Unlocking the Secrets of HRV: A Guide for Athletes

Hello and welcome to the Athletes Compass where we navigate training, fitness and health for everyday athletes. This week, we are talking about heart rate variability or HRV. Paul, you gave a talk in January at the Endurance Exchange Conference about HRV. Could you tell us what you talked about?

Hello and welcome.

Yeah, Paul, hey, thanks so much and welcome everyone. Great to hear everyone. I was very privileged. I got an invite from the endurance exchange team through Trevor Connor of Fast Talk Laboratories. Huge thanks to him. And I was asked to go and speak on this topic because more and more coaches and athletes are wanting to understand how do we use this tool of heart rate variability.

to get insight into making decisions around our training. What does it really mean? So, you know, I think we've talked a little bit about this before, but just for, so everyone's on page, we just briefly review the principles. And the basic principle is that, you know, we have our heart rate. And when I think of heart rate,

I think of the first thing I think about is the Wizard of Oz and the Tin Man and that clock that he was hanging down there because he wanted a heart, right? He didn't have a heart. So remember the Tin Man with the clock. And so you immediately think that your pulse is like this clock that's tick-tocking. And at first glance, it sort of sounds that way, but it's not. It's actually quite...

variable. It varies significantly and that variation heart rate variability tells us a lot of insight into your health and in particular your response to any training or but not only that insight into all the other various different stressors that are inputting into your life from you know psychosocial relationship issues that are stressing you out.

insight into the menstrual cycle that we'll probably talk about in the next podcast, to insight into how hard your training is. And specifically, of course, when you train, that's a big stressor, right? So heart rate variability is a great tool that we know we can use to give a response to the load of training. And regular listeners to the podcast will have

heard about training load, load is another term for stress. And we've talked about this at length with, you know, what things like the performance profile, where you're looking at the fitness and fatigue sort of things, that's great. But as many of us know, we can, any of us can take a blanket plan and we can, you know, we can train to that blanket plan or that blanket session, but two individuals.

you know, say me and Paul, we're going to respond completely differently to that same exact training session. And heart rate variability gives us insight into that individual response to training.

So Andrew Kent, a friend of mine, he asked us, you know, what are the practical applications for using HRV for our training?

Yeah, well, I think that the practical insight that you can get is exactly that. Is really, you know, the how am I individually responding to this training session that Athletica or any program gives you. And that's the first one. But we should actually go even deeper. And this is what I spoke on at.

the endurance exchange conference, I spoke about, really Marco Altini's HRV4Training principles that he lays out. So credit to Marco on all of the stuff that I am rehashing. But basically there's a few key principles that we need to follow when we try to get practicality out of heart rate variability. And...

The first one is that you should never react individually to a single measure. So say you're using a whoop or an Oura ring or HRV4Training , or you name or Garmin. And say you have a low or a high reading. That's interesting insight, but it's not as finite really as

insight that you might get from a training session where it's calculating the load. It's interesting, but what we now realize is that you need to take a more of a Google Earth, big picture look at this data. And the cool thing is that's what Athletica is doing now, because if you go to your

recovery profile on Athletica and you're measuring heart rate variability, you'll actually get this longitudinal mark of your training and your heart rate variability profile going up and down, up and down, up and down. And you're getting what we call this 60 day average, which winds up being like your normal value. So we're taking a lot of data points to find out what's normal for you. We get this normal range.

And then we go a little more granular and we take a seven day rolling average. And if the seven day rolling average, it starts to drift outside of the 60 day rolling average, the long-term one, it's the same principles as the acute versus chronic workload sort of thing except looking at it in a different way. And yeah, and then when that seven day rolling average is either above or below, well now we should start.

you know, hmm, I wonder what's going on here. That's sort of, you know, that's something that now we take, now we wonder a little bit deeper. Could this relate to something? You know, is it related to my menstrual cycle? Is it related to getting sick? Is it related to training adaptation and enhancement? Am I feeling fitter? Ah, interesting, you know, in the context where it's going higher. Now we're getting, this is the real value of it.

for coach and athlete.

