Category Archives: Heart Rate Variability

GABA Dabba No Can Do

I conducted a straightforward test of a supplement that claims to help calm the nervous system. I had high expectations because I had read about the effectiveness of Gaba receptor inhibition but I found that Gaba Dabba no can do.

Gaba Dabba No Can Do

The supplement I used was Gaba Calm by Serene Science. The “calm” on the label seemed a good start. This product can be found on the web for about $20.

The site selling the supplement says, “GABA Calm combines two of the main inhibitory neurotransmitters, GABA and glycine, with N-acetyl L-tyrosine, which is a precursor to the neurotransmitters dopamine and norepinephrine. In addition, taurine supports the calming effects of GABA.”

Reviews were mostly positive.  People claimed it worked well or that it had a mild and pleasant effect.

My Question

Would taking GABA increase my morning heart rate variability?

What I Did

I used morning heart rate variability as the measure of calmness. For 21 sessions, based on a randomly generated instruction, I either took GABA Calm or did not. Afterwards, I measured and recorded my heart rate variability (rMSSD). I then compared the effect on my heart rate variability for the two conditions to see if taking GABA changes my heart rate variability or not.

How I Did It

I generated a column of 35 random numbers that were either a “0” or “1.” These would serve as my instructions and control. When I was to determine whether I was to take GABA Calm or not I would consult the sheet. If the next unused number was “0” I did not take GABA Calm at 6:30am. If it was “1” I would take the supplement. Once I completed the session I would put the date next to the number used to show I had used that number.

At approximately 7:00am I used Heartmath EMWave Pro to measure my two-minute heart rate variabilty. During the reading, I used a paced breathing app to ensure my breath rate was similar in each reading. On the spreadsheet, I would record my rMSSD along with the date.

I conducted 21 sessions. When completed I sorted the spreadsheet results into two sets. I then compared them looking at their average and using a Student’s TTest.

What I Learned

The GABA Calm supplement had no impact on my morning heart rate variability. The averages for the two states were close and the p value for the TTest showed that the results may have well been random. A significant result is p under .05. The metrics:

Avg With GABA 62.1
Avg Without GABA 60.7
p TTEST 0.850

This study shows that GABA Calm does not increase heart rate variability 30 minutes after taking it. I use heart rate variability as a proxy for calm because if variability is high, the system is at rest or not stressed. The “calm” is profound enough that your breath raises and lowers your heart rate. If the body is in any state of excitement the variability goes down.

It is likely that the supplement makers at Serene Science would propose a different measure for stress. In their video stress occurs when we feel moody or worrisome. They claim their theanine product allows you to tap into your own calming chemistries. The instructions on the bottle say to take it 3 times a day, forever. That comes out to approximately $20 per month. How you measure the results is unclear other than you might feel less moody.

I am not a fan of taking a supplement forever to hypthetically feel less moody. The approach feels like “treating” for moodiness to create a revenue stream. That said, the idea of targetting a mood state with a single dose is also somewhat artificial. Either way, targeting heart rate variability with GABA Calm is likely not how it was intended to be sold, nor does it work.

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Meditate Better by Leaning Your Head Back

I had started using Heartmath again after hearing a great podcast by Damien Blankensopp on paced breathing and its positive effects on the autonomic nervous system. As a result, I had started doing paced breathing sessions each morning for 20 minutes. That morning ritual provided a great source of data for experiments on how to meditate better.

My friend Dr. Keppen Laszlo is a chiropractor and I mentioned to him my work with heart rate variability (HRV). He suggested I could improve my HRV by leaning my head back during my measurement session. As he explained it to me, this head position relieves negative pressure on the nerves that are connected to respiration.

If following this advice led to more stable respiration and respiration is the foundation for increasing HRV, it would be possible to capture the improvement during my Heartmath sessions. I decided it was worth investigating.
Meditate Better

My Question

Would leaning my head back while doing paced breathing meditation increase my Heartmath scores?

What I Did

Each morning I do a paced breathing session for twenty minutes during which I measure my heart rate variability using Heartmath. A paced breathing session means that I breath use an app to ensure I breathe in for seven seconds and out for seven seconds during each respiratory cycle.

