#79 - The Science of HRV: Advanced Analysis for Healthcare Providers, Part 1

Hi guys. Welcome to another episode of The Factor Podcast. I'm your host, Jessica Riddle. Welcome and thanks for listening. Today we kick off a new 2-part training on harnessing the science of heart rate variability, or HRV, for enhanced patient care with Dr. David Hopper. When it comes to the science of studying heart rate variability, it's more than just a data point or a health marker. HRV is a comprehensive gauge of our nervous system's flexibility and our overall physiological resilience. In this fascinating 2-episode series, our guest instructor, Dr. David Hopper, will share the significance of understanding both the sympathetic and parasympathetic nervous systems for achieving optimal bodily functions, and discuss the potential of HRV in predicting illnesses, and enhancing patient care. We will also explore how this powerful tool helps athletes adjust training schedules and assists medical practitioners in planning better patient care strategies, all while steering through day-to-day physiological shifts. Whether you're a healthcare professional or someone interested in wellness and body metrics, this episode is packed with valuable insights on using HRV to its full potential, so be sure to hit that download button and grab something to take note with. Let's dive in.

All right. Well, thank you so much for having me today, Jessica. I'm very excited to be talking to all of you about my absolute favorite topic, which is heart rate variability. So let's get in here. And first things first, I want to introduce myself. So I am a practicing chiropractor as well as an oral myofunctional therapist. So for those of you who aren't familiar with the second term there, think somebody who does rehabilitation for the airway, mouth, and face. That's kind of my zone. I do a lot with sleep apnea, TMJ, and all of that as well in practice. As well, I'm a father of 2. Those are my children right there, Jovan and Petunia, and my beautiful wife there, Brooke. And we are located outside of Chicagoland here in We have a few clinics doing different things out here. So chiropractic, then we have occupational therapy, physical therapy, speech therapy, and then of course OMT as well. And I am a, as well, an instructor at the National University of Health Sciences. So I'm in their doctorate program, help— helping to bring chiropractors and naturopathic doctors out into the field. So lots of fun that we get to have over there. And then basically anything heart rate variability certification-wise that you can possibly have or get, I've gone through as much as I could. And I get to talk about HRV everywhere I go too, which is real fun. So that is me. And one more thing that I would like to mention as well, I am associated, my passion for HRV has driven me to, to start an app. So I am part owner of an app within HRV as well. We do have a device as well. So I just want to be forward with my disclosures on that, that I am involved financially with an application as well for this. What were the basics of heart rate variability? So by no means by the end of this course will you be in a place where you can turn around and start using HRV very confidently in practice. For that, I want you to go through our extended, which we will have up here in the next coming weeks here. And, but what we will learn today is the basics. So that way you will know the path to using HRV in practice. And at least what you will have when you leave here today is a good enough understanding to start experimenting on your own and know what you are looking at. So again, just a general overview here, but the first thing that we're going to dive into is the history and the power behind heart rate variability. As well, we're going to define heart rate variability. So with heart rate variability, this is not a new science, although it is a hot topic right now. That is just because As of right now, technology is getting to the point where now it is an easy-to-find thing. So, it's an easy metric that we can measure all of a sudden, whereas before it wasn't the case. So, it was actually 1895 was when ECGs first came out and hit the world and we could actually see that variance. Prior to that, we knew that there was a variance in your heart rate, but then we saw that in 1895. Now, in 1930s, they came out with this thing called PPG or photoplethysmography. And that is actually the most commonly used way to detect heart rate from any source. So anybody who's wearing an Apple Watch, Whoop band, Oura Ring, anything like that, that light sensor is a PPG sensor is what it's called. And that's the preferred method of collection nowadays without a doubt. The chest strap monitor that Polar came out with in the 1970s, that was another excellent way for collecting this kind of data. I'm sure you all are familiar with that one. And then in the 1990s, we started to get these wearable heart rate trackers. And this was a huge step forward, a huge leap forward. But then it wasn't until