So you talked about some of the factors that influence HRV, possible menstrual cycle, sickness, other issues. What are some other things? Does training, you know, does too much training start to factor in into HRV?

Yeah, it could be a lot of different things. So again, remember that train HRV is getting insight. So, you know, again, I should back up, back the truck up a little bit and we should just remind the, we've spoken at this about this in a lot of different podcasts, but we should just make it be very clear. There's two branches of the autonomic nervous system. There's the sympathetic fight or flight and then there's the parasympathetic rest and digest nervous systems.

And when we measure heart rate variability, we're looking at a variable that's got a big fancy term, it's called RMSSD, it's the root mean square of successive differences, right? And it's basically looking at the difference of one heartbeat versus the other heartbeat, right? And that word successive difference, right? So it's like, it's literally capturing, well, what's the difference in this heartbeat? What's the difference in this heartbeat? So it's doing that.

repeatedly and repeatedly and repeatedly. Again, here's where AI kind of comes into it, right? It's getting insight into the differences in those beats. And when there's a lot of difference in those beats, that means the parasympathetic system, the rest and digest system is very, is working hard. And that typically means, I'm saying typically because it's not always, but typically that is an indicator of your...

parasympathetic system, ramping up and you adapting. So you're sleeping, you're probably sleeping really well if you're getting this on a consistent basis and you're adapting to your training. Conversely, if you're more like the Tin Man with the clock around there and it's tick tock, tick tock, right on the beat, that's typically a sign of either you're exercising or you're stressed, right? Exercise is a stress, but if you're not recovering, then that's, you know.

thoughts are racing at night, say for example, your boss is angry with you, your spouse is fighting with you, etc. And think of how wired you feel in these circumstances, right? Like, all of us go through these various different things in life. So think about how hyped up that you kind of are, and you know, either in a good way or a bad way, but that's your sympathetic system, your fight or flight system ramped right up. Well, when your sympathetic system ramps up, it depresses the parasympathetic system.

quiet's down and it's again more like that tin man clock. So where did I go with this? Basically that's the, you know, we're looking at the, we're looking at the, we're getting insight into the central nervous system, the autonomic nervous system. And yeah, and these fluctuations are giving us insight into our ability to adapt to

Thank you.

to stress and the response to exercise, along with everything else around it. What do you think, Marjaana? How am I doing here? What am I missing?

Oh my gosh, you're doing so good.

I'm rambling! Okay.

It's a good ramble. As always, we ask our listeners to send us questions and our friend Cindy has a few of them. So I'm going to ask you, she's saying if each person's HRV value is unique, or is there a certain number we should be striving for?

That's a great question. And I wondered the same thing. And many know that I have a couple good friends friends friends friends of the podcast and in the world and who are experts in this and gave me all my insight insight. The first is my PhD student of the past and that's Dr. Dan Plews. And the other is my colleague with HIIT Science, which is Martin Buchheit who's

really taught me everything. And again, Martin and I co-supervised Dan Plews's PhD, which was done on many, you know, lots of rowers in the New Zealand rowing program. So, and one thing when we were actually measuring these things, you know, you, again, the best process of doing research is to actually do these on yourself first. So when I was doing my own research on myself to get insight into my own HRV, it was really interesting because

I had this really low value and my mates like Dan Plews and Martin, they had naturally really high values. So I was kind of, you know, I was like, well, I thought that high was always best, right? But there are these just these little nuances and whatnot that mean ultimately you're, it's not the case. It really needs to be looked at the individual basis. All that matters is what your value.

really is. There is some, there's this phenomenon called the saturation effect, which applies to me, but I'm not going to go into that. But basically, you could have an individual low value that could be just fine. You could have an individual high value that could be just fine. All that matters at the end of the day is your value and how you're deviating above or below that. And that kind of goes into the diatribe that I, you know,

applied when I was talking about the 60-day rolling average versus the 7-day rolling average. So that's all that matters to you, Cindy, is what's your 60-day rolling average and how does your 7-day rolling average, shorter term, apply relative to your longer term value? So I think that I answered the question there, Marjaana

Well, she has another one. Are you ready for it? Cindy asks, I've noticed that leading up to my leading up to a race my HRV seems to decline and I get the warning to take it easy. This always stresses me out wondering if it's if this is common. Can viewing an unfavorable HRV cause more stress making your HRV worse?

