Karmin continues her series on heart rate variability (HRV) testing. Everyone concerned with pacing - a subject everyone with ME/CFS/FM has reason to be concerned with - will find vital information in Karmin's blogs. Among the highlights:
Heart Rate Variability (HRV) - An Under-Utilized ME/CFS/FM Management Tool: PART II – Surveying the Landscape by Karmin
- Tracking your heart rate is a good idea, but tracking your HRV can provide a deeper, more informative cut particularly with regard to cognitive activities
- As others (Dr. Pocinki, Staci Stevens, Dan Neuffer) have asserted, Karmin's data suggests there's more to the autonomic nervous system problems in ME/CFS/FM that an over-active fight or flight system.
- How to watch out for injurious parasympathetic nervous system spikes.
- How slow improvements with HRV are better than rapid shifts.
- Why exercises like yoga may be better for ME/CFS/FM patients than isometric exercises.
This series of blogs is meant as a beginner’s guide to using Heart Rate Variability (HRV) to manage ME/CFS. In my last blog I explained how HRV measurement can provide a window into the function of the Autonomic Nervous System (ANS) and I detailed how to begin measuring HRV.
See "Your Crash in a Graph: How Heart Rate Variability Testing Could Help You Improve Your Health"
Once familiar with measuring HRV, you can begin using it to survey your ANS landscape. I have found it to be an eye opening experience!
It is important to first think about what data you want to collect.
In my initial enthusiasm for HRV, I was collecting lots of data whilst doing all sorts of activities. All that measuring did give me interesting information, but for the most part it didn't change how I managed my illness. As well - being at the severe end of the ME/CFS spectrum - I felt I needed to get the most value out of my data for the least amount of work.
There were other factors I also considered. There is a tendency in ME/CFS for the ANS to over-respond or over-correct following an activity. For example, when the Parasympathetic Nervous System (PNS) is activated, there is sometimes a reflex Sympathetic Nervous System (SNS) response that follows, and sometimes even further PNS and SNS responses after that. Recording HRV during an activity does not tell me what ultimate effect that activity will have.
- For more on this see Dysfunction Junction by Dr. Alan Pocinki
The Key Data Point - Morning Resting HRV
HRV’s strength is as an indicator of recovery. And it is morning HRV that gives that information. (In my opinion, heart rate monitoring is more suited to monitoring during activity). I, therefore, believe that the most useful HRV data comes from assessing the carryover effect that various activities and treatments have on my next morning HRV numbers. So my focus is on measuring recovery by tracking morning resting HRV. Using HRV in this way brings me huge benefits for a tiny amount of time and effort.
Tracking Everything - the LogsAll App
As mentioned in my last blog, I use the (iOS) LogsAll "Track Anything" app to give me more detailed information from my numbers including: graphs, trends and averages. I track all my HRV measurements: HRV, HF, LF, LF/HF, and HR – as I find it much easier to see the big picture when all are considered together. I enter each of these measurements into LogsAll every morning.
As well as recording those HRV numbers, I record data for various factors that may (or may not) be having an effect on my numbers - such as sleep, rest, supplements and medications. HRV apps are quite limited in their ability to clearly identify the influence on HRV of these factors. But by recording this data in the LogsAll app - instead of vague qualitative assessments obtained from the HRV apps – I accumulate quantitative results for the effect that these factors have on my next morning HRV.
Main page on LogsAll showing some of the factors I am tracking ->
Initially I was recording actual HRV numbers for each factor I was assessing. However I later changed to recording the change in numbers from one day to the next. My reasoning is that I begin collecting data on different factors at different points in time and I don’t want to disadvantage factors that start at a time when my HRV numbers are trending low for prolonged periods of time.
Before you begin recording data, remember that the information you get from HRV tracking can only ever be as good as the data you put in. You therefore need to be vigilant about protecting the integrity of your data. For example: consider the effect of drugs such as beta blockers. I am always careful to take my beta blocker medication at the same times, and I always take my morning HRV readings before I take my morning dose. Also be sure to rotate factors in and out in different combinations.
Don't always test the same treatments together. Always
- take your readings at about the same time each morning
- use a good quality chest strap
- check signal quality in your HRV apps, and
- regularly replace the batteries in your equipment.
