[00:00:00] Speaker A: Welcome to the Heart Rate Variability Podcast. Each week we talk about heart rate variability and how it can be used to improve your overall health and wellness.
Please consider the information in this podcast for your informational use and not medical advice. Please see your medical provider to apply any of the strategies outlined in this episode. Heart Rate Variability Podcast is a production of Optimal LLC and Optimal HRV. Check us out at optimalhrv.com Please enjoy the show.
Welcome friends. The Heart Rate Variability Podcast. I am Matt Bennett, back here today with a dear friend of the show, Dr. Fred Schaefer, to talk about a subject that I have been obsessed with, Dr. Schaefer, to say the least.
So welcome back, my friend. For those that might not have caught past episodes, and I would really encourage two of my favorite episodes of all time have been the ones we did on Time Domain and Frequency domain.
I think they're a couple years old now, but I still repost those from time to time because, well, it's an absolute masterclass in HRV. So Dr. Schaefer, welcome back to the show.
Just again, for those that might not have caught our past episodes, let's do just a quick introduction of your yourself and you know, a little bit about your work in hrv, which I know could take three hours to get through. But, but just a brief intro for. For those that may not have listened to past episodes, the short version.
[00:01:42] Speaker B: I've taught at Truman State University for 51 years.
Our lab, the center for Applied Psychophysiology and Biofeedback, has been in existence for about 48 years, give or take.
Our primary focus has been on studying methods to increase healthy hrv.
And much of our recent work has been inspired and is based on the landmark research done at Rutgers by Paul Lehrer, Yevgeny Vashilo, who sadly passed away a number of years ago in Branya Vashilo, a physician who was his wife.
And so this is, you know, the, the question you raise about the low frequency, high frequency ratio is an important one.
And I think it's been a source of a lot of misinformation in the field as well as it certainly has misdirected research in the field.
[00:03:13] Speaker A: Yeah. For those listeners who might not be aware, I did publish, I don't know, the closest thing I've ever published to a manifesto.
And I'll kind of set this up because to have your expertise and your historical perspective, I can't wait to pick your brain on this. But one of the things I've been really concerned about, it's kind of twofold one is as somebody who looks at peer reviewed journal articles, I try to hit anyone that I can get my hands on.
I'm not saying things don't slip through the cracks, but you have to be pretty good to avoid my scope. And then we do the this week in HRV episodes and newsletters on that. And one of the things that just has really started to worry me is the continued use of low frequency, high frequency to justify research outcomes. And one of, I mean one, it's bad for the paper, it's I think a bad reflection on the peer review.
But then the next person that comes along and writes an article gets the article that uses it and may assume that, hey, I found three articles where low frequency and high frequency were used by researchers to measure hrv and then they use it. And then a consumer app person goes into the research and sees low frequency, high frequency as a marker of sympathetic activation and they create oftentimes their most forward facing metric will tell you how sympathetically or parasympathetically you're active. And so that's my one man sort of mission to try to get up on the Google algorithm. So bad information isn't put in the first five categories there. But I would just love Dr. Schaefer, knowing your history with HRV.
How do we get in this mess in your opinion?
There never seems to be a point in the literature that I found that like somebody said, this is definitely sympathetic activation. But I'd love to just get your, you know, historical perspective on how we get into this mess in the first place.
[00:05:49] Speaker B: It's always hard to backtrack and determine when a myth took hold in the field.
There is of course a herd mentality in research, but also in clinical work in which you follow the opinion leaders and you don't question the opinion.
I think that we start with a misunderstanding of what low frequency power obtained over short periods of time really represents.
And this isn't entirely pinned down yet.
The best guess is, and a lot depends on what the person is doing at the time. So the measurement conditions, the breathing rate, the breathing depth, posture, are they sitting, standing, lying face down, lying on their back, all of these can influence our measurements.
But having said that, it is very likely that when you're in a resting condition, sitting quietly, that there is no or virtually no sympathetic contribution, full stop.
So what you're looking at is regulation of blood pressure.
So that is the baroreceptor reflex.
