kind of help a little bit, but it's hard to say long-term. It's not so drastic like alcohol. You drink, I drink alcohol. It goes down like 20 points. Yeah. Yeah. It's just very clear. It's very clear. It's super clear. Yeah. Yeah. It's amazing.
Speaker 1
And for me, probably it's worth it just because I've got that Asian flesh occasionally. So like very built, it goes down significantly. I don't respond well to alcohol. Yeah. Exactly.
Speaker 2
So besides those things, general stress reduction, things like that, what else is capable of moving heart rate variability quite significantly? Yeah.
Speaker 1
Sleep is important. Your state of mind, obviously, if you're stressed, that's really important. When I get sick with an upper respiratory infection, it's dramatic how much my heart reverberability goes down and it actually does a pretty good job of telling me when my body is close to recovery. Like just a month or two ago, I had a upper respiratory infection, probably viral, that lasted about a few weeks, but in the middle of the third or fourth day, I was like, okay, I think I'm going to recover. But Mark Hartweiler variability was not showing that. It was showing that it was continuously at a decreased level. And then, and then I said, okay, maybe I need to rest a little bit more. And then, so it does a pretty good job of even predicting before consciously, I'm aware of the fact that I'm getting better or even getting sick. It's a harbinger of things. So I think that's, that's where it's really been helpful. So viral things. The other thing that seems to help, I don't know if you've heard of heart rate variability biofeedback. General. Yeah. It's kind of feedback. Um, what you want to do is, so as it turns out a lot of the heart rate variability that you see on these devices, it's reflecting what's called the respiratory sinus arrhythmia. So as you breathe in, your heart rate goes up as you breathe out, like your heart rate goes down and what it is that your parasympathetic system is either being turned off or on with each breath. If you take a breath in, the parasympathetic is inhibited. And then as you breathe out, the parasympathetic sort of re-enacts and acts to lower your heart rate. that is what a lot of the heart rate variability is measuring. So it's a marker of your parasympathetic nervous system. And what they found out also is that in order to maximize that respiratory sinus arrhythmia, the changes in heart rate with each breath, the, it changes with your rate of respiration as well. So if you breathe really slowly and probably a breath every 10 seconds, then you reach what's called this resonance, resonance frequency. Basically you're breathing your heart rate and your blood pressure, all sort of act in synchronization. And as a result of that, your heart rate or your heart rate gets maximized at every 10, when you breathe every 10 seconds. And when you do that, consistently, you're almost training your body to operate in a way so that your bare reflex, bare reflex is that is that blood pressure sensor to determine what your blood pressure is. It's much more sensitive or becomes more sensitive. And so what you can do if you do this exercise is that over time your heart rate variability can increase. I think I use a device like that actually
Speaker 2
from,
Speaker 1
I forgot what it was called, from the HeartMath
Speaker 2
Institute. Yes,
Speaker 1
yes.
Speaker 2
Yeah. Do you want to take a deeper in-breath and then slowly breathe out? Is that what the idea is? So that extends the time of your breathing?
Speaker 1
Yeah, actually, according to their model for HeartMath, I think it really didn't matter. I think it just maybe five breaths in, five breaths out. There are different types of breathing that's out there. There's a box breathing, you take a breath in, you hold it, and then you breathe out and then hold it. But it depends on who you ask. Some believe that if you prolong your aspiration or escalation, you're activating the parasympathetic longer, but I'm not really sure whether there's actually a difference in terms of outcome measures. Yeah. And that's one of the things I'd be really interested in seeing, you know, what the data shows. Okay, so what is the most study
Speaker 2
type of breathing that improves heart rate variability? Oh, it's a very simple in and out. Take a
Speaker 1
breath in. And then ideally, you want to breathe through your nose in and then usually you ideally want to do diaphragmatic breathing so you're not using a lot of your external costal muscles you're not using your rib muscles you're actually trying to use the diaphragm primarily so when you're breathing in. So if you didn't
Speaker 2
both speak it would be like breathing in from the stomach.
Speaker 1
Yeah what happens is that is your diaphragm comes down when you breathe in and you're primarily depending on the diaphragm, your abdomen starts to come out. So yeah. So you take a deep breath in, but you do it slowly through the nose for about five seconds, using mostly diaphragm and then out and
Speaker 2
for five seconds. So that's pretty simple breath. Breathe in for five seconds, breathe out for five seconds. Yeah. My question is if you're, when you're breathing out, you touched on this before. You increase your heart rate variability, your parasympathetic nervous system. Why wouldn't it be that, yeah, why wouldn't it be that you want to breathe in as quickly as possible?