For twenty-one sessions, during each session, I either leaned my head back at an approximately thirty degree angle from the verticle or leaned it slightly forward based on a randomly generated instruction. I measured the differences in outcomes of these two head positions by comparing the resulting Heartmath scores.

How I Did It

During the paced breathing sessions I used Heartmath EMWave Pro to measure a score based on the resonance between my respiratory rate and my heart rate. Heartmath gives a score for the amount of time the heart rate frequency is near .1 Hz. When the meditation is more focussed this “meditators peak” is more pronounced.

At the end of each session, I divided the total Heartmath points generated during the entire session by the exact number of minutes and seconds yielding a Points/Minute score. Some sessions were a few seconds longer than 20 minutes and I wanted a precise comparison.

Prior to the twenty-one sessions, I generated a “0” or “1” randomly in a spreadsheet for each day of the study. On the days that a “0” was generated I leaned my head slightly forward during the session. On the days a “1” was generated I leaned my head back during the session.

When the twenty-one days was complete I separated the head forward and head back data into two sets that I then compared using a Student’s TTest. I also looked at and compared the averages.

What I Learned

Leaning my head back during meditation significantly improved my Heartmath measured meditation scores versus leaning my head forward.  Here are the averages for the two data sets:

Meditate Better

The TTest p value was = .0337. Anything less that .05 is a statistically significant result. There was a clear advantage to leaning my head back during the paced breathing meditation.

I was struck at how conventional wisdom on the standard meditation posture could create a misunderstanding.

Meditate Better

If the novice meditator tries to create an upright posture by pushing the back of the head up (at red arrow) the net effect would be the head leaning forward. This would reduce the ability to keep the respiration stable and have the reverse effect of what is desired in the meditation.

If you are a meditator looking to improve your practice, consider your head position. While keeping your back and torso upright relax the neck and ensure you are not leaning forward. This will stabilize your respiration and the positive from this will be more time in meditators peak and a more robust autonomic nervous system.

Slow Breathing Workout Increases My HRV

What is the Slow Breathing Workout?

I heard Richard Gervitz talking about a slow breathing workout as part of a daily discipline on the Quantified Body Podcast. I had started doing slow breathing sessions back in May 2014 though I had never specifically looked at the effect on my daily heart rate variability (HRV) reading. And I had fallen out of the habit so I was interested in trying it again.

slow breathing workout

A slow breathing workout means taking your respiration to a slower pace than normal with inhalations and exhalations of equal length. This is not normal breathing as it synchronizes the cardiac and respiratory systems. Gervitz recommended 20 minutes per day.

The beneficial effects of doing this breathing include a more flexible autonomic nervous system, increased resilience to physical or psychological stress, and sharpened mental clarity. Motivated by what I heard on the podcast, I decided to jump back into a disciplined slow breathing workout.

My Question

Could doing 20 minutes a day of deep, meditative breathing in the afternoon improve my morning HRV readings?

What I Did

I had a standing practice of measuring my HRV for five minutes on waking each morning. This provided a baseline of 24 readings. I began doing 20 minutes of evenly paced breathing each afternoon. This provided 18 additional morning readings that were impacted by the slow breathing workouts. I controlled for confounders by removing readings where circumstances were out of the norm like low amounts of sleep or too much food.

How I Did It

For my morning readings, I used Marco Altini’s Heart Rate Variability Logger to take a five-minute rMSSD reading.

slow breathing workout

Prior to the five minute readings I would listen to 10 minutes of soft music to settle in and ensure I was relaxed. For my afternoon HRV breathing workouts, I used a basic breath pacer app for iOS. With it, I could set the number of seconds per inhalation and exhalation. This would allow me to breath slowly and at a steady pace for the sessions.

slow breathing workout

I also like to get biofeedback as I do my slow breathing, so I used Heartmath Pro to track how effectively I got I aligned my cardiac and respiratory systems. The Heartmath dashboard shows the HRV in the top panel and the heart beat frequencies in the lower left panel.

slow breathing workout

The useful thing about the biofeedback is that I could adjust the length of my inhalations and exhalations until I found the highest level of alignment. Without feedback I would have to use levels derived from published data. With the biofeedback I had set up slow breathing exercises tailored for my physiology.

