[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.
[00:00:29] Speaker B: The show Muscle contraction based HRV biofeedback, often referred to as rhythmic skeletal muscle tension or slow paced contraction, aims to stimulate the cardiovascular system's baroreflex at its natural resonance approximately 1/10 of a hertz. The idea is straightforward. Brief rhythmic whole body or multi limb contractions at about six cycles per minute create 10 second waves in blood pressure and heart rate, engaging the same closed loop barrow reflex mechanics that underlie resonance frequency breathing.
Foundational laboratory work shows that contracting at 0.1 Hz produces pronounced oscillations in heart rate, systolic blood pressure and pulse transit time. With increased power at 0.1 Hz and tighter coupling between heart rate and blood pressure fluctuations, signatures of baroreflex mediated resonance in these experiments mean systolic pressure and vascular tone variability tend arise more than heart rate variability during the tension periods consistent with the hemodynamic load of isometric effort rather than a purely vagal phenomenon. Frequency and muscle pattern matter A randomized within subject study that compared 1, 6 and 12 contractions per minute foundation that 1 in 6 contractions per minute significantly increased multiple HRV time domain metrics, low frequency power and nonlinear indices compared with 12 per minute and the peak spectral frequency clustered near 0.10 Hz at the 6 per minute pace.
Subsequent work indicates that recruiting the core and gluteal muscles and in some protocols crossing the legs can amplify resonance markers such as heart rate, max min and and low frequency power compared with wrist and ankle contraction alone.
Conceptually, this aligns with the broader resonance frequency model. The stimulation rate, not the specific modality, determines the resonance response. Slow breathing, rhythmic emotional stimulation and rhythmic muscle tension can each drive a 0.1 Hz peak when paced at the individual's resonance because all three perturb the same baroreflex linked control loops for heart rate, blood pressure and vascular tone. The hemodynamics side of the literature provides converging evidence outside of HRV biofeedback settings. Leg crossing and muscle tensing maneuvers reliably raise cardiac output and arterial pressure and improve cerebral oxygenation during orthostatic stress or impending vasovagal episodes. These findings don't measure HRV directly, but they support the mechanism by which rhythmic contractions can modulate baroreflex related oscillations.
Related but distinct evidence comes from isometric hand grip training where weeks of brief isometric bouts lower resting blood pressure and show mixed effects on HRV across trials. That body of work demonstrates autonomic and vascular adaptations to isometric loading but reflects exercise training, not moment to moment resonance entrainment via biofeedback. Overall, the research base is most substantial for acute physiological entrainment.
Rhythmic contractions near 6 per minute reliably boost 0.1 Hz oscillations and baroreflex linked coherence in the lab with some muscle patterns producing larger effects. What remains understudied are head to head clinical trials versus resonance frequency, breathing, long term outcomes and individualized frequency tuning for contraction based protocols. The current takeaway is that muscle driven pacing is a viable non respiratory pathway to to the same baroreflex resonance targeted by standard HRV biofeedback with promising but still developing evidence for clinical translation.
[00:04:31] Speaker A: Welcome friends to the Heart Rate Variability Podcast. I'm Matt Bennett and I'm going to do a solo episode today based on the research that you just listened to around muscle contraction. So I want to talk to you a little bit about how I'm integrating this research into my own practice and maybe give you some ideas, some thoughts that you can integrate it into your own practice as well. So also in the show notes we'll link a link to the articles that we use to create the introduction there. Also with my past episode with Dr. Fred Schaefer where he talks about his research with muscle contraction as well. So I want to be very clear as we enter this conversation for this episode is that I'm basing my suggestions and you know, if you're curious about this, trying this out based on research and yet at the same time I'm taking that research and applying it in a way that there's not been a meta study done on what Matt is doing. So I'm always very clear is research based but not necessarily yet research supported. Now I'm also not going against any research, but I always am clear. This is that research based speculation. And so does it work for you? And if you're curious, you know, and it's safe for you, I would say it's probably safe for most people, but if you have any chronic illnesses, heart conditions, like I said, before you start anything, you should probably talk to your medical Provider. So make sure it's safe for you. I think for most people it probably is. But obviously if you feel uncomfortable or it's, you know, feel dizzy or something like that, you know, stop immediately with that. So with that said, when you look at, you know, the research which I found fascinating originally around muscle contraction, it gives us an alternative to breathing is we can get in, we can use contractions on our residents frequency to increase, you know, low frequency HRV and really do HRV training or while breathing at a normal rate. Now for certain medical conditions, this may be a really useful tool.