Speaker 1
And then breathe out slowly. Yeah, I think that's a feasible option. It's one of those things that, you know, you want to assess your heart rate and heart rate variability and see how that affects you in the long run. I think the one that clearly affects because the, what's contributing to our heart rate variability is obviously not the parasympathetic, it's the parasympathetic sympathetic, more the parasympathetic when you're talking about the shorter time frequency heart rate variability. But it's also the baroreflex, it's the pressure sensor and in your crowded artery. And so what it is that you want to give it a time for it to train itself to response to changes in the blood pressure. So if you take a dramatic inhale like that, I don't know the, like the, what that effect will have on the blood pressure or how quickly the bare reflex will respond to that. So I don't know. That's one of the things, that's why we created, we created Labrun, is just to be able to actually get that data. You're just using a wearable device and do different types of breathing exercise and see how that sort of changes your heart rate variability in the long run, short term and long run.
Speaker 2
Okay. Is there anything else that noticeably increases heart rate variability that we didn't discuss? There
Speaker 1
are some things,
Speaker 2
there's some belief
Speaker 1
that if you're exposing yourself to certain hypoxic environments, like I think they've done this in some of the special forces where you're almost like stressing your body for a little bit, forcing it to adapt that then after a while your body is then increases heart rate variability. There seems to be a nice medium. Obviously, if you are just living a stress-free life, purely a stress-free life, then your heart rate variability will be good, but it's not going to increase necessarily. Your heart rate variability may be a marker of your ability to adapt. If you expose yourself to stressful conditions, then maybe that's why a cold plunge is useful. or being in hypoxic environments or doing something that actually temporarily forces your system to go to certain extremes, then I think that enables your body to be trained to be adaptive and your heart rate variability is a reflection of that. So
Speaker 2
that would be similar to Wim Hof breathing. Let's say the box breathing you breathe in, breathe out. And that creates a type of hypoxic environment in the short term. Like, yeah. That box breathing? No,
Speaker 1
I think that's different. Okay. Yeah.
Speaker 2
I'm not sure what box breathing is, but I just. Box breathing, I think as you breathe in and then
Speaker 1
if you can imagine your, your inhalation, inhaling, you hold it and then you're exhaling, you hold it. So it almost looks like a box. I don't know. That's my opinion. I'm not, I'm not breathing expert. So that's the thing there. There are probably so many other types of, there's something called bhudjai breathing in yoga, where you're trying to create the sound and the trachea. That also apparently has some benefits. I'm not an expert in this and I would love to learn more.
Speaker 2
Yeah, interesting. So yeah, I think one of the things you mentioned is also quite important that I've noticed as well as the infections, inflammation, chronic inflammation from any cause really, it's either toxin, just anything, right? Usually it's going to be an infection, but I've also found that dramatically. He could cut it in half pretty much.
Speaker 1
Oh, easily. Yeah.
Speaker 2
Yeah. Yeah. So I'm looking at my genetic report on self-decode just to see what my predisposition for heart rate variability is. It says I'm predisposed to a higher HRV. Oh, no way. Yeah. And let's see, it's looking at 1,286 genetic variants. So it's a polygenic risk score. And it says here, based on the studies, we found up to 60% of differences in people's HRV may be due to genetics. So it does seem to be quite heavily genetic.
Speaker 1
Yeah, I'm curious to see what are the components in your genetic study is contributing to H. Herbie? When you say
Speaker 2
components, what do
Speaker 1
you mean? Are you assessing SNPs or what exactly are... yeah. And I'm just curious, what are the... what genetic expression? Is it a specific receptor? Is it...
Speaker 2
what is it? Oh, these polygenic risk scores, they look at many variants, the ones, the advanced ones that we have, they look at many variants. So there's no specific one, but there are specific genetic variants that we have here that you could see there's a bunch of them that relate to HRV. But in general, when you're looking at many genetic variants, it like just looks at the whole picture together, right? It's hard to isolate a single genetic variant, but we do have certain genetic variants that you can look at that play a role. Those are on the report. And you could see, for me specifically, which ones lower it and whatnot, but that's more of an advanced feature. And then I see we have 52 recommendations. I'm curious what you think of them. Yeah. So let's see. So these are the lifestyle ones. Strength training, avoid air pollution, biofeedback, mindfulness, nerve stimulation, alternate nostril breathing, yoga, nidra, diaphragmatic breathing, bikram yoga, deep breathing, cold water immersion, hot yoga, and we could click on any of these to see the references by the way. Yeah.
Speaker 1
How do you get these things that you use pouring through literature or just to see how you get the results
Speaker 2
and that? Yeah, we could click on any of these. Let's say air pollution. It says air pollution may decrease HRV by altering the activity of autonomic nervous system. The longer the exposure, the more HRV may decrease. Studied air pollutants include particulate matter, ozone, polycyclic, aromatic, carbon monoxide, carbon disulfide, diesel exhaust. And these are the references. So if we just click on like a random reference, this is a systematic review and a net meta analysis. Yeah. Our study indicates that short-term exposure to ambient pollution is associated with decreased HRV, predominantly as an immediate response within hours. It's, we've got all the research here and in my case, I actually have a genetic variant that exposure to air pollution may decrease HRV more in people with my interleukin 6 gene variant. So this is why the recommendation comes up higher. Wow, this is
Speaker 1
pretty impressive.

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