Oh, yeah, of course. I love Cindy's questions.

So do I. Go Cindy.

Can you guys see that? Okay, so I'm pulling up this slide here from the presentation at Endurance Exchange. And look, this is data from a couple of those rowers. Now these are rowers that went on to...

Yes.

do world championship events and also at the London Olympics. And this is all published in Dan's lit review for his PhD published in Sports Medicine there, endurance training adaptation and HRV and elite endurance athletes. So here, like, so Cindy, yes, in the taper, look at the taper, whether it's world champs or it's the Olympics in medalists, the gold medalists from the New Zealand Olympic program. And

pretty much every other athlete that we kind of see. We see this exactly what you describe, Cindy, where you go into a low HRV in the taper phase. This is a good thing and you should actually expect it. You should actually get excited about it. And the reason is, is that you've slowed down with your endurance training.

you've probably increased a little bit of intensity as we often do in the taper period, right? Those high intensity sessions, the primers, et cetera, that Cindy, I know you'll be familiar with as a long time user of Athletica. These are all these sorts of things, there's a reduction in the parasympathetic input to the nervous system, and this allows for the sympathetic system to rise.

So, and this, and again, so a lower HRV and this, and you want this, right? Because now you've made all the endurance adaptations and you wanna drive and perform now. You want that sympathetic system kind of elevated in that phase. So these are, this is always associated with enhanced performance. And again, we see this in Dan Ploos' publications of, you know, just blog reports and whatnot.

that reduction in HRV. Here's Douglas Dugal Allen in the winning challenge Wanaka. We see again, get the reduction in HRV on race day. And it's for that exact sort of same reason. And yeah, in HRV4Training , Kyle Buckingham demonstrating this. We see Yen Van Berkel, all of his as well as the same sort of thing. So there's a very common experience there for that, Cindy.

Great question.

I was listening to the Greg Bennett Show

Absolutely.

And Dr. Tommy Wood was on and he said something interesting. It was like, I really liked what he said. I'm going to just read it. HRV doesn't tell you how well you're going to perform. It tells you the cost of a given performance is going to be. You can still perform, although HRV is tanked. But there's a large cost to that performance. So how you interpret your HRV score matters.

Right. Like if you're an athlete who gets stressed out about the HRV score going down, maybe it's a good idea not to take that on a race day.

Absolutely.

For sure, absolutely. Yeah, if it's gonna stress you out, it's not just put that at park that like we just, yeah, we don't need that in that. And this kind of comes down to the individual, it comes down really to the individual, right? And what they are, their philosophies. And again, this is where coaches like yourselves can assist with these sorts of decisions, right? Right, Marjaana and Paul.

Mm-hmm.

Same with sleeping, a lot of people get stressed out, they need to wake up 3am for Ironman start and then they can't sleep or fall asleep because they are going through the race and there's nerves. But I always say one bad night of sleep doesn't tank your performance, just go.

Yeah, absolutely, absolutely. 100%. And if you don't mind me just sharing one more slide, I really like this. This is a tweet put out by Alan Couzens Many will know he's a lot, highly respect Alan and a lot of the work that he does because he deals with AI. He's a scientist and then he also deals a lot with HRV. So Alan says in a tweet,

This was actually pretty recent, but he says when you're as a general principle or general rule, and then this is in the context of your training, your day-to-day training, when your HRV is high, generally you get your response to training is high. That is you get a high return for the work that you put in. Again, in that context of the seven day rolling average relative to the 60 day rolling average. And again,

when your HRV is low, your response to that training can sometimes also be low. So I think Tommy was a little bit alluding to that in what Marjaana sort of just said. But basically sometimes you can actually be working really, really hard training your ass off, but you might actually not be getting anything in return because when in general, when you are, when that HRV is high,

it's usually sort of this signal that the system's ready to respond to that training and adapt you.