To add data - go to the LogsAll main page. Click on ‘Add’ (bottom left of screen), then the factor you are tracking, then add your data. You can also attach a note to any entry - that entry will then be highlighted in green. I use notes to highlight extraordinary factors such as infections or medical appointments.
LogsAll data entry page
Clicking on ‘List’ (bottom centre of screen) provides a list of all results for a particular factor:
LogsAll ‘List’ page for SweetBeat HRV results, with green highlighted entry.
By clicking on ‘Stats’ you can see the statistics for each factor:
LogsAll ‘Stats’ page
Recording each day’s data is not particularly labour intensive, and the value I get out of this morning ritual makes it well worth the effort. Perhaps I’m weird but I actually find it quite a meditative task!
Different activities and treatments have different effects in different people. Keeping quantitative data on them enables me to determine the best treatments for me. For example, I can answer questions such as: Does taking electrolytes increase or decrease my next morning HRV, and by how much on average? I can also test different electrolyte formulations against one another.
To be clear: this testing will never make a perfect scientific experiment, but I find it sufficient for a personal experiment – and far superior to the basic information that HRV apps provide on the effect of various factors. I now have over 1000 days of data recorded. That sort of volume gives my data a good amount of weight.
LogsAll can be used to assess treatments in other ways. For example, green markers (added by writing notes in the data entry page) can be placed on graphs at the beginning and end of new treatments.
LogsAll graph showing adverse effect of Cholestyramine (CSM) on my weekly average HRV
- First green dot is first reading after starting CSM
- Last green dot is first reading after ceasing CSM
I am going to detour for a moment here to explain that HRV tracking is not as simple as: high numbers = good, low numbers = bad.
Occasionally (but quite regularly for me) my HRV numbers throw up a surprise – a sudden big increase in my numbers – in particular the HF (High Frequency) result. (Remember from my first Blog: HF is considered to be a measure of parasympathetic function). Your HF graph might look something like this:
LogsAll graph of SweetBeat daily HF scores showing a sudden big increase in HF
You get excited and start to think you’ve had a big improvement - all your treatments are starting to help! But unfortunately this sort of rise is not a good sign. To make this point even clearer, this is what happened in the few days after the above spike:
LogsAll graph of SweetBeat daily HF scores showing the very low HF numbers which followed the spike
It can be helpful to look at HF spikes from the point of view of balance. This is one reason I like the dial graphic in the Elite app - if we go too far to the left (sympathetic) side we go into the red danger zone, but we do the same when we go too far to the right (parasympathetic) side.
HF (parasympathetic) spike as depicted in Elite app
The low readiness score of 3 reflects the need to rest ->
For me, HF spikes commonly occur at the beginning of an infection, but also can occur after prolonged overdoing, or pushing parasympathetic treatments too hard.
The parasympathetic nervous system acts as a brake. The HF spike is a sign that you have depleted your reserves and your body has put itself into recovery mode. I consider HF spikes a red flag warning to stop, and rest until I am back to normal.
HF spikes can be deceptive because they often make me feel wired or like I have a bit of (borrowed) energy in my body. It is only when I come out of the spike that I feel my energy crash. (In fact, I have wondered whether so-called delayed crashes may only seem delayed because of a HF spike occurring immediately before.)
HRV tracking will enable you to see these spikes for what they are, and not fall into the trap of spending energy you can ill afford to spend.
If you take one thing away from this blog, it should be the importance of identifying HF spikes. When you can identify these spikes via HRV tracking, you will see them for what they are – a sign that you really need rest.
Note: It is important to think about your data when in a parasympathetic spike. The high HF numbers that occur during a spike are not good. I don’t want to contaminate my data by including those big numbers in my calculations of what treatments help most. I remove (or separately record) data taken during spikes – so that I am always comparing apples to apples.
Assessing Morning HRV Numbers
When you begin HRV tracking you will probably want to know how your numbers compare to normal values for the general population, but this is not really important. You have ME/CFS so your numbers will almost certainly be low. The important thing is how your HRV numbers compare to your normal numbers. However the table below from Elite HRV can provide some insight into ‘normal’ HRV scores:
Elite HRV norms (relevant to the Elite algorithm only)
Calculated from data from 10,308 Elite HRV app users
In order to derive meaning from your own numbers you first need to establish a baseline – to determine what your ‘normal’ is. It is important to begin during a relatively stable period. If you begin recording during a dip or spike the numbers you get will not be indicative of your true ‘normal’. After as little as a week of recording you will have a reasonable baseline to start working with.