And you may be looking at the contribution of the, to some degree of the parasympathetic system.
So it's clear to me that under short term conditions, and this is an important distinction, long term, meaning 24 hours or longer, there certainly can be sympathetic contributions.
And that is due to the fact that we have a circadian rhythm. It's due to the fact that we have exercise. We face stressors throughout the day.
So long term there can be a sympathetic contribution, but short term, which is what we're talking about in most of the literature, it's largely barore receptor reflex.
[00:08:50] Speaker A: Yeah.
[00:08:52] Speaker B: Does that help?
[00:08:54] Speaker A: It does. I, I think the one thing I'd like to follow up with because there's, there's a couple different ways people talk about this and that's that sympathetic contribution of, you know, I, I'd love to live in the world where low frequency and high frequency ratio measured sympathetic activity. It would be a fun world to live in because, you know, I also hear different, you know, sort of ways of talking about this. Are we talking more when we talk about sympathetic contribution, Are we talking about vagal withdrawal that allows a little bit more of the sympathetic activation or are we talking about some of this happening like on the SA node in the heart? That's, you know, when we, when we use these terminologies as it applies to the sympathetic.
Are, are we ever, I think we see sympathetic activation in the bear reflex, maybe, but not like time domains. But I just love to get any clarity from you on, on this, you know, issue that you hear talked about many different ways.
[00:10:07] Speaker B: Okay. Again, in short term measurements, you're looking at two things.
Regulation of blood pressure via the baroreceptors and breathing at slower rates than we normally breathe.
So we're talking at rates below eight and a half breaths per minute.
And typically, especially if you're using the current protocols for training, somewhere between three and a half breaths per minute to perhaps seven and a half or so.
And those are the major contributors.
And you know, there isn't a sympathetic contributor when you monitor peripheral blood flow.
So for example, blood volume, pulse from the digits, temperature from the digits.
When you measure skin conductance or potential activity from the eccrine sweat glands in the fingers or the palm, and you don't see any evidence of sympathetic activation. So the, the blood flow is normal, it's not reduced, and the palms or the fingertips are not moist.
If you don't see those, it's hard to make a case that there's sympathetic activation.
Now you asked about very low frequency activity in the context, actually in the context of vagal withdrawal.
When we see suppression of the vagus firing, we call this vagal withdrawal.
And this may be reflected in short term measurements of HRV in the very low frequency range.
That's about. And this is, these are very microscopic numbers, 0.005 Hz to 0.05 Hz.
So this is really slow.
This is a range that is also seems to be involved in oh, vascular control.
The, the vasomotor tone reflex that controls blood vessel diameter, probably the intrinsic cardiac nervous system, which means the brain on the heart as opposed to the brain on the gut.
So vagal withdrawal, meaning the reduction in vagus nerve, meaning parasympathetic firing, is probably going to be seen as a bump in power or energy in this very low frequency range. It is not sympathetic, full stop. It is not sympathetic.
It is simply a inhibition of parasympathetic.
[00:13:35] Speaker A: I love that.
So one of the things that this leads me, and since I've got you on the podcast today, I've got to kind of, I'd love to follow up on this, is the idea of sympathetic, you know, at the top. And I hate that we just label sympathetic fight or flight because I mean it's a huge part of our autonomic nervous system that does a lot of good things. And like I tell people, when you're sympathetic shuts down, you're dead. You know, you need it to, to keep living. But, but one of the things I learned recently is that it has a long activation under I think non threatening situations. So I think some people, because of the fight or flight response is a pretty immediate response.
You know, and I was guilty of this too. I would assume vagal break pulls off HPA axis norepinephrine cortisol spikes and in a fraction of the second your sympathetic is active and ready to go. And, and then I learned, well, no, it's, it's more of a slow activation system that might get injected with a bunch of chemicals that get us the fight or flight response. And I love with your expertise, how do you look at the different aspects of sympathetic. Maybe energy is, or you know, where it is operating all the time. And yet we do get to the fight or flight intense experience as well.
[00:15:11] Speaker B: Okay.
Whenever you engage in exercise, this is, this activates the sympathetic nervous system.