just recently again that we started to have wearables that were able to precise enough that we could actually pick up the R-to-R intervals. And we're going to see what that means, but essentially they were capable of transmitting HRV data. So again, by no means a new topic, right? We have over 30,000 articles at this point. I'm sure this is an old slide, so I'm sure there's over 30,000 at this point published articles on HRV. And that is literally Google HRV and anything. Look up HRV and connect it to any disease process, anything like that. And it's there. HRV is very well tied to everything. It's a A marker for all-cause mortality, as we will see. And just in the past 8 years, this technology has caught up where we can really start using this powerful metric here. This is my guy right here. This is how I feel every day when I talk about HRV. I'm just so excited about it because it's such a powerful thing and it advances us all so much in our understanding of human physiology. And now that it is so accessible, we can use this so greatly with our patients. What is heart rate variability? So for starters, it's not heart rate. And that's the biggest thing that we have to get across because that's my biggest challenge, my biggest hurdle when I talk to people is I say, oh, you know HRV, heart rate variability? And people say, yes, yes. And then about 10 minutes into the conversation, I realized that they were leaving that V off the end and they assumed I was talking about heart rate. So when we put that V on, it changes what we are talking about. So they are not the same thing. When we add that in, right, heart rate is talking about just beats per minute or BPM, and then we add in that variability. Now we're talking about something that is able to adapt or vary, right? So we can change with our environment. So heart rate variability is a heart rate that changes, right? Or we can give it a proper definition, and heart rate variability is the variation of time intervals between successive heartbeats measured over a given period of time. So what exactly does that mean? If we have a heartbeat of 60 beats per minute, most people would assume that your heart rate is beat 1 second, 1 beat, 2 seconds, 2 beats, 3 seconds, 3 beats, and so on and so forth. And actually, that is not at all how it happens, and we don't want it to ever be like that. That would actually give you an HRV of 0. Which would be a very bad place. How it works is more like this picture right here. We have a heartbeat, and that's what this graph is showing. And these are called QRS complexes for those of you who might not be familiar. And a QRS complex is this peak, and we can call this the R spike right there. Between this R spike and this R spike would be our R-R interval. And we want to measure that time distance right there. And as it shows here, This first interval might be 850 milliseconds and the next one 980 milliseconds and then down to 740 milliseconds. And that variation of time intervals is what we are talking about when we say HRV. So, it is that change in time between each heartbeat. And that is very healthy. That is what we want to have. So, in fact, a higher variation is better than a lower variation.

Okay.

When we talk about our HRV, what is being measured? Those are our intervals, and this is our HRV. Now, we are talking, we are talking about not just a simple number here, but what this number is a measure of is our autonomic nervous system. So that is why it is so powerful. The system of our body that runs and governs everything that goes on in the background, which is majority of what is happening with our body in any given moment. We have a measure of this, a very easily accessible measure of this with HRV. So we're looking at autonomic nervous system regulation, or in other words, our ability to adapt to any given thing in our environment. But why should you care about it? Well, low HRV is associated with all-cause mortality. Back to that, right? If we, if we look at HRV and pair it with anything We will see that as HRV goes down, your chances of dying from anything goes up. And it's associated with 9 of the top 10 killers. You can look at this list here of the top 10 killers in the United States, and low HRV is associated with 9 of the top 10. The only one that it isn't directly correlated with is motor vehicle accidents or unintentional death or injury. And I argue that, and the reason why I argue that is because a low HRV means that your reaction time is actually lower. If you are driving down the street and somebody pulls out in front of you and your HRV is higher, and therefore you have a higher reaction time, might you be able to pull the steering wheel out of the way at the last minute and avoid that life-altering car accident, right? Might you be able to change the way that you step off the curb And rather than injuring or rolling your ankle, you actually just walk away and stumble. So we know that HRV may actually be associated with 10 of the 10 top 10 killers. So that's my argument for it.

