What logic? Please explain.
Don’t look at HRV alone. Always look at rHR and HRV together and look at trends over short, medium and long time periods.
If you look at HRV as a stand-alone number, it isn’t going to give you any usable information. A too high HRV can be worse then a low HRV.
It’s a complicated metric…
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You would have to look at rhr, coefficient of variation, you have the sDNN metric that tells you how your body is handling stress, then you would have to look at which system predominance you have more active, not always a high rMSSD means it is better, you have to create a confidence interval of both rhr and rmssd and from there together with your sensations make decisions, it takes a lot of practice and seeing a lot of data and personal behaviours to be able to interpret correctly.
As others have said, it’s important to look at other metrics and trends, not just HRV, to paint a more complete picture. But, in short, if everything else is in order and if the intensity was appropriate without being overtaxing, the body will try to adapt to the load. I’ve seen the effect you describe in myself—a combination of aerobic & solid tempo led to increased HRV, lower rHR and increased EF. The key is to know how much, when and how long to ride that wave… 'cause of you try to take it to the shore you risk shore break.
HRV indicates health of the nervous system and thus system readiness. An appropriate kick provides stimulus and relaxation—the body and mind are energised and can use that energy to clean house and feel good about it. But too much and things get messy.
I don’t just stick to one piece of information, apart from the athlete’s perceptions, I look at the predominance, sleep time and now we are testing with BodyBattery from Garmin to see if the quality of sleep corresponds to the BB charge rate. You can have a high HRV and have a different predominance.
Thanks everybody for your answers
Here is my chart of “HRV”
As you can see, in violet here is the charge of training, and the day after, instead of decrease like it would be the “logic”, my HRV rMSSD (green rod) increase in most of cases. If my body is tired by the training, the parasympathetic system would take the lead so my HRV “must” decrease no ?
I’m sorry if it’s not clear and if my explanation are not good/clear (and also my english), i’m a beginner in running and on Interval.icu
Thanks again everybody
You need to look beyond the 24 hour effect. You have 7d, 60d and CV in an HRV graph. Do you also have a graph showing daily, 7d, 60d for rHR??? What about sleep and overall loading trends. And what about life stress? And for those harder sessions, are they tempo or longer lower-intensity sessions, or very short high intensity, or some mix? These are the other factors that need to be considered. If you ‘charge’ the body appropriately and if conditions in the body and life allow for absorption of the load, then the body and mental well-being will continue to improve (for a time). HRV can continue to increase if the body is loaded appropriately and provided necessary environment and time to recover from that load. To presume that HRV will always decline secondary to an increased load is to miss the point.
You can’t rely solely on the rMSSD value, it’s a mistake and scheduling training on that alone is not the best option. Why don’t you compare more metrics, what has happened to your RHR, how are you coping with the physiological stress of training, how are you coping with the physiological stress of training? All of this needs to be assessed to make the right decisions. Everyone thinks that if the pulse rate drops it is a good sign, if it drops sharply, it is not a good sign, if the tendency is to go down gradually it is a good sign, what is your level of athlete? You could use the lnrMSSD and use “safety” ranges of 1 SD if the level is amateur, 0.5 SD elite and 0.2 SD professional. After this I tell you why you have had a high HRV, simply your parasympathetic system is active not as a signal of preparation but as a signal of trying to recover from a previous effort.
My advice is to not just look at one value and look at the other markers available and the most important thing that many people forget: Personal Perceptions.
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I don’t usually share my data, but I’ll do so in this case for the purpose of illustrating one way to think about the multi-factorial process of evaluating training. I’ve labelled the large screenshot below with the following discussion points. (Open it in a new tab and zoom in.)
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In the entire screenshot, this is the point that may first catch one’s eye. Form appears to be high risk. I say ‘appears’ because looking only at it provides no context. Let’s look back at the weeks leading to this point.
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This is the point when I finally had three green lights for training this year—physical, mental and life structure. I’d been working out so I wasn’t exactly getting off the couch. The winter had lots of alpine skiing and skimo but that did nothing for swim, bike, run other than provide a solid aerobic base to build on.
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There’s a three week build that’s bike dominant (Wkly Hrs SBR graph). The body is clearly having to work as is seen by the red in the HR and Power graphs. As volume increases the percentage of intensity decreases. HRV and rHR appear stable until the start of week three when rHR begins to dip. This may be a reflection of improving fitness, but more info is needed. There is a slight uptick in EF but the real standout is Mood. I’m feeling good. Still, the red Form tells me that I ought to back it down a bit. I also know, historically, that after three weeks of loading I’m usually ready for a week or two of maintenance (lowered yet steady loading).
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Sure enough, Subjective Fatigue and Soreness level out during those two weeks. So does Form. Mood is still good. Time to start an easy ramp again.
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My Sleep and HRV device died so no data was collected during this period while I wait for a replacement.
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Mood is a bit wonky in the initial running volume build. (See Wkly HRs—SBR graph.) I’m going easy with it so I’m not worried about any kind of risk with running. There was a lot going on mentally and emotionally in life that affected Mood. I toss in some long hours of outside labour to help support mental wellbeing.