What I Learned

Starting an afternoon slow breathing workout regime increased my average morning HRV readings to a significant degree. You can see the lift in the scores on the graph of readings through the period:

slow breathing workout

Looking at my readings pre-program my rMSSD averaged 42.8 for the morning session and post-program it averaged 54.8, a 28% increase. Doing a TTest comparing the readings before and after being on the slow breathing workout showed a p-value of .037, meaning the change was statistically significant. You can see the raw data that is the basis of the calculations.

I found my optimal breathing came out at 7 seconds for each inhale and 7 seconds for each exhale. I started with 5.5 seconds per inhale and exhale and kept moving it up until I found my level.

That said, the biofeedback application is not necessary to get the benefit of a slow breathing workout. Though it is helpful to get the biofeedback readings, a simple breathing app with 20 minutes of practice each day will give you all the benefits. And I will continue with it now that I have established its value.

Booze, HRV and Muse

I’ve become interested in finding with greater precision how my body reacts in different circumstances. I had a story that I felt poorly after eating cheese. It was based on one period of my life and was entirely anecdotal. As I described in my post about my shift to a ketogenic diet, I had started eating more fats, to include cheese. And I felt great. This got me thinking about how many of these unexamined stories guide my behavior.

With that in mind I started looking at alcohol’s effect on waking mental calm and heart rate variability (HRV). I like a glass of wine or two in the evening. It is well documented that alcohol has a physiological impact. From quantified selfers looking at their Basis data to scientific studies there is a wealth of information on the physiological impact of alcohol. My question is how much can my body tolerate before it reduces my heart rate variability and mental calm.

Booze, HRV and Muse

My Question

What impact does having alcohol (or not) have on my morning HRV and mental calm?

What I Did

For thirty-three days on waking I measured my mental calm and heart rate variability while noting if I had had alcohol the night prior.

How I Did It

I would measure my mental calm using Muse EEG headset and my HRV using a Polar H7 heart rate belt that sent data to an app called the Heart Rate Variability Logger. All data went into a Google spreadsheet.

What I Learned

Drinking alcohol the night prior reduced average HRV and increased average Muse “% calm” score. After a night of boozing I was mentally more Zen but my nervous system was under increased load.

The Muse % calm readings were not visibly different between having had alcohol or not. The Pearson correlation (.12%) showed a negligible relationship between the calm readings and whether I had consumed alcohol the night prior.


Booze, HRV and Muse Booze, HRV and Muse


My average % calm after having no alcohol was 36.4% and after having alcohol was 42.7%. Looking at the averages I appeared more calm after drinking. Because the scores did not correlate with consumption we can’t draw any real connection.

My HRV did correlate with consumption, with a Pearson correlation = -.306, a moderate negative relationship. There seems to be a connection with drinking alcohol and a lowered HRV was lower the following morning.

Booze, HRV and MuseBooze, HRV and Muse


My average rMSSD the morning after a night of alcohol was 48.6. A morning after no alcohol the average was 62.1. A moderate correlation and a much lower average verified that HRV seemed to be impacted by alcohol.

But knowing that does not really give me any precision nor any guidance on how to change behavior. So my next study is to examine how much alcohol I can consume and not have my HRV drop. If I am going to enjoy a glass and don’t want to take an HRV hit the next day, how many glasses can I have?  With this I will know my own tolerance and be able to guide my actions with better data.

Going Ketogenic and HRV

Inspired by a fellow Quantified Selfer at our recent Denver QS Meetup and motivated by multiple guests on Damien Blenkinsopp’s excellent Quantified Body podcast I decided to switch from eating vegetarian to eating ketogenic. And always interested in heart rate variability (HRV), I wanted to look at the mix of going ketogenic and HRV.

I won’t go into too much detail about ketosis and its reported benefits. At a high level you switch your body over from sugar (glucose) burning to fat burning (ketones). To do this I was going from a very carb heavy diet to one that severely limits carbs and moderates proteins while ramping up fat. Imagine my long suffering vegetarian wife’s surprise when she came into the kitchen to find me chomping on bacon with a coffee full of butter.