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What is this again? Autonomic nervous system adaptability as seen in HRV will help us determine a patient's ability to heal and recover. So, when we get a patient in clinic talking to— I didn't get to see all the different healthcare practitioners that are on here, but it looks like chiropractors. So, when we get a patient in clinic and we have a good idea of where their autonomic nervous system is because we are looking at their HRV, then We can determine their ability to heal or recover from whatever it is that brought them in our door. So somebody with a higher HRV is going to heal faster from whatever they walk in the door with. We know that they are going to have a better response, whereas somebody with a lower HRV is going to have is going to have a slower or delayed response. So that can help us with our care planning, and that somebody with a lower HRV is. Probably going to need a longer care plan versus somebody with a higher HRV who we can expect might recover quicker and not need as long of a care plan. And then as well, when we are going through whatever care plan it is, if we see somebody's HRV going down throughout our care plan, then that gives us time to reflect on our care plan and say, are we challenging this person too much possibly? And maybe do we want to back off with what we're doing or maybe talk to them about some of their other lifestyle factors that might be playing in and overwhelming this person's nervous system. And the opposite might also be true, right? That we can confirm that our care plan is going very well and that we are doing the right thing, and that this person's HRV is continuing to climb as they come out of pain, as they continue to improve their life. So HRV has a powerful predictive ability as well. HRV can actually predict the onset of illness. Or injury up to 2 days prior to the onset of symptoms. And that sounds pretty crazy, but when we think about it, it's not all that crazy, right? Because our autonomic nervous system is going to be dealing with some of these things before it ever comes to our conscious awareness, okay? Or before we start to experience symptoms. So this is true with illness. This is true with overuse injuries. Obviously, if you fall off your bicycle, HRV probably couldn't predict injury. So much. But, this is where we're talking about with illness, overuse, injuries. And then, it can also predict performance. And, we're not talking just about physical performance but mental and emotional performance as well. If HRV is a measure of how well our body is dealing with all of life stressors, then we can assume that, and this is also fact, is that somebody who has a higher HRV is going to perform better mentally, They're going to perform better emotionally, meaning that they can have more on their plate before they start to break down. And then of course physical as well. And we see this in the physical in sports, and that's where HRV has become very popular, is that we see athletes training based on their HRV with the best training programs out there. We see that they are, they are reacting and adjusting their training program based on their heart rate variability, and they are having unbelievable outcomes, which is so cool to see. All right, and the one of the more powerful things that we get out of HRV, even more so than that predictive factor, is the deeper insights and the deeper connections that we get with our patients. So when a patient comes in and we see that their HRV is trending in the wrong direction and we're pretty confident that we are doing everything correctly, it gives us that opportunity to talk to our patients to the next level. It opens the door to that conversation where we can say, hey, Hey, Mary, what is going on that we are seeing this trend down? We are doing everything right here in the office. So what's going on at home? Is there something else outside of here that isn't going the way that we want? And then we can start to talk about nutrition. We can start to talk about sleep. We can start to talk about their relationships at another level. And then of course we can make a referral if that's what's going to be necessary, or we can help them with some of those other Adjustments outside of what we are already working on. So it really helps us make that deeper connection with our patients, which I think is just amazing. And the increased self-responsibility too, because patients will deny all day long that having a couple of drinks at the end of the day is really affecting their health, right? But then when you see an objective number staring you in the face saying that, yeah, in fact, when you do that, Your body performs much worse the next day. And same with skipping sleep, right? Well, I'm fine. I don't need to sleep 7 hours. I don't need to sleep 8 hours a night. Well, let's look at what your HRV looks like when you do versus when you