And so even getting off the couch. Yeah, so you've been laying on the couch and now you get up to your feet.
That is some that requires a sympathetic adjustment because these are moment to moment adjustments to ensure that we have sufficient blood, for example, to the brain or else we would faint.
So the way I think about sympathetic is there is a very fine tune dynamic adjustment of all of our major organs by way of the autonomic nervous system.
As our dear friend Dr. Patrick Steffen at Brigham Young University has said, when talking about stressors, we often think that stressors either happen or they don't, when in fact it's more like a dimmer switch.
In the same way we have dimmer switches for sympathetic and parasympathetic activity, we are continually adjusting the level of sympathetic firing and parasympathetic firing to provide that fine tuned adjustment for the purpose of homeostasis.
Now, when you talk about fight or flight, this is a very different animal because this really is a brief event that requires. It's sort of an all hands on deck.
[00:17:25] Speaker A: Yeah.
[00:17:26] Speaker B: And you may not experience fight or flight throughout your day.
[00:17:31] Speaker A: Right.
[00:17:32] Speaker B: And one of the points that Stephen Porges has made is that what we often confuse for fight or flight is vagal withdrawal, that our stress response can be vagal withdrawal as opposed to an all hands on deck where we're preparing to fight the saber tooth tiger, which in most cases would be a really dumb idea, or run from it, which would also be dumb.
You're not going to succeed either way.
So the point I would make is that stress is a continuous part of our day.
If we think of stress as perceived challenge as opposed to a existential threat or psychological threat. If you think of stressors as challenges, we have challenges throughout the day and they wax and wane.
And sometimes the response to challenge is sympathetic, other times it is vagal withdrawal.
[00:19:00] Speaker A: Yeah.
[00:19:01] Speaker B: Other times it is increased vagal activity so that you actually, as part of your stress response, may, for example, lower blood pressure.
And so you might feel dizzy or faint, you might increase GI tract activity, and so you may have to go to the bathroom more often than God intended.
These are parasympathetic stress responses.
Conflating stress with sympathetic is a misunderstanding of the full range of our response.
[00:19:49] Speaker A: It's just so beautifully said because I think as the humble mat, I might be able to inject and steer the low frequency, high frequency conversation just because most people. When you say the low frequency, high frequency ratio, if you're not listening to this podcast at least probably have no idea what we're talking about. So. But you know, one of the things I just hear, oh, almost on a daily basis, and this is like in books that are written by very smart people podcast where they're interviewing very smart people is like, oh, people are in fight or flight all, all day. And I'm like, you would be dead probably pretty quickly if you were in that state of arousal for 12 hours. Like, you know, because again, the saber tooth tiger is either going to eat you or you're going to escape. You know, it's not, we're not designed for it to chase us for 12 hours because.
[00:20:48] Speaker B: No.
[00:20:49] Speaker A: So that. But it's, it's so prevalent in society that I, you know, like I said, I'm not gonna. Humbly. I know I probably can't have impact on that, but it's just, I think it does everybody a disservice when we say you're in fight or flight all day at work every day. It's like, yeah, make a withdrawal.
Such a better way to look at this.
[00:21:14] Speaker B: Yeah, yeah, I think that's more realistic. And the way we could know is look at, as I said, look at heart rate.
Is it increasing markedly?
Look at peripheral blood flow. Is it reducing markedly?
Look at sweat gland activity. Is it increasing markedly from your resting values?
If those things aren't happening, we're not looking at sympathetic activation.
And again, I think that's a matter of conflating the stress response with sympathetic change.
[00:22:00] Speaker A: Yes, yes.
[00:22:02] Speaker B: And the problem with, okay, not the problem, but one of many problems with calculating a ratio is that it doesn't tell you anything useful in short term recordings.
You're making assumptions about what goes into that ratio.
And the assumptions are mostly being made about low frequency.
[00:22:33] Speaker A: Yeah.
[00:22:34] Speaker B: Making assumption that the low frequency contains a lively sympathetic component.
[00:22:41] Speaker A: Right.