One element of the switch involves a state called “keto flu” which is the body suddenly finding no carbs available and sending pretty clear signals to the brain that its time to find some carbs. Proponents of the diet tend to downplay the effects calling it a euphemistic “short term discomfort” but I have to say it felt like I had been hit by a truck.

Going Ketogenic and HRV

Me no like keto flu

Of course being a Heart Rate Variability (HRV) enthusiast I had to check the impact of the transition on my resting heart rate and HRV.

My Question

What impact would the transition to ketosis and its associated “keto flu” have on my HRV? What did the load on the body look like?

What I Did

I measured my resting heart rate and HRV for three weeks during the transition to ketosis. I was also measuring my glucose and ketone production so could verify when the transition was complete.

How I Did It

I measured my heart rate and HRV reading using a Polar H7 heart rate belt that was sending data to Marco Altini’s Heart Rate Variability Logger four times a day. I would take a reading first thing in the morning, later in the morning after traveling to work, after lunch and before bed. Once each morning I would use a glucose meter and a Ketonix breath ketone analyzer to check the trend in my transition to ketosis. Toward the end of the period I used a Precision Xtra ketone meter to verify with surety I was in ketosis.

What I Learned

Transitioning to ketosis is a real butt kicker of both mood and heart level activity. First my mood went very dark and on day two I almost tore my car’s steering wheel out of its moorings when I couldn’t find a parking space. Keto flu for me was like a bad hangover mixed with a flu-like dizziness. For me it took two weeks to transition to ketosis.

At the physiological level my resting heart rate over the period showed a large amount of load on the body. You can see from the graph that my resting heart rate popped up almost immediately. In the middle of the transition I was getting a readings of 85 to 93 Beats Per Minute (BPM) and that was unusually high. I am usually in the high 60’s to low 70’s.

Going Ketogenic and HRV

HRV showed a similar story. The four readings through the day showed that my HRV was lowered in the early day readings but tended to be similar in the later day readings.

Going Ketogenic and HRV

HRV has a circadian rhythm. As with our energy levels, it tends to drop over the course of the day. You can see that in the baseline. The slope of the curve was still negative while in the transition, but the slope was greatly reduced. I would have expected the slope to be the same and the lower start point end with a lower end point, but that was not the case. Perhaps the body has a baseline beneath which it won’t drop based on health and when in load the impact is in the beginning of the day when the body should be able to relax.

From an HRV perspective it looks like transitioning to ketosis has a similar effect on the body as being overtrained as an athlete.  The body’s Parasympathetic Nervous System seems to be less capable of putting the brakes on the system and bring the body to a relaxed state.

The happy news is that once through the whupping you get from keto flu the benefits are as advertised. I dropped 12 pounds and feel great. I have a lot of energy and feel very clear of mind. All the better to conduct more studies in the future.

Hitting the Slopes

Have you ever felt that your willpower drop over the course of the day? It is true that Heart Rate Variability (HRV) has its own circadian rhythm which I call hitting the slopes. Here is two weeks worth of my HRV averages taken at four different times of the day:

Hitting the Slopes

The slope of the line connecting the four readings is the natural shape of energy that I have during the day. To increase willpower stamina and improve performance in my negotiations I want to see if there are ways to flatten the slope of that line without losing the high readings early in the day.

To understand which variables may extend the energy I have for negotiations I found a service called Whatify that helps set up and randomize conditions for testing. Now I can A/B test elements that may affect the slope of the day.

First I have to reduce Heart Rate Variability (HRV) to a single daily number and then test variables across that number. This one number is the slope of the readings. I derive that by making the X axis the hour of the day and the Y axis the rMSSD read at that time. I then use the SLOPE function in excel to derive the number.

The first variable I am going to test is exercise. Does 30 minutes of morning cardio change the slope of the line? Stay tuned and we find out using Whatify.