The automated interpretation provided by HRV apps can be very helpful but I feel it is important to also learn to make interpretations yourself - because the apps won’t always get it right. (I do find Elite better than SweetBeat at detecting bad days – especially in detecting parasympathetic spikes).
SweetBeat’s automated data interpretation
Results should always be put into personal context: how much stress is in your life, how well are you pacing, how is your perceived energy level? You must look at everything together. That's one reason an app will always struggle to give a perfect interpretation every day. And why you should make the effort to learn to interpret your numbers yourself.
You cannot consider numbers in isolation. A reading of 35 means nothing on its own. But a reading of 35 when your baseline is 25 or 42 does have meaning. Look at your daily HRV number and how it compares to your baseline. Is there any significant change – either up or down? In the Elite app, as well as a baseline number, you are given a weekly and monthly average. This makes it easy to see if your daily result is higher or lower than your baseline or longer term average.
Elite readiness page: although my HRV score (33) was worse than the previous day (38), it was the same as my baseline (33), the same as my monthly average (33), and therefore normal for me. ->
It was therefore a good day, with a readiness of 10, despite the apparent drop in HRV score.
If your number is significantly higher than normal, keep in mind that genuine increases in HRV usually take the form of a slow gradual upward trend. If your HRV is suddenly very high – you need to ask yourself if it is a parasympathetic spike. Spikes are easy to pick when you look at all your numbers together. For me, parasympathetic spikes tend to have some or all of the following characteristics:
Next consider your sympathetic/parasympathetic balance (LF/HF). SweetBeat gives numerical values for LF/HF, whereas Elite gives only a sympathetic/parasympathetic dial. SweetBeat considers a result of around 2:1 as normal (but I rarely manage anything like that first thing in the morning). Elite indicates balance via a centre ‘green’ position on their dial (as in the diagram above).
- Sudden big increase in HF
- Sudden big increase HRV
- Sudden big decrease in HR
- Sudden big decrease in LF/HF
<- SweetBeat shows sympathetic/parasympathetic balance as an LF/HF numerical value in the top right of their ‘geek’ screen. This result of 12.8 is said to indicate sympathetic dominance.
Assessing Contributory Factors
Assessing contributory factors is not essential to HRV tracking. It is just an add-on that I find extremely helpful. You could leave this out of your tracking plan. Or alternatively try tracking a few factors to see how helpful you find it, and add further factor experiments in as you see fit.
When you see positive or negative changes in your daily HRV scores, think about what factors may have contributed to those changes – it can be literally anything: physical activity, sleep, food, visitors, temperature, infection, stress. Often it will be obvious, but often all you can do is hypothesise. Further complicating the process is the fact that your numbers represent the total effect of all contributory factors together.
Begin keeping LogsAll data on the factors - both positive and negative - that you hypothesise may be relevant. The aim is to gradually tease out the effect of each individual factor. With time and increasing data, you will be able to determine with more accuracy what helps and what hinders, and to what degree. By identifying the factors behind adverse changes, we can take corrective actions on a day to day basis to prevent major problems. It is like an early warning system.
When you see adverse changes occurring, take rest day(s) without guilt. Get back to basics. Look after your body with good sleep, diet, hydration and rest. Reducing negative influences on HRV may actually have a greater impact than increasing positive influences. We’re often most keen to add a supplement or add an activity to ‘take away’ the problem, but it may be even more important to identify and remove the negatives.
Once you accumulated sufficient data, you will begin to see which contributory factors help/hinder which numbers. You can use this information to plan your day. For example, if my LF/HF is higher than normal on a particular day, I know which factors to include or remove that day in order to bring it back down by the following day.
Having now recorded over 1000 days of data, I find my data an absolute goldmine of information. It is hard for me now to imagine trying to manage my illness without it. To me it makes no sense at all to be flying blind – guessing what is happening in my ANS, and why. I will go into this tracking of individual factors in greater detail in my next blog.
As well as assessing daily results, it is important to watch your longer term trends. In many ways they are more important than day to day fluctuations - particularly for identifying the long term sustainability of your general level of activity. You can use weekly, monthly, or rolling HRV averages for this. These averages remove much of the day-to-day fluctuation of HRV scores and make your overall trends clearer.