[00:22:41] Speaker B: Under conditions that there's no evidence that it does, that there's no reason to believe that it should.
So if you want to know what, and I understand that it would be nice to know what your autonomic balance
[00:22:58] Speaker A: is, it would be great.
[00:23:00] Speaker B: It might be useful information.
But you already can more cleanly measure, say HRV and parasympathetic activity two different ways. One way is measure your resting rmssd.
That is a very widely used time domain.
Metric time domain means it is giving us a snapshot of the average amount of heart rate variability in the time we're recording.
The RMSSD gives us a fairly robust measure of heart rate variability.
Then you can measure low frequency power and high frequency power. People are breathing at normal rates, like over nine breaths, perhaps 24 breaths.
And the natural lock, the log to base E of high frequency power is a proxy for vagal tone.
It isn't identical with vagal tone, but it is a good estimate.
These are better measures than this silly ratio that was really based on 24 hour recording anyway, it makes a little more sense over 24 hours in which there undoubtedly is going to be some pronounced legitimate sympathetic activity.
But over 2 minutes, 5 minutes, you're unlikely to see any sympathetic contribution.
So essentially it's high frequency power divided by high frequency power.
And so it's just essentially blood pressure, regulation and breathing.
That's what it represents.
[00:25:24] Speaker A: I love that.
One kind of final question before we wrap up this topic and move on to another one I'm excited to talk about is there.
I just worry about the science we both love and you've talked about 50 years.
I have a little less than that. But eventually, hopefully I can get there too.
I mean, I feel sorry, I don't know, I feel sorry for the person that publishes the article because I'll see quite a few articles where low frequency, high frequency is the only metric that supports the hypothesis.
Yeah, and I'm all about a null result, like give me a result, I'm going to sing the praises of the study. But it gets, the researcher doesn't pick up that it's an invalid metric.
The peer reviewed process doesn't pick up that invalid method. I sort of feel bad because, you know, you published this research, you went through peer review and yet we're just continuously as a field publishing bad results.
And do you have any ideas of how we could stop this? Like, you know, is there, is there any kind and gentle Dr. Schaefer sort of ways that, that we could, you know, sort of confront this issue that I really believe is hurting our field in some fairly significant ways?
[00:27:20] Speaker B: As with so many things, it takes a village and it takes time in.
What that means is that we have to keep educating in the ways that we have available to us.
I think I, I can look back to Paul Lair in 2012 in which he raised his concerns in personal communication about how low frequency power has different meanings depending on the measurement conditions and the activities.
I think that what you do is you keep doing your best to educate the public.
Many years ago I wrote a review article with Roland McCrady and Christopher Zur. It was in Frontiers in 2014 and it was called A Healthy Heart is not a Metronome.
And we addressed this mis, this misunderstanding at that time.
Jack Ginsberg and I wrote a follow UP article in 2017, an overview of heart rate variability, metrics and norms. And we again addressed that issue.
You just keep trying to educate the public in and also the scientific community and you hope that over time that the message will take hold.
I know that every time that Don Moss and Ina Hazan and Paul Lehrer and Dr. Richard Gewirtz teach the BCIA Heart Rate Variability Workshop teaching the didactic for HRV.
This is one of the issues we address and it's our hope that the attendees will leave understanding that this ratio is controversial.
[00:30:06] Speaker A: Yeah.
[00:30:06] Speaker B: And ultimately the best gatekeepers in the literature are the reviewers and the editors.
If your reviewers and editors don't understand the issue, then articles with these claims will get through the cracks.
[00:30:28] Speaker A: Yeah, absolutely. All right, let's shift a little bit. Thank you for that because one of the ways that I hope to continue what I little I can do against this issue is talk to folks like you, get this out as far and wide as we can. And again because I was googling low frequency, high frequency ratio and the first result was pretty balanced. The second result, you had to go to page three to hear how they're it does like three pages of looking at how it is a measure of sympathetic activity. And then oh, this is a little controversial in the research like so you know, if you don't read until the end of the article, you don't kind of get those pieces out there. So hopefully getting content out there will help that if a researcher is interested in HRV and they do a Google search that at least three of the top five results provide that warning for folks that this should not be utilized in the way some people are utilizing it. So I appreciate that. Which then also leads to the second thing I wanted to talk to you about today, which is Mentor.