_1. Bingo. The time outside working directly with nature does the trick. I feel great but Mood, Fatigue and Soreness are still kind of all over the place. The volume has been mostly very low intensity so I’m not overly concerned. Mood is fluctuating but on the high end. EF is increasing wonderfully. Still, all that volume has pushed Form deep into the red; this needs to be respected.
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This is when I notice a big red flag. HRV is above SD and rHR is below SD— Parasympathetic Hyperactivity. Normally, we think of high HRV and low rHR as a good thing but when they are acutely that way and in combination with each other it’s not good. The focus to boost mood has worked; I feel great but my PNS was given a turbo charge that the other systems aren’t strong enough to maintain. PNS is overreaching and on the verge of burnout. I’ve seen this before and it requires immediate correction or I’m going to crash hard.
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Course correction with zero intensity—just moving my body in nature. This soothes the PNS—HRV and rHR stabilise at a much improved levels than point #2 discussed earlier. This is a good sign.
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Slightly increased volume and intensity load causes Form to dip. It feels good to be working again tho. HRV is dropping, however, which could be an after effect of what was going on during the previous weeks, or it could be a sign that the body is a bit tired. Mood is low, which in combination with lower Form and higher Subjective Fatigue and Soreness say that it’s time to back off again. It was a pretty speedy ramp going into point #1. It’s clearly still having an effect on the system.
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Low intensity volume for a couple of weeks. I maintained a tiny bit of Z3 and Z4 work to stimulate the neural pathways. HRV is climbing thanks to the stimulation and to some really excellent fun with friends at Cykelvasa in Mora (look it up) and low intensity to help with training absorption. Fatigue and Soreness are decreasing. rHR is stable. Green lights again, which is not to say that I have the ok to hammer myself. Think longterm.
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I feel good. Sleep hasn’t been super great the past few weeks but that’s a function of how my muscles respond to all the strength work. (I won’t unpack this. It’s something that’s been a pattern for 45 years.) Mood is stellar. I want to push and let myself. Upper body is responding well to the swim focus. Overall, it’s a bit too much intensity but I know that the following week is going to be a maintenance week—conscious overreaching.
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Next week will be long days outside with carpentry work. I’ll try and get one easy training session every day just to keep in touch with all the disciplines (swim, bike, run or walk). After that, assuming green lights, the following week I can move back to consistent workload with low intensity and increased bike volume. I copied and pasted this week’s plan into that week just for reference. It’ll get adjusted.
Edit to add Additional Thoughts
Polar has Readiness and ANS scores that are based on HRV, rHR and Sleep quality and quantity. I don’t put a lot of value in them but it’s interesting to look at and ask myself why Polar thinks that my system is in a certain condition or not. If there’s an outlying number I dig deeper. Mostly, these numbers are acute reflections of something that happened in the preceding 12-48 hours. This information helps me modify (improve) lifestyle and training behaviour. I rarely use the information to inform increasing loading but will consider them for decreasing loading.
Polar also tracks Body Temperature. I’d love to graph it but currently Intervals.icu doesn’t pull this data from Polar. It’s probably something I could get via API but I don’t script and I’m not going to learn it. That’s what I have Intervals.icu for (so that I can spend my time elsewhere, i.e. meditation, journalling, contemplation, silence. 
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The Motivation, Mood, Subjective Fatigue, Soreness and Stress metrics are daily entries on my part because I know they have a huge roll in my training and well-being.
I also record Alcohol intake and Injury.
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Really insightful. Thanks a lot for sharing, you clearly have a good understanding of how this ‘can’ all fit together and provide extremely valuable information.
Your level of analysis, however, can’t be reached by everyone. Let’s hope the tools we get in the future will make such analysis gradually easier for the ‘average’ guy.
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Thanks mate.
There are people in this forum, like yourself, who have a far grander handle on the nitty-gritties than I do. My strength lies in problem solving. I look for details, ways to connect dots and every opportunity not to jump to conclusions. There’s always something more subtle.
A better way to look at it is with the lnrMSSD, we avoid high outliers, 1 SD would apply for amateurs, 0.5 for better prepared athletes and 0.2 SD for professionals, that would be the desired SWC, as shown in many papers.
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Thank you for your answers, they’re really interesting. I’m going to try to learn as much as I can from them in order to increase my knowledge and improve my data analysis as well as my knowledge of my body, although some of the concepts seem very complex and I don’t know anything about them (or even the terms, such as lnrMSSD, PNS…).
To summarise your answers to my initial question and to check that I’ve understood what you’ve said, I’d say that HRV varies according to a huge number of factors and that only a cross-analysis of as many of them as possible can provide a correct analysis. You need to collect as much data as possible (stress, motivation, training load, type of training, sleep, etc.) in order to use the graphs correctly.
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Yes, and…
HRV does vary according to a number of factors. It also just varies and change over time by way of season and age. Many of the items I listed will affect the Parasympathetic Nervous System (PNS—rest and digest) and Sympathetic Nervous System (SNS—fight or flight). And there’s more, i.e. microbiome, thus nutrition. Try not to get caught up in thinking that HRV is the primary factor upon which all these things affect and from which we make major decisions. Everything is constantly affecting everything else.