So how do we look at those day-to-day readings? You know, if we get a yellow or a red reading, do we take that day off? Do we look at the trends? What happens when we're feeling really good and we get a yellow or a red reading?

Yeah, I'm really glad you asked that question, Paul, because again, I will revert to the presentation and this is again, some key takeaway points from the presentation. And again, I've stolen Marco Altini's. Now, can you see that, Paul? So yeah, so, and then this goes back to HIIT Science principles, Athletica principles.

Mm-hmm. Yes.

coaching principles context first always, right? So remember that everything is relative and that, so we've just, we've really, hopefully we've nailed that, that the data needs to be analyzed relative to the historical norms. That means the seven day average needs to be analyzed relative to the 60 day average. Always looking at the big picture first. So...

avoid, Marco says, avoid naive interpretation, relax about a single value. That was your question, Paul. If you get a single value that's high or low, interesting, but it's not like we don't change the training necessarily just because of that, that single day. And Marjaana alluded to that as well. So higher isn't always better. Lower isn't always better. We're going to look at that moving seven day average.

And multi-parameter is key. And this is again where we believe that the Athletica philosophy and the AI principles where we're taking lots of sensor data, we're going to be advantaged. So we need to have more data around the big picture context. So let's look at our CEO Mark's HRV rolling averages over the...

last year. So let's look and think, you know, everything is relative. And the big picture first. So look at his seven-day, look at his 60-day rolling average. That's the normal range there. And that is his, you know, that's his 60-day rolling average, which is in the orange. And then we also look to his seven-day rolling average. That's the moving blue line as we see it going

you

RMSSD HRV. Okay, so big picture for it. Now that's some interesting things that are happening on this graph. We see that all of a sudden over here, his HRV tends to rise. Well, it's, you know, and as a coach of Mark, I'm kind of, it's interesting to note that Mark made a significant change to his diet right about here and started following a little bit more in line the Athletica training principles.

And it's, did this, did that contribute to these notable changes and general rises in his seven day average relative to his 60 day average? I don't know. I'd like to believe so. But then Mark, of course, goes to Mexico on a vacation. And what happens when we go to Mexico? Right. Well, sometimes you get a little sick. And indeed, Mark did get sick. And we can see that his rolling seven day average.

relative to a 60 day rolling average tends to drop down there. And again, with knowing how this works, I kind of think, oh, that's probably what we would expect. So that's how I kind of use individual versus rolling the seven day rolling averages. And this is all available on your recovery profile for Athletica. So I hope that answers some questions there. Paul.

It does. So Craig Morfit, another friend of mine, and I'm training his son right now, he asks if there's a connection between HRV and aging athletes. Does that make a difference? Does age affect HRV and is that something we need to keep in mind when we're analyzing our data?

Yeah, it's a good one. So for all of us, Paul, we're all, yeah, we're all aging. We're all getting, but many of the listeners will have heard the differences between your chronological age, right? That's just the number and your biological age. And that is how, you know, what is really the, call it the age, you know, the level of your cells in terms of how

how good your cells are functioning relative to what, you know, what might be normal from a chronological standpoint on that. And they're different. And we know that when people live healthy lifestyles, and this includes good nutrition, good sleep, controlled stress, exercise, as we all promote, that they're, the biological age is a little much lower relative to the, just a number.

So we never take an absolute number into effect. And people have asked the same about, about Athletica in terms of the prescription. And this is why, like, you know, we've, you know, we've done interviews with some of the world, the physiologist of the world record holders for, in the 70 plus age category. And these guys are doing, you know, 2:48 marathons at age 74 and, you know,

running miles in a ridiculous sub five minute miles kind of thing. Just because of the chronological age, we can't actually say that it actually makes that much of a difference, but the biological age surely does. So, irrespective, this is looking at

how you're individually kind of responding. And then this is probably where a coach really kind of can come into play and assist with helping you to determine where, you know, how things are sort of looking at your biological relativity or chronological age and individualize the training accordingly. Of course, Athletica will be getting better and better at doing these sorts of things, but for now that's about all I can sort of say on the topic.