So one of the go tos in my just workflow now and this topic really I went straight to Mentor and I'll let you explain what Mentor is because it is a great check for my thinking on HRV.
I've got that paid ChatGPT subscription so anytime I'm getting frustrated with something, I go to Mentor. I find it the best check. Even though regular AI can do a pretty good job on heart rate variability, I just find that what you've created is sort of my peer reviewed person. Like I check, I check it, double check it with Mentor before I make statements or conclusions. So I'd love for you to describe because I have no idea the thought behind us, the process behind this. I just wanted to alert the HRV nerds out there like us who listen to this podcast of the great resource you created. So I'd love to hear the the origin story and kind of get an idea of how our, our listeners could, could use it as a tool.
[00:33:08] Speaker B: Okay.
When ChatGPT created the opportunity for users to create their own specialized versions of chat.
We jumped on that and we
[00:33:33] Speaker A: start
[00:33:34] Speaker B: out in with all the ignorance and misconceptions that the AI field is rife with.
So many assumptions proved to be false, so many hours wasted.
This is the takeaway.
We created Mentor as a free resource that you can access even without a paid chat subscription.
They limit you in the number of questions you can ask a day, but you can still use it without a paid subscription.
And we, we basically took a year to train it.
And by train it I mean uploading documents in a form that it could read that synthesized the peer reviewed literature.
Yeah.
So we were, it was very important that we not upload Fred Schaeffer's opinions.
I don't want to propagate misinformation, but I did want to promote science.
And so for many different subject areas, biofeedback, hrv, biofeedback, neurofeedback, breathing, we created specialized documents in that synthesized peer reviewed findings that Mentor could access, that was actually required to access. So if you have a query and it says this canonical document shows blah blah blah, it means that it is referencing a document that we have prepared for it as opposed to going out on the web.
Yeah.
[00:36:00] Speaker A: And I, I just find it, well one, I, I do, it's funny, I, I, I find your personality in it. I don't know if that was intention, intentional in any way shape or form, but there's, there's a level of subtle humor that knowing that you're, you're one of the, the forces behind it, I, I just feel like, you know, if I don't have access to, to Fred at the moment, I, I kind of have access to Fred. And probably that's more of a compliment of the, the fact that I, I, with my knowledge I'm really getting informed results and a chat bot that also references really well too, which isn't always the case with regular chat. So I just appreciate, I did, you know, a you know, kind of out there presentation at APB this year around Piezo to receptors and Mentor was one of those that, you know, knowing that there was a lot of research on HRV and PIEZO2 receptors, you know, it gave me a really good sounding board about sort of what I could and what I couldn't say and whenever I asked for references to back it up, just did an extremely good job of providing those, those references which were actually real, which again is always the case.
[00:37:28] Speaker B: There are, One of the things that we've done is first of all installed guardrails one of those guardrails is check your references for accuracy as well as the possibility that you shamelessly made them up out of whole cloth and that that is just one of the guardrails.
You talked about personality in Mentors operating instructions.
I have guided it as to the way it should approach any query in the sense of it should be kind, it should be balanced, it should be supportive that that was so there is that psychological component because we.
I want.
I want it to be Mentor. I created Mentor to be a 247 on demand personal tutor.
[00:38:49] Speaker A: Yeah.
[00:38:50] Speaker B: And you don't want a tutor who's going to be cold or snarky or judgy. You want a tutor who will be respectful and will and will meet the person where they are rather than where Mentor thinks they should be. Yeah, as if I could think so.
Mentors operating instructions are to be kind and are to be a helpful, respectful tutor on a far on a large range of topics. It's also supposed to tell the person when it has no idea, when it doesn't know.
[00:39:42] Speaker A: Yeah.