HRV is just one factor amongst many from which we can draw information to help develop a picture. This picture has acute, short-term aspects as well as chronic, or long-term patterns. In medicine we say that one set of vital signs might not say too much, but a series of them tells a story. The same is thing is true with well-being and fitness. Watch for patterns and outliers to those patterns. It might seem a bit daunting at first with all the things that one could look at. Don’t believe any “should’s”. Just pick a few things, get to know them a bit then add the others along the way.
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There’s an easy metric you can track every session that provides some depth to your daily and trending HRV—HR during a session.
If HR is blunted (lower than) what you’d expect for a given RPE and power or pace, it may indicate that PNS is struggling. In my example above I said that I was consciously overreaching at the end of last week. My thinking was that I had a planned maintenance week starting in two days (an easy day and a full rest day). During my trainer ride on Friday, HR was blunted during warmup and throughout the bulk of the session. It was only a few beats lower than expected but it was distinct. Had HR been only a couple beats even lower I’d have switched immediately to a very low intensity session to support oxygenation and waste clearing without adding load. I knew I was on the edge given the various information that I laid out in my explanation. As it turned out, the work I did was, in fact, too much; The following day became a full rest day not an easy day. Then yesterday (Sunday) was a long day outside with friends at the barn doing easy movement setting up for the week of carpentry. I’m as prone to pushing too hard as much as anyone. 
Dehydration and acute & chronic body temperature deviations are two more factors than affect the body systems.
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I have a question about all your graphics :
How do you choose the right data for the graph you want to obtain? Does this come from your “anatomical”/“medical” knowledge?
For example, for the rHR graph, how do you know that the base should be a 7d moving average? Similarly, what form of calculation have you chosen for the red line (rHR)?
I’m just trying to understand how to create graphs that are relevant for later analysis.
The 7 day moving average + 30d baseline is standard and derived from hours and hours of number crunching by leading experts in the field. There is nothing to say you have to stick with these standards but they probably are correct for the majority of people.
Check out Marco Altini for more info https://www.marcoaltini.com/
Also search for posts in this forum from @Luisma_Gallego_Soy_P - He is also an expert with years of study in this field.
This thread might also prove useful
HRV-Guided Training
For the graphs:
Go to fitness tab. Search for charts (magnifying glass). Search for rHR and you’ll find a list of existing custom charts.
In my graph below it’s a normalised band of moving 30d average +/- 1 SD and the baseline is a rolling 7d average
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Your question is several in one. The first item is, the ‘right’ data is that which is pertinent to you. If you don’t need the information, or if it detracts from your own effective training then it’s not right for you. The second item, and the one that I suspect you’re primarily interested in is, how do I know what’s ‘right’ for me? IOW, what is useful information? The next few items are, where and how do I learn about all the possible items so that I can determine what’s important for me and what it all means and fits together.
By starting this thread and asking the exact questions you are asking is part of the path. There’s a ton of information in the Intervals.icu forums. I suggest that you don’t try to get a handle on it all at once. It takes time. There are people like who know details that I have trouble grasping. And there are metrics that seem like cool bits of information but that confuse me or just don’t fit into my decision tree.
For me, I’ve gathered the metrics, created charts or modified others’ charts over time. Yes, it’s based on my knowledge and experience gathered from schooling, work, training, experience, learning from others, etc. I can be pretty nerdy in my own way but I like to try and simplify the product while giving multi-dimensional perspective. Personally, I’d suggest that the graphs I have shown are the most common items to keep an eye on. There will of course be differing opinions for various reasons. Some of the items I track, i.e. subjective values, are known to influence health and fitness but not everyone has learned to feel into themselves, or perhaps doesn’t currently feel them to be important for themselves, to easily make status judgements about mind, body, spirit.
@nasatt has given directions for how to find graphs. I’ll share my graphs as well so that you can find them. There’s no sense reinventing the wheel; just tweak them to your needs and visual desires.
Regarding the maths for what averages and standard deviations, I credit @MedTechCD for combing the literature and providing information in this thread, HRV-Guided Training - #559 by Howie.
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I still think that the best option is lnrMSSD and use desired ranges (SWC) of 1 SD, 0.5 SD and 0.2 SD depending on the level, the lnrmssd provides a range easier to understand and compare, then you can create those desired ranges depending on the level of the athlete, @david if you see that you can implement the system I leave you the paper of Alejandro Javaloyes who did the study with very good results.
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I took some time to see if the log transformed rMSSD gives similar results as the raw rMSSD. There’s no difference for daily values, baseline and normal range. But the absolute value of the CV% is impacted significantly, and that can be important.
I created a new Wellness field to register the 20 x Ln(rMSSD) and use that for the HRV Fitness chart now. I’m populating that field from the script that I run for all my wellness fields. You could create a similar field and ask @Inigo_Tolosa to populate it like he does for the Training Advice field. He just needs to add a line to the MatLab code that sends 20 x Ln(rMSSD) to that new Wellness field.
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