What you are aiming for is a slow gentle upward trend, or perhaps more realistically, a stable, level trend line with no downward trend. If you are trending down over time, you’ll need to reassess your level of activity. (When assessing trend lines, keep in mind that parasympathetic spikes will tend to give trend lines an artificial boost).
When I first began HRV tracking, I discovered from my trend lines that my day-to-day level of activity was too high. It was a rude but necessary awakening. I still sometimes struggle to oblige my numbers (life often gets in the way!) but my HRV tracking does make me more accountable, and makes the effects of bad choices more visible and tangible.
Clear downward trend in Elite 7 day average HRV (green line)
Elite monthly averages plotted in LogsAll
LogsAll can provide trend lines for your daily scores. This to help you make sense of the maze of your daily scores which are often scattered high and low.
The last 12 months have presented me with some challenges which made obliging my HRV numbers difficult. The result has been a downward trend. LogsAll can make these long term trends clear via their trend lines feature (activated via a drop down menu)Regardless of the fact that your Doctor may have limited knowledge or experience of HRV tracking, I believe graphs such as the examples in this blog can be used to give your Doctor valuable information about your progress. Hopefully in the future this sort of information will be more commonly monitored in the management of ME/CFS patients.
New ME/CFS HRV Research
I am very pleased to see that New York Psychologist and IACFSME President Dr. Fred Friedberg is now undertaking a study which hopes to ultimately see ME/CFS patients using HRV tracking to manage their activity levels.
Find out how to participate below:
We have the tools for this now – no need to wait!
I find that one big advantage that HRV monitoring has over Heart Rate monitoring is that for me it better identifies problems with non-physical overdoing. My heart rate is not usually adversely affected by cognitive exertion but the adverse effects do show up in my next morning HRV. A useful tool!
Graded Exercise Therapy (GET)
I believe HRV monitoring may be a great defense against PACE-style Graded Exercise Therapy (GET) - or at least a way of determining whether GET is helping or harming a particular patient. Trying to argue that a patient should continue a particular GET programme when their HRV numbers are clearly being adversely affected surely leaves a GET proponent without a leg to stand on. I only wish I had known about HRV tracking when I was prescribed GET years ago!
I have always felt there was something different about yoga that makes it more tolerable (and beneficial) to ME/CFS patients. It feels like I am working with my body, not against it. Yoga was the last exercise I was able to do as I slid down to becoming bedridden, and it has been the first exercise I have been able to add back in.
At the beginning of this Blog, I explained that I no longer monitor HRV during activities, but rather use morning HRV as my foundation for determining an appropriate and sustainable level of daily activity. However, to finish, I am going to share the results of an interesting experiment I did some years ago, during an exercise activity.
I divided a very short exercise session into two halves. In the first half I did a low level lying yoga pose, then in the second half I did a low level lying isometric type exercise of similar difficulty. I was blown away by the resultant graph:
SweetBeat graph: First half showing sympathetic/parasympathetic balance whilst doing low level yoga, second half showing sympathetic activation whilst doing a low level isometric exercise - >
Despite the fact that my heart rate was well within the anaerobic threshold during both exercises, the graph shows how much more the isometric exercise activated my sympathetic nervous system. Any wonder it feels like there’s something different about yoga!
Importantly, not only does yoga give better autonomic balance during the activity, but for me the positive effects also carry over to the next day – as evidenced by improved next morning HF (parasympathetic) numbers.
I find this graph especially interesting in light of Georgetown University research showing that increased SNS activation with exercise can temporarily cause POTS
Heart Rate Monitors
Many heart rate monitors are available.
- Karmin uses the Wahoo TICKR Heart Rate Monitor for iPhone & Android which has center front clasp which makes it much easier for someone with ME/CFS to put on!
- The Polar H7 Bluetooth Heart Rate Sensor and Fitness Tracker has been considered the gold standard but her frame was too small.
Part I: Check out Part ! - "Your Crash in a Graph: How Heart Rate Variability Testing Could Help You Improve Your Health" - of Karmin's HRV blog series for ME/CFS and FM for the basics of HRV testing and the apps she uses:
Pacing and Activity Management - See Health Rising's Pacing, Exercise and Activity Management Resource Section
Heart Rate Variability (HRV) An Underused ME/CFS/FM Management Tool: PT II – Surveying the Landscape
Part II of Karmin's blog series demonstrating how to use HRV readings to manage your health