Also, I know my work with individuals with trauma, breathing isn't comfortable, especially focused breathing and breath work is not really a comfortable and can be a trigger for folks. So for those that may have trouble physically or psychologically with breath work, this is a spectacular alternative. So it gives us that way to introduce HRV biofeedback to folks who might not be comfortable with breathwork. The good news is I think most people are comfortable with breathwork, but you know, there's a population that does struggle with it. So this gives a real simple entry and safe entry for folks that might struggle with breath work. So if you look at Dr. Fred Schaefer's work, which I think you need to, if you're interested in this topic, is there's a, there's a position that people kind of traditionally have used and that's someone sitting up in one chair with their legs up on another chair. So their legs are kind of straight in front of them, their legs are crossed. And so basically at their resonance frequency breathing rate, they're contracting and so they squeeze in on their hands and their forearms flex and then they bring their toes towards them. So they're flexing their calf as well. And it's a fairly gentle flex. And then you know, if you think about using a breathing pacer on the exhale, you release that. So you know, on the contraction you're pumping blood into the system on the exhale, you know what would be the exhale? But it's the relaxation that blood flows back into the body. And so one of the important things here is if you're tracking HRV during these contraction activities, you don't want the sensor to be on the part of the body you're contracting that will probably end up in giving you artifacts because there's movement involved. So if you're using, you know, a polar strap or a chest strap, you're probably good to go unless you're moving your chest a lot, which you know, most of these, you're not going to be doing that. But you can also put the. If you got the optimal HRV sensor, you can put it on your upper arm as well. Kind of have it on the inside of the upper arm, you know, and you're doing those, those contractions with, you know, without introducing a ton of artifact in there. So, again, pretty, you know, solid contractions, you know. So on the inhale, what would be the inhale, you can track. On the exhale, you relax. And again, the exciting thing is that this, you know, helps increase low frequency. You're doing HRV training without. While breathing at a normal rate. Well, you know, you get this research and you get a nerd like me who's like, you know, okay, well, if breathwork helps you get into resonance frequency or optimal zone, if you're using the HRV app, and if you're not, that just means your low frequency is dominant. It's the percentage of time your low frequency is dominant over the last minute of time. So we call optimal zone 80% of above. But we give that percentage marker to say, okay, how much of the time in the last 60 seconds have you been in that low frequency range?
And so I'm going to say, okay, if breath work helps me get there, if muscle contraction helps me get there, what if we put those two things together?
So I'm going to talk first about my evening practice. So my evening practice, because that's probably what normal people do, is I sit, as my wife says, second grade teacher, crisscross applesauce. I can't get my legs on a pretzel like some of the yogis do. So. So I just got my legs crossed. I've got my, you know, my hands on my, my knees. Kind of the traditional meditation roll. Without the pretzel, your foot's up on your leg. You know, I'm, I'm just not flexible enough.
I. I'd love to do that. At some point, they'll think I'm going to get there. So, so I'm in that position.
And so what I do is on the inhale, I contract my pelvic floor. Now, pelvic floor, there's biofeedback, specifically using the pelvic floor. It is a powerful, you know, if you look at, you know, chakras, there's chakra down there, you know, but we've got this from a scientific perspective, is a pretty powerful part of our body, really, to push through the blood. You know, when I was doing Q Gong, you know, we focused a lot on the pelvic floor and pelvic floor contraction. And if you got a 13 year old boy that lives inside of you like I do, you might chuckle when I say this.
But you know, when I, when I talk to. Okay, how do you contract your, contract your pelvic floor? Like it's not a area of the body I've really ever thought too much about. Again, 13 year old boy inside me maybe, but since I was 13, not a whole lot of thought to that area.
And so the best way to, you know, flex your pelvic floor again, you can chuckle here with me is like if you think about, you're, you're taking a pee and you stop the string, right? So there's that contraction there and then. And I think these two go together really well. It's like you got a fart but you got to stop that fart. So there's kind of a little bit from behind, a little bit from in front and that's a pelvic floor contraction. So you can do a little bit. Maybe I'm doing it right now. Or you could do really aggressive pelvic floor contraction. So you know, again, there, there's. I always love when our modern science again with, you know, pelvic floor contraction, biofeedback, you know, and you see these ancient practices where, you know, people have been using pelvic floor contraction for health and wellness for thousands and thousands of years. So you know, science, traditional approach. I love those when those two things complement each other.
So on the inhale, you know, again I'm sitting in the crisscross applesauce. Inhale, pelvic floor contraction. I'm pushing that blood pressure through my system. Exhale, pelvic floor releases.