don't. And then there is no argument anymore. That is an objective number that tells you both that yes, you actually perform better when you have slept properly. What about the science? Of heart rate variability. So, we're going to jump into this very quick. And again, we are going to skim the surface of this. But, what is HRV looking at? I've said several times what we would define as homeostasis. And, that is the maintenance of a constant internal environment despite our ever-changing internal and external environments that we have around us. Okay. So, we need to maintain that homeostasis. And, how we do that, the work that we put in to maintain homeostasis, Well, we label that allostasis. Okay. Those are our allostatic processes. And then we have the concept of your allostatic load. And how I like to think of this is, is like your load of bricks. So at any given time, ground is our load of bricks. We have these basic things that we're carrying around. And then when somebody hands us something extra, so that weighs us down a little bit. And then we get something extra piled on, right? Call it finances, call it work, call it family stress, whatever it is. it pushes us down a little bit more, right? So we have this weight coming on us, and you can call these stressors, but I hate the word stressors, so I like to call them life metrics because it makes a lot more sense to me. We have all of these bricks, and this is our allostatic load, right? And this is what's weighing us down. So you can imagine that somebody with a very large load of bricks, if they're walking down the sidewalk, it's gonna be difficult for them to move from side to side. It's going to be difficult for them to react to something in their environment. Let's look at the exact opposite. Somebody's just walking down the street and they just have their one little brick and they're walking along all jolly, right? And somebody comes up and asks them a difficult mental question. They can think about that pretty easily and they can be very agile mentally. And if something emotionally taxing happened, right, they would probably deal with it in a very positive way. And same with that soccer ball comes kicking back out again. Maybe that person could stop it, right? Smile, wave to whoever it was, kick it back, maybe even play a little bit of soccer, right? And then get back to walking down the street. And it's the same thing with our allostatic load that we are talking about with HRV. The more that we have on our plate, the more it's weighing us down, the less adaptable we are to everything in life. And that is what our HRV is reflecting for us is that allostatic load or how many stressors we have. Or how adaptable we are to everything in life. Here it is, HRV. This is what allows the body to be adaptable and maintain homeostasis in the face of our ever-changing environments. Okay, so we thrive with high adaptability or high HRV. So that's what we are always aiming for. All right, so what is being measured? Well, I already clued into this. And talking about the autonomic nervous system, that is what we're looking at, is the function of our autonomic nervous system. And as a quick refresher for those of you who may have been out of school for quite some time, we have our 2 main sides of the autonomic nervous system, right? We're gonna, we're gonna ignore the enteric nervous system for the time being. But of our sympathetic nervous system, right? And we can think about that as our gas pedal or our fight-flight-freeze response. And this one often gets a bad rap. And I know for sure as chiropractors, we often talk about this in a negative way and it's a lot of negative rap in other realms as well. And it's not all bad, right? Because if it wasn't for our sympathetic nervous system, we wouldn't get up in the morning. We wouldn't move or do anything, right? We'd never go to the gym. And granted, if we got ourselves to the gym, it's our sympathetic nervous system that makes us exercise, that actually gets us moving and doing these wonderful things for our body, right? It gets a negative rap when it is left on too long. And that's exactly it, is that in the long term, our sympathetic nervous system left on for a long time becomes problematic. That's when we start to see a decreased immune function. We see decreased mental, physical, emotional, all of that starts to ramp down when this gas pedal is left on too long. And you can just imagine, all right, if you were stepping on the gas pedal in your car, And you were just sitting there revving your gas pedal for hours on end, something's gonna break. And it's no different with your body, right? Eventually something ends up breaking, and that's what we see, right? Our sympathetic nervous system was not meant for that. It's meant for acute, quick processes. Let's take care of this and then let's go back to rest and recovery. Okay, so that's, that's what our sympathetics were meant for.

Okay.