And it does with Piezo two. Like yeah I think I asked it how do I train my Piezo 2 which you know is not necessarily something that is validated by any science. Or is it do you even want to train your Piezo 2 is probably the better question and it did give me some answers but it gave me the caveat to say that there's nothing solid out there in the research but then you know, get good sleep, get some movement in like so which all really makes makes sense. But. But it's that caveat that you don't often get with AI that both a lot of AI wants you to like it and make sure it does give you something even if though that might be junk and Mentor avoids avoid that which I really do appreciate. Yeah.
[00:40:39] Speaker B: So you can go into chat and chat will give you the option to look for other GPTs and among those will be Mentor GPT and it will be one of the most frequently used sources for biofeedback and neurofeedback in HRV biofeedback information.
And we don't.
We designed it to support our larger mission which we share with Optimal HRV which is not selling widgets, not selling software, but rather providing education.
My company's always been guided, just as Optimal has been guided by our mission.
Our shared mission is to elevate the level of HRV education and to get useful information into the hands of providers and their clients.
And so that's. That is part of the purpose for For Mentor.
Now, Mentor is AI.
As a result, it can dispense with its guardrails on a second's notice.
I discovered that with each new release of chat, and I assume these are the major changes, not the very tiny ones, you have to re upload its core documents or else it will not consult them.
[00:42:49] Speaker A: Really?
[00:42:50] Speaker B: Yeah. And they don't warn you about that. So it's like there is a set of rules that you only learn about through experience.
[00:43:01] Speaker A: Yeah.
[00:43:02] Speaker B: So when I saw that it wasn't consulting the resources that I provided, I realized that with each major change I had to reinstall them.
[00:43:18] Speaker A: Fascinating.
[00:43:19] Speaker B: So I did. And as soon as I saw it referencing the canonical, meaning the core documents, which I keep handy in a folder and then update over time, I knew it was working properly again.
Yeah, it was still doing well even without the canonical documents.
[00:43:42] Speaker A: Yes, yes.
[00:43:43] Speaker B: But it does better when it can cite them.
[00:43:46] Speaker A: Yeah. And it's just for our listeners, if you haven't used it, it's really like we've been talking about ChatGPT.
For me, it's my go to for HRV specific stuff. Especially when you get into things like the low frequency, high frequency ratio controversy. That's where it really. Because it's not trying to make a, a real as bad. I mean it's still balanced but it's giving you, it's working off those documents of the peer reviewed, you know, Fred approved research that, that really takes you another step or two. What you can get off the general chat or you know, you don't have to put in all the fundamental documents because you all have done that for us already with Mentor.
[00:44:38] Speaker B: Yeah, I, that's the point.
I've done and will continue to do that background research.
So that, and I use it to, I use it as my personal tutor on the many topics in which I don't have a deep background. Yeah.
And so, but I, in full disclosure, I use a number of different AI platforms.
I am increasingly impressed by Claude, AI by Anthropic.
I use Gemini.
I believe they have different strengths and different limitations.
Yeah, but, but no, if you understand the limitations of the AI platform you're using and if you are willing to carefully curate the results so that you are not misled by a hallucination, you should be fine.
[00:45:52] Speaker A: Yeah. Yeah.
Well, thank you again from a user of Mentor. That has been just a great resource for me and I know sometimes I'll get on the conversation with another HRV nerd and we will actually pull Mentor up if we hit some questions. So like you said it can be a really good coach in the moment, too, where we don't have to go down a rabbit hole of this, you know, of our thinking. Being off mentor gives a really nice check to where the conversation's going. So just appreciate this gift, among many others that you have given to both me and the field at large. So I really appreciate it.
Yeah. And Dr. Schaefer, again, thank you so much. I always love our conversations when we get on here.
We were talking beforehand about you spending time with some neighbors this morning. And for. For me to have you, even though we're a few thousand miles apart, just to be able to connect with one of my favorite people, at least my neighbor in the field and a friend of mine today is always just a joy. So thank you so much for again, your work, your. Your dedication, the mission, and again, sharing your expertise with our audience.
[00:47:24] Speaker B: Oh, my pleasure.
[00:47:27] Speaker A: And as always, you can find show notes information on Dr. Schaefer's
[email protected] and we'll see you soon.