So what I seen because sometimes when, you know, I'm kind of relaxed, I've had a good day, it wasn't too stressful. I can just use my breath to get in optimal zone. Again. 80% of the last minute was in low frequency and stay there throughout my practice. Sometimes that's easy. And if I'm doing it, I don't really feel like I need to do the pelvic floor contractions.
However, this is the thing I love about adding muscle contraction to my own personal practice. On those days where I'm struggling, where, you know, I may be just right at the edge of 80% of time. So I'm going in and out again. What optimal cause, optimal zone. So I'm struggling, I'm just not having a great practice.
If I start to add, you know, pelvic Floor contractions and relaxation. So contract on the inhale, release on the exhale.
It's amazing to watch that percentage go up. You know, this is what I love about HRV biofeedback is does this work for Matt? On those days that I'm not having a really great practice where maybe my focus is off my stress level, the level of stress maybe made my nervous system just struggling to kind of get in that training mode. The muscle contraction, I can just watch that move up and sometimes I will move it up and then I can go back just to breathing and it kind of stays there. So it helps me kind of adjust. It's like passing somebody on the highway. I need this to get where I want to go. So I got to pass you. But then I go back to the speed limit or maybe seven miles above the speed limit once I pass that. So I can. I can use it to get back and then, you know, regain my focus, you know, again. I've never stopped breathing at residence, but, you know, I'm back up there. Other times with practices that I might be just really exhausted at the end of the day, I have to do those contractions.
Every inhale contract, every exhale release to keep me in optimal zone. So, you know, and it is a focused to do. I also find that my mind wanders a lot less when I'm doing muscle contractions. So because I got to focus on the timing, I'm syncing the contraction up with my breath and I'm more focused throughout my practice. So there's a mental side to this as well, you know, and I can't sparse out, you know, what, what is the contraction versus the focus side of it. I'm sure both of those are contributing. But for me, whose mind, you know, the monkey mind is the mat mind, it's always going to wander somewhere. Interesting, fascinating and probably a little annoying for my hrv, you know, really helps me keep that. That focus throughout the practice.
The net. The next thing you know that, that, you know, that I really see is during my morning practice as well. Now, this goes kind of beyond probably even research speculation into mat really playing around. So I would encourage you if, you know, you want to try the pelvic floor contractions or, you know, sit in a chair, have your legs out, you know, maybe just try at first push as on the inhale, bring those toes up to you on the exhale, bring them out.
You might do the contractions as well. Again, if you're using optimal HRV reader and contracting your forearms, put it up on the bicep, tricep, inner arm, upper arm area, just to eliminate artifacts and watch what happens. You know, play around with it, just do the contractions, just do some breathing and then put those two together and see if you see what I see. And let me know what you see as well, because, you know, again, I'm just in of one. I'm studying myself with this, so I would love to learn what other people are doing as well.
So my morning practice, you know, I've studied and I am a student. And I'm not just saying a student to be humble. I'm saying a student because that's the level I'm at. I really was looking for something. And this kind of takes us back to a time where the optimal app did not have sounds to it, so you had to look at the screen. And I was doing Tai Chi Q Gong, but they were all movements that were pretty substantial. And at the same time, you know, you, your, your front moves. So it was hard, if not impossible to look at a screen. Now we have sounds and vibration, so you can do more movement meditation with this. And so I've had, I've had a polar strap. And you know, there, there's. In wing chun, it's called the little ideas. That, that, that's the translation. So I don't butcher the language, but it's the first set in Wing chun is a set where the, like, if you're watching on YouTube, I'm just facing the camera so there's no churning, there's no. Nothing that takes my ability to look at a phone screen out there. And I just love this, what, what they call in martial arts, this form that. That's there. It's very simple. But, you know, one is you're in what's called goat stance. Now, if you can look this up, you don't have to do this. I just take telling you at the extreme that I've taken this to more than anything else. But it's where your, your toes are pointed inwards and you're kind of. They call it goat stance because you kind of contract to stay on the goat. I've never ruined a goat. If you can imagine a 6, 7 guy trying to ride a goat, probably something I will never do in my life. But, you know, I guess people ride goats, they squeeze in to stay on the goat, otherwise the goat's going to knock them off. So you can. Again, there's a lot of people that can probably tell you how to do this, right? But it's a way you Know, I find just doing, having done this practice for a long time, it's a great way to strengthen your legs because the first time you stand in goat stance, it's not really comfortable. Now, I can do it for 20 minutes at a time. You know, as easy as standing up. But so on the inhale, not only can I contract my pelvic floor, but I can also squeeze that goat right. So my thighs are contracting. So I've kind of that my whole lower body. Because you don't really leave. You don't leave the goat stance throughout this set, I've got that contraction all through my lower body. Now with a polar strap on, I can move my arms with less artifact. Again, if you wanted to analyze my HRV during these practices, I'm still, because I'm moving, there's going to be artifact in there. So I want to acknowledge that though the chest in these practices stays constantly facing forward, so there's very little chest movement. So I do, I do use that again. If I use the optimal strap, I put it on the upper arm as well. But, you know, I paid 100 bucks for a Polar H10 at some point, so I'm using that during this. Now, with this set, there's a lot of our movements, right. If you think about wax on, wax off, right. This is, you know, kung fu versus karate. So I know, yeah, different, different things. But, you know, there's a lot of movements like that where, if you've ever practiced tai chi, you have a lot of arm movements, kind of punches, but a lot of movements that you can slow down. So what I do is when I do an arm movement, I on the inhale is where I contract.