And I guess because HRV is always individual, you can't like compare to people anyways. But if you've been taking HRV for years, then you can maybe see differences. I don't know.

Yes, well, this is for sure, right? So, you know, look at Mark's data there that we just showed. He's got a whole year of data. And yet that history, that library, is going to get longer and longer. And we are gonna be able to do those sorts of retrospective analyses later on, which should be very helpful in making future decisions. So, yeah, again, we always have the old adage, measure what matters. Well, HRV is one of those...

Mm-hmm.

variables that matters. So that's why we measure it.

several of my athletes are using the Garmin app with a body battery and I've convinced several people to start using HRV4Training . What are some other reliable and accessible methods for athletes to measure their HRV? Are there devices or apps that you would recommend?

Yeah, so I have to probably stick with Marco Altini and who's a colleague and a really a pioneer in this variable. Again, as I've just said, I've stolen all the info from him. That's what I presented at an endurance exchange. But so yeah, HRV4Training is a great one. Another tool is my colleague Jason Moore at EliteHRV, similar principles there.

And these are two apps and both of these use the camera lens to measure your HRV. And we validated that with ECG as well in our lab in New Zealand. So there is, once you get the, once you're comfortable taking the measure, it does become reliable and it's valid. And we've demonstrated that, but also we find the nocturnal measures are also very good. So things like

the data that I just showed you from Mark, that was a, you know, that's taken from the, his Garmin that he wears to sleep every night and just naturally kind of comes in. So it takes a mid-reading and which we call a nocturnal measure of HRV. It takes, it takes an at the average of good readings that it detects across the night.

And Marco has also demonstrated that is a valid procedure as well. And probably the most practical because now you don't even have to do anything. So it's, it's sort of, it's, it might not be as reliable, but it's more practical and practicality often wins out in these sorts of things, right? All you got to do is wear it. Same with like an Oura ring. So an Oura ring. So the Marco is a, an advisor on Oura ring. Last I checked.

So again, many of his principles are input in there. Now, what you do need to be careful on, again, are any sorts of apps that are looking at a single variable. So I'll just, yeah, if you have a device that's looking at a single low variable, that goes against all the principles that we just taught you on this podcast, right? Because a single variable, a single low day,

we just told you is probably irrelevant. You're not getting good help or insight into anything. You need to be looking at the rolling average and relative to the normal range. So that can be a little shocking to some people sometimes because they've been relying on those, but that's, yeah, hopefully that makes sense there, Paul.

Yeah, yeah. It does.

It makes total sense. Because like...

Yeah, I don't want to put any negative twists because there are a lot of very popular apps out there with big names that tend to do that, but they're doing a disservice. And you know this because many athletes will tell you this too. They're like, hey, my X device just told me that I need to take a rest day, but I feel completely fine.

Mm-hmm.

Right, so you, Paul and Marjaana, as coaches, what will you say, right? Yeah, we're training today. Right?

Hahaha

Alright.

Yeah, and like it's just the one, you know, measurement point or one tool that you use to decide what you're going to do. Like if you feel always like you say, Paul, feel always trumps all data. And I've noticed like when I'm training well, the HRV kind of starts dipping down as I'm training and then I realize, okay.

Hmm.

might need to take a day a little bit easier when it really dips down and then I let it come up a little bit. But I have to say, rarely do I ever take a day off unless I'm sick, like this weekend, just because of my HRV is low.

Yeah, it's a tool in the toolbox and that's it. And you pair it alongside those feelings that you just described perfectly in my opinion, Marjaana.

It, yeah.

this.

But I've also done the big mistake of ignoring those dips in HRV. Like my typical range is 8.2 to 8.9 and I was down to 6 when I was over training. And it, yeah, it's just like went down a slope and I just kept ignoring it. Felt horrible, slept bad.

Mm-hmm. Yeah, so they're great. Sure, and it's consistently down, right? So, yeah.

took HRV measurement, why did I take it? Because I didn't pay attention to it. I don't know, but you know, I was stupid. I was a dumb ass, but anyways, is.