HRV Reactions to Presentations @ TEDx

HRV Reactions to Presentations

My wife and I attended TEDx Mile High – “Ideas Unbridled” in Denver yesterday. I measured my heart rate variability (HRV) during each speech and on the conclusion of each rated it on how much I thought I enjoyed it. I wanted to compare my mental rating of the speeches and my physiological reaction to the same. Would the reactions match? Or was my physiology detached from the proceedings and my consumption of the speech was only a mental exercise?

I listened to twelve speeches over the course of the afternoon. The general arc was that the first four speakers I did not connect with, the fifth was a very inspiring speech, the next few were interesting, the last four were really good with the final one being absolutely great. So if I were to draw out my enjoyment curve by hand, it would look something like this:

HRV Reactions to Presentations

My wife and I discussed the speeches as we walked home. I remember telling her I liked the middle spike speaker (Eric Kornacki) and the final speaker (Teju Ravilochan). I also mentioned that I liked some of the other speakers but I referred to them by topic rather than by name. I used descriptors “the Polar Vortex guy” or “the Twitter guy” and “the Visual Mantra Woman.” That was my subjective memory at work.

I had rated each speaker immediately after their speech on a scale of 1 to 10, therefore I had data recording my immediate reaction to each speech. Here is that curve:

HRV Reactions to Presentations

During the actual experience of the speeches I had enjoyed remarks by Jesse Zhang and Chris Hansen nearly as much as Eric and Teju’s speeches, but because they sat in proximity to each other and Teju I could not recall them as well.

Finally, I pulled the data on my HRV, scaled it so I could lay it side by side with my mental assessment and you see that graph here:

HRV Reactions to Presentations

My heart rate variability tracked closely with my mental assessment of each speech. The Pearson correlation between the two measurement arrays is .84, meaning my mental assessment of enjoyment had a very strong relationship with my physiological reaction to the speeches. It appears my enjoyment of the lineup of speakers was gradually increasing although my mental assessment was more extreme at the moment.

So the physiology and the mental assessment track together. When I am delighted, entertained and viewing material meant to be engaging my HRV reaction can be a proxy for how much I enjoyed and connected with what I was seeing.

As I find note taking boring, I see a few potential techniques to develop here. Perhaps when interviewing candidates for a role I no longer need to take notes, but can simply compare HRV readings after the discussions. Or I can rent myself out as a speech meter and simply sit in rehearsal presentations and upload the HRV data afterward. When people ask “What did you think?” I can say “I don’t know, look at the data and you tell me!”

And The Winner Is..

Vapor Lock by a wide margin. A lot of interesting contributions to include:

  • cranial crash
  • Brain Choke
  • Lizard State
  • hyperlock
  • Blankout
  • Neural Network Denial-of-Service Attack

The last one is great. However, I think the technically correct term would be “Parasympathetic Nervous System Allowing Denial-of-Service Acceleration!”

Thanks all for your votes. We’ve crowdsourced a term!

Reader Poll: Name that Freak Out State

I have prepared my speech for the Quantified Self 2015 Conference and have one last finishing touch to do and I thought I would reach out for your help. The speech is about stress states while interacting with colleagues. I have used many words in this blog to describe this stress state before to include terms like Upset and Parasympathetic Flatline. But these terms don’t capture those electrifying moments where things just freeze. Let’s name that freak out state.

Name that Freak Out State

What I am trying to describe is more specific in the social environment and the term needs a little punch. It is that state brought on by any trigger that puts your body in the Fight/Flight mode at that exact moment you actually need your brain. It is the moment when all your blood moves to the back brain, hands and feet getting you ready to physically respond to danger. And you are sitting in a conference room. It is freezing up when you talk to the boss. Going blank when you get on stage to speak to a group. Those terrifying moments when you can’t recall simple facts you know you have in your memory.

I would like to get your input on a good term that captures this state in a vibrant way. The term the group likes most I will use my in QS15 speech and will start using to describe this state hereafter. Let’s crowdsource a term and see if it sticks. To the poll:

Facing the Big Boss

Have you every had to give a briefing to the Big Boss, the Boss above the person you report to? And in that have you ever gotten this look?