So then we have our parasympathetics, the opposite side, or our brake pedal. So this is our rest, digest, relax, recover. That's the opposite side. And this one, although we always talk about this side so highly, it's not all good either, right? We need that perfect balance of the two. That's what we are always aiming for. We need great function of both sides of the nervous system. If this were only parasympathetic function, yeah, we'd have a huge lack of motivation. We'd have poor circulation, right? We'd never do anything in life. And this picture is a great one. This is actually my son and he was really sick. So his body was in full recovery, right? Brake pedal. And then he needed to go to the bathroom. So another big brake pedal action. And he was so parasympathetic that he actually fell asleep on the toilet. I like to say he crapped out on the crapper. And this is a pretty fun way to find him. Makes me giggle. Anyway, so this is our long-term survival strategies is our parasympathetic nervous system. So these are the things that, yes, they do take longer amounts of time and it does take a lot of energy for this side. So we see things like our digestion, our absorption, our excretion of all the— that parasympathetic side, a major part of our immune function, our sleep repair, recovery processes. All of that stuff is happening over here. Oh, and we have a higher heart rate variability when we have a well-functioning parasympathetic nervous system. That does go hand in hand. All right, and we can't talk about our parasympathetics without talking about our vagus nerve. Our vagus nerve is our 10th cranial nerve, and it got its name vagus because it is the vagabond or the wandering nerve. And it does, it wanders from our brainstem, so way up in our skull, And it makes its way all the way down into our abdomen, making a true brain-gut connection. And it does parasympathetic nervous system innervation to all of the major organs along the way down. That is over 80% of our parasympathetic nervous system's function is just in this one nerve, just in this vagus nerve. And another really interesting thing is that over 80% of that information from our vagus nerve is afferent information. So afferent information is that information coming back towards our central nervous system. Okay, and the reason why this is significant is because that means that our parasympathetic nerve system can be stimulated. And if we think about anatomically where that nerve feeds, we can easily influence this nerve. And, we can stimulate our parasympathetic nervous system and in turn raise our HRV and in turn make our ability to handle everything in life that much better. Vagal tone is actually what we are measuring with HRV. And, that's specifically when we see what most things would measure HRV in is that RMSSD, and we're going to get there in 1 second. But, that is a very strong measure of vagal tone. Or the strength or activity level of your vagus nerve. That is very much what we are looking at. Moving on, we're going to get on to how to measure HRV. So, the actual process of measuring HRV. So, anybody on this call who wants to measure their heart rate variability can follow these steps to successfully start measuring HRV. First things first, you need to download your app. So, you can go to the App Store on Apple or whatever you Android people call it. I'm not sure, but I'm sure it has a weird name like Android. So then you need to get yourself a device, and then once you have both of those things, you can connect your device to your app and you can actually start taking HRV measurements. Okay, and how we would do that— we have many apps on the marketplace, so this, this is some of the better apps out there that you could find. And thank you, Jessica. Yes, the Google Play Store on Android, that's, that's what it's called.

Called.

I could not recall it, but it wasn't Apple, so I wasn't very concerned. But these apps right here are some of the better ones out there at the moment for measuring HRV. So I would highly recommend using any of those, starting off with any of those. These are some of the devices that you can use, and the best thing to do is get an open-source Bluetooth device, meaning a device that is capable of connecting to any app, so that way you can try several different apps and you can decide which one you like the best. Things to be cautious of when you get these types of devices is things like your Apple Watch, things like an Oura Ring, a Whoop strap, those are closed. So, that means that even though you can get a reading from those and get an HRV reading from those, we can't really understand what that information was without some higher level of software that can do investigation essentially into those readings. So, I know the Oura Ring has an Oura Cloud where you can see some more of that information, it can be challenging to get that information out to your provider. So especially for those of you on this call who are providers, it's tough to get that information from your patients. Apple measures on their Apple Watch. Their measurements are done in a, in a very different way than anybody else does their measurements. And they throw in a lot of random measurements, measurements, which makes it quite confusing. So I encourage people to go away from the Apple Watch. If they're looking to do HRV readings and use it for anything with their patients or even just for themselves. The Polar straps are excellent. The Polar H9 and H10 are excellent straps, and those are very accurate, easy-to-use readers. So, anything like that works. We have our device as well, the Optimal device, and then there's a couple others out there on the