Yeah.

No, no, that's so, I mean, again, I'm gonna just quickly share that window because that was the very first thing that we, like when we went on this journey, you have to kind of, you know, we're kind of doing this in reverse, but that was the very first thing that we started doing. So Dan and I were measuring, we're just experimenting this. And Martin, our supervisor, said, why don't you just see if you can get a couple of these elite athletes and see if they'll start taking morning resting HRV for, you know.

And we, and they did, we got two athletes, we got a control athlete up here, and we've got an elite gal here who was taking morning resting values, right? And here again, you see over time, just what you described, Marjaana, where over time that HRV was falling, and then that coincided with clinically, you know, physician.

determined functionally overreaching or overtraining, whatever you want to call it, coupled with shingles. So I mean, that which completely suggests that your immune system is suppressed and the herpes virus comes out as it does with shingles. So that was just like, this was the moment. And this was published, I think it was really early on, in like, 20.

Mmm.

Yeah, like last week, kids have been sick. We have like a head cold in the house. I'm training really well. And when you're training really well, you're always kind of like teetering there on the edge. And then I was looking at my seven day average and I'm like, okay, it's going down. And sure enough, then I wake up with the sore throat and runny nose.

edge.

Yeah, for sure. So it gave you that signal though, didn't it? Yeah.

Um, so it's a.

Yeah, yeah, but it is so hard to know when to stop.

Yeah, it really is.

And that's the art of listening to your body and looking at your life overall. Take that into account when you're doing those training decisions.

So yeah, I think, again, just to lead to that, to lead to this last point, I think, you know, we've been talking about, you know, when your HRV sort of falls, as it did with Marjaana, as it did in many, you know, case studies, etc. What can I do as an athlete or a coach when I'm getting these consistently low readings in my HRV?

suggesting something is off. Okay, so first thing that I can do, low intensity zone two training. Change up the day, use the Workout Wizard move the session, whatever it may be, but change over to more of a zone two kind of stimulus. Almost, that should be the number one tool in your toolbox because we consistently see that is one tool that can help.

raise HRV. So, you know, if you're, if you had a hit session planned, change it to a recovery session or an aerobic, you know, L2 session. Okay, that's, that's principle number one. Sleep. Is there anything you could do about your sleep to get a little bit more? That sleep is a huge tool. When we get better sleep and sleeping more soundly, quality and quantity, HRV tends to rise. We remember the cold water immersion talk that we gave. That is another thing that is,

big surplus in HRV is cold water immersion. That's another thing. Do check on your diet. Diet is another one that really goes into HRV. We saw Mark's data before. We know it has a big influence. And here's one we don't often think about, but it's like social connection. A lot of us are, you know, maybe in this space are a little bit introverted, myself, certainly. And we can spend a little bit too much time isolated with our computers, away from people.

get in with, you know, check on your social contacts and whatnot, because that's actually another thing that raises your HRV is just being around people. It's natural and it's something that's good for us. So I'll just add those points there as well, Paul.

here are the things that I've learned this week that number one, HRV is an emerging training tool that helps us monitor life, stress and health, not just your training stress. And if you pair that with how you're feeling, that's a really good tool. Number two, we're looking for HRV trends in adapting to the training stress as it is.

in as HRV increases, generally that means we're positively adapting to the stress and ready for training. And number three, it's a very individualized response to training session and there's a recovery profile on Athletica that's going to help us measure that context of your HRV and help us understand how we are ready for training on a longer term basis. So

That is all for this week. Thanks for listening and join us next week for the Athletes Compass. You can help us by asking your training questions in the comments below, liking and sharing the podcast and giving us, yes, five star reviews, engaging with us on social media. From Marjaana Rakai and Dr. Paul Larson, I'm Paul Wurlowski and this has been the Athletes Compass podcast.

engaging with us on social media from Marjaana Rakai and Dr. Paul Larson. I'm Paul Warloski and this has been the Athletes Compass.