And when I bring it back, usually to my body, there's that exhale and I relax my entire body. So it's almost because my legs and, you know, pelvic floor are contracted. You know, it's almost a little bit of a drop. And then on the, you know, I get an inch taller on the inhale because I contract and kind of push myself up a little bit. Exhale, I drop. And what I have found with this is that I can tell you the bigger the movement, the more, the less I'm in. It's harder to stay in low frequency.
But what I've really found, and I'll talk about my exhale in another podcast, but getting that contraction. So contracting both of my arms on the inhale, supporting the movement of my exhale contraction again, I'm usually bringing my arms back to my body within this movement. So again, if you've ever seen somebody do Tai chi, you can kind of think through this is low or excuse me, slow movements and doing that at residence frequency with that muscle contraction.
I have found adding muscle contraction to this has just made my morning practice way more powerful. One is, you know, having the ability to measure this with the polar strap has been very, very useful in that, you know, I can see, I can, I know which movements, maybe the more dramatic ones that I'm going to have trouble staying in low frequency. So I need to focus more attention, really hitting that inhale, exhale, mark and maybe contracting a little bit more during those other movements that are more kind of relaxed.
You know, it's usually getting, it wasn't initially, but getting fairly easy for me to stay in low frequency even though I'm moving. And again, I know that there's. For the HRV nerds out there, anytime you move there's the risk of artifact. But again, with my chest area fairly steady, I think I'm eliminating that quite a bit. Just like, you know, in my evening practice when I'm doing just the pelvic floor contractions, there's movement there as well. Now it's far enough away from my, my reader that's on my forearm that I'm probably not getting a ton of artifact in there, but at the same. So I'm, I can trust that data as well. So again, a 16 minute practice in the morning where I'm really using that contraction along with the breathing with very intentional movements. Focus, focus and focus Again from ATS monkey mind.
Those have been really good. So again, you know, really finding and playing around with it again, make sure it's safe for you to do this, but really playing around and finding what works for you. Again, we got enough research to back up that we could do HRV training without breath work, which I think is really fascinating.
We know breath work helps us get in resonance frequency is a great vagal nerve stimulator to get us into low frequency. So combine the two and see. Like I said, even with my morning practice, if I start to slip down out optimal zone, a real good contraction, really paying attention to the timing of it can help me get back into that ideal training state. So again, it helps me correct when I'm starting to slide out and get back in there as well. So I would love to hear if you give this a shot or you're doing any muscle contraction work, please reach out to me. This is, you know, if you're doing this while, you know, the research has been around on this for a while now. It's still relatively a novel approach just because we focus so much on breath work. So I would love to learn from you as well. So you can always email
[email protected] let me know your story.
Maybe what you're doing can help me with my practice as well.
The final thing here is we know, and I don't think it's going to surprise anybody of progressive muscle relaxation, right? So this is another thing that's been around for a long time and this is where I think some of the research around those progressive muscle relaxation, which is why I love the contractions to help me kind of wind down at night.
I find that really good as well. Even though I'm just contracting my pelvic floor, my quality of sleep, especially time to sleep, has just drastically improved since I started doing that 10 minute evening practice. So again, progressive muscle relaxation can be another way to do this. Do that at your residence frequency breathing rate. Right. And if you want to throw your breath in there too, great. But again, track it, see, work with it and let me know how it goes. So as always, thank you for joining. Again, show notes are really important with this episode because the research that we presented at the beginning as well as some of the research that I'm building sort of my practice off of as a foundation, again, I'm kind of pushing that beyond its current understanding. But hey man, if enough of us start doing breath work and muscle contraction, maybe that meta study won't be far away. So anyway, thank you so much for joining us and we'll see you soon.