market. What are we looking at? So, when you want to actually go and take your heart rate variability measurement, You want this to happen first thing in the morning. So an overnight reading, as we're kind of finding out here, the overnight readings aren't as good as the morning readings. We, we want to see everybody taking their readings first thing in the morning. And when we say first thing in the morning, we mean literally first thing in the morning. Use your restroom if you need to, but otherwise it's rolling out of bed. You're going to sit up and preferably take this reading in a seated position. And you're going to open up your app. You're going to connect your reader, and you're going to sit there and you're going to take— most apps are a 3 or 5 minute reading first thing in the morning, and then that's it. That's all you need, just that one simple reading. And we want you to breathe at a natural pace throughout that. We want you to keep your mind on neutral thoughts. We don't want you to interact with other people. We definitely don't want you talking because that changes your breath pace, and ideally not interacting with pets or anything like that either. And definitely not checking social media or emails during or before your reading, because as we know, that is very capable of sending our nervous systems into a spiral. All right. So we want to see where your resting physiology is first thing in the morning. And that, when taken over time consistently, can give us great insights into the direction that this person's health is going. Now we want to move into interpretation of HRV. We understand the science a little bit, right? And we understand how to take a measurement. Now, how are we going to actually interpret our heart rate variability reading? We can say higher is better, and that's a very basic way of looking at it, but that's only true most of the time. So really, if we look at this and we just say consistent is better, that might be the best way of looking at it. What we are going to do—you can't diagnose anything with heart rate variability, so you can't look at somebody's HRV and say you're having a heart attack, right? Or you're going to get diabetes. We can't say that. It's definitely not for diagnosing anything, but it's a marker for health. So we can use it as a great indication of which direction somebody's health is going. And as we said, it's a very good as a predictive metric. We can look at that and see that somebody's health is drastically changing and they may be getting sick or they may be setting themselves up for injury. Then we need to mix in these subjective data along with that, and then we can make a very good call as to what may be happening with this person. Okay, so not for diagnosis, but it is a monitoring tool and a very accurate monitoring tool. What we are looking for is a rolling average. So I'll talk to you about quickly. So we want to establish a rolling average on our heart rate variability, and that is going to help us with our interpretation. So over 4 to 7 days, we're going to get a good idea of where somebody's nervous system is sitting at, and we want them to maintain about that same number. If they go up a little bit, that is great, and especially if they go up and they maintain that up, that is even better. That means that we made a very positive change for this person. And that they were able to maintain that positive change for their nervous system. Okay, so these are good things. That's what we want to look for. All right, but when we start to look at these things, we're going to see these different numbers pop up. The first one is time domains. A time domain is looking at that actual time difference between R-R intervals. So that's what we talked about way in the beginning of this presentation, and those can be represented in one of two ways. The RMS-SD or the SDNN. And we would always prefer to see that RMS-SD. That is the more common measure. And especially when we talk about short-term measures, RMS-SD is going to be a better measure to use. SDNN is proving itself well, but it's better used over a 24-hour measure. So most devices, with the exception of Apple, will measure in RMS-SD. Okay, that's what you're going to see. So Whenever you get your HRV on pretty much any device, it is actually just an RMSSD number, especially if it says milliseconds. That's what we're talking about.

That's it for today's episode. Be sure to tune in for part 2 of this training where Dr. Hopper will discuss HRV trends in various populations. Such as athletes and individuals under high stress. We will also learn how to use this data to measure visceral stress and how to optimize care plans based on HRV data you've gathered. You won't wanna miss it. Episode 80 drops in 2 weeks. Be sure to check out our show note for a link to the full webinar featured in today's episode, as well as any links to special offers from our sponsors. We'll see you next time. Hey guys, if you like what you heard today, I encourage you to visit our website at factor-store.com. That's spelled F-A-K-T-R hyphen store dot com to find out more information about all that we have to offer. We have a variety of online offerings as well as our hands-on Factor Rehab System course scheduled in cities around the globe. Be sure to also check out our event calendar and bookmark any of these upcoming live webinar dates coming up in the near future so you can join us live. And of course, the biggest compliment we can receive. is for you to help us spread the word to your friends, colleagues, and classmates. You'll find all the important links as well as info about our sponsors in the show notes, so be sure to check those out.