Uhappy Big Boss

And when you got that look your brain just froze? You could not think of what to say? The start point for my work in Quantified Self was to try and understand that “freeze” phenomenon and how to train myself to experience it less. I negotiate a lot for business and my hypothesis was that control of physiological reactions in meetings could make me a more effective negotiator.

I had an excellent opportunity to see how I was doing this week as I briefed not one, but SIX Big Bosses. Nine people total were in the room. One Boss had showed up uninvited because he opposed the concepts being discussed. And to make matters even more fun, I was told I was the primary presenter thirty minutes before the meeting. After hearing that I thought, “This will be a great HRV reading.”

The meeting was on a controversial topic and several of the Big Bosses did not agree on how to resolve it. I had been asked a few weeks earlier to help create a resolution. We were scheduled for an hour. There were two points in meeting I remember feeling the “brain freeze” moment and had to push on by looking at the slide and restarting my mental engine. Because of the late notice that I was the presenter I could not use my standard practice of memorizing the material prior to a high intensity presentation. Here is my reading for the session:


This reading recalls the shape of the meeting very well. At the start each of Big Bosses tried to steer the meeting toward a resolution they thought was best. Big Bosses can’t help it, they get paid to steer. The Biggest Boss kept coming back to “let’s let him go through the material.” The dark blue from interval 426 to 2996 was me trying to get a word in edgewise.

In the middle of the meeting I had made my points and the Big Bosses began debating the merits of the resolution. As the spotlight moved from me I did deep breathing, listened and took notes. My memory of that period was that my brain was turned back on and I could feel a lighter feeling in my chest and head. The reading shows that I dropped from Fight/Flight as indicated by the white spaces from interval 2996 to around 6000.

Then the Biggest Boss said something to the effect that the resolution I had presented was incomplete. You can see around interval 6000 I go back into Fight/Flight as I was trying to explain how the missing part he was concerned with actually was completed. This lasted for a good period because other Big Bosses saw this as an opportunity to re-introduce their specific personal points and we were off and running. It was in this period I recall a specific “freeze” moment regarding a question on a detail that I resolved by having the group look at a different slide.

Finally I was able to get the Big Bosses to turn to the last slide where there was a collective “Oh, here it is” and you can see around interval 8900 my physiology begins to relax. The part of the resolution they were looking for was there. To my recollection the room relaxed as well. Some jokes where shared and people began to prepare to summarize and end the meeting.

During this hour long meeting I was in Fight/Flight 46% of the time, a full 27 minutes. I can’t reveal any details of the meeting, but I can believe that quality of my answers was more reactive and less thought out during those two periods. My personal variability training did make an important contribution as I was able to break up the 27 minutes into two periods that each had a specific topic I was “fighting” to make. In the first period I was concentrating on getting my main points across. Once done I was able to use my breathing and get myself to a relaxed state where I had ticked the box of “points made.” When the second period started I was only “fighting” to show the one completion point. I believe that if I had not allowed myself a completion state in the middle I would not have been as focussed on a single point which I was able to make in the end.

To see how much the environment like a meeting can change very rapidly, I had the opportunity to measure a meeting immediately after the meeting recorded above. As in I walked from the conference room for that meeting to the office for the meeting in a period of five minutes. I already had the kit ready so I just hit “record” for the second meeting.

In this second meeting I was brainstorming with a colleague on how to handle a problem that would play out over several months. There was no urgency, the colleague and I get on well and we were coming up with good ideas. Here is the reading:


That means I came from a pretty intense Big Boss meeting where there was a lot of Fight/Flight, did a BreatheSync session for two minutes and entered the second meeting. In this one there was very little Fight/Flight at all and it was a very productive 35 minutes.

Breathing tools, understanding how the physiology reacts when meeting with the Big Bosses and finding the balance between Fight/Flight and relaxation can improve both how you prepare, and how you ramp yourself down when in an intense situation. And these same tools allow a fast transition to a new environment where you can be productive as appropriate for the situation.

I will be presenting more about how I use heart rate variability at the Quantifed Self Conference and Expo in San Francisco June 18 – 20. I look forward to it and I look forward to meeting many of you there.