This history account was originally drawn up to clear up controversy around Mr. Dan Winter, an electric craftsman and sacred geometry lecturer who widely published his own, mostly distorted versions of original research carried out by Institute of HeartMath (US) and later also concepts and developments of TrigunaMedia (Netherlands). It is especially meant for those who felt misled and confused by Mr. Winter and may be less relevant to others as there are sufficient other resources. In Feb. 2013 and Sept. 2015, an updated and expanded version was co-edited by Dr. Rollin McCraty, Director of Research of Institute of HeartMath and Frank van den Bovenkamp of TrigunaMedia, which is posted below.

A brief history of heart coherence research

The origins of heart coherence research can be traced back to the Institute of HeartMath (IHM), a research group located on the West Coast of the US in the early nineties. The research focus at that time was on investing the physiological correlates of both positive and negative emotional states. At that time, there was very little research, if any on the physiological correlates of positive emotions. Using many physiological measures (EEG, skin conductance, heart rate, etc.) they found and were the first to discover and publish that emotional states tend to be reflected in the patterns of the heart rate variability waveform (American Journal of Cardiology, 1995). More recent studies have independently confirmed their findings and have shown that discrete emotional states can be detected with 75% accuracy from only the HRV patterns. They also explored whether it was possible to extract valuable (psycho-) physiological data from the ECG spectrum, which already had a well-established history in the medical literature but had not yet been examined in the context of psychological and emotional states .

The Institute of Heart Math (IHM) has since scientifically developed and published numerous peer reviewed scientific papers on the concept of "coherence" which they use both in a broad context and as a specific measure of HRV patterns. In the latter context, it essentially means that the majority of the HRV (Heart Rate Variability) spectral power is concentrated into one single peak (frequency) near 0.1 HZ which is the resonant frequency of the cardiovascular system . This they referred to as physiological coherence.

Although coherence as such as a peak in the power spectrum can be observed to be created by the autonomic system's response to monotonic paced breathing at 6 breaths per minute, IHM also demonstrated that this state naturally emerges when people are in sustained positive emotional states without any conscious change in breathing. IHM attributes great physiological and psychological value to this state, and for that reason calls this "coherence". The Heart Math method is not based on the full electrical ECG spectrum, only on beat interval, which is derived from the inter-beat-intervals either from the ECG or a pletysmographic (pulse) sensor.

The HeartMath team also introduced the term Internal Cardiac Coherence ("ICC") was coined in order to distinguish a second physiological state they observed when people we are able to shift into a very deep heart-focused state. They termed the subjective state at that time as internal quiescence, which was associated with a technique called point zero. IHM determined that for the masses it was best to focus on HRV coherence training and not the state they termed internal coherence, although they did acknowledge this state and cautioned against too much focus on training to the this state as it involved shifting to a low HRV state.

The first HRV coherence training system was called the Freeze-Framer (now called the emWave) which has gone on to the bestselling device in the entire biofeedback industry.

In the very early stages of IHMs research, they heard about a craftsman working in an electric motor repair shop, Dan Winter, who was talking about measuring the frequencies of the heart and as IHM were interested in this topic, they invited him for a short visit to their facilities which he accepted. Dan Winter suggested to the group at IHM that the space between the peaks in an ECG spectrum would have the exact spacing of the Golden Mean ratio when people were in a loving state. In talking with Dr. Rollin McCraty, director of research at IHM, Dan himself did not really understand the details of the types of measurements that he was suggesting, and he had only done them on one person with some equipment that he had gotten on loan from someone else. Dr. McCraty at that time also did not understand what the spectral analysis of the ECG was actually showing as IHM were just finishing the construction of their research facilities. However, IHM spent several months looking into the details and developed a full understanding. Through this process they found that the ECG spectrum was completely controlled by and can be predicted by the HRV patterns, and that Dan Winter assumptions were incorrect. Also they found that Dan’s assumptions were psycho-physiologically unfounded and anyway technically trivial. Dr. McCraty also stated that at the time he invited Dan Winter to visit he was unaware that Dan was being sued for plagiarism. The IHM group did collect data from a couple of subjects while Dan visited, and shortly after his visit he fled the country. He took the very preliminary data they had collected with him to Europe and began promoting his own interpretation of it on his website and during his sacred geometry seminars. Having hardly any research- and no scientific backup at all, Dan's ideas took on a life of their own, resulting in concepts like these:


Around 2001, a working prototype that at least technically reflected the Internal Coherence state described by HeartMath was developed in a lab in the Netherlands (Imaging Lab, funded by Fred Foundation). The prototype used besides ECG spectrum additional ECG cepstrum analysis which Dan Winter claims is his idea. Imaging Lab developed the software, but did not do any research. Frank van den Bovenkamp happened to also be in touch with the lab at that time and it was agreed that a new company, Triguna Media (TGM), would be started to market the prototype. Seeing the beta stage of the technology, lacking research and scientific background and the totally unfounded claims of Dan Winter, TGM immediately started to develop new software and concepts from scratch. This resulted in the HT-PRO-04 (released early 2005), which was successfully marketed for several years. The main purposes of the new software were:

       A) To provide an attractive and professional environment for users (appealing design, biofeedback and -games, printout options)
       B) To provide a tool to do research (e.g. by including ICC- and heart rate history graphs, record and replay options, HRV spectrum)

The challenge consisted of two parts:

       A) Formulation of a consistent (verifiable and falsifiable) bio-physical and mathematical basis
       B) Professional testing

Unfortunately it soon became furthermore apparent that Dan Winter's claims which he had already been widely promoting, no matter how dazzling they appeared, were not only conceptually but even technically mistaken, presenting a case of ignominious mis-education. This became all the more noteworthy, as his claim of being the sole proprietor of the concept turned out to be challenged in the first place. In particular (referring to above samples even today on his website) we can summarize resp.:

      A) There is no such thing as a (Phi-) geometric cascade in, or even related to the coherent ECG spectrum;
      B) There is no indication, let alone evidence that a person's heart rate is a measure of an "emotional index", in that a slower heart rate means
           a person is more "head-centered" and faster means "heart centered" (in fact the research data from IHM shows this to be completely false) or etc..
      C) There is no mathematical basis for "Phi" (Golden Mean ratio) in the ECG spectrum or cepstrum, and in particular, as Golden Mean ratio, like the
           term says, is a ratio and hence a dimensionless number, it is therefore impossible for it to represent a cepstrum index value, as the cepstrum base
           has a dimension (1/ Hz, i.e. time-interval index).

The question naturally arises then, if Dan Winter is the sole originator of the concept as he claimed, how could he possibly not have understood its basic premises?

The conceptual and mathematical basis for Internal Cardiac Coherence (ICC) is now formulated as follows:

      A) Regular heart rate episodes (Low HRV) reflect an healthy individual's capacity of quiescence and focus, whereas general HRV power is an indicator
           (directly or indirectly) of vitality and health;
      B) Nature's formula to bring these apparently opposite requirements together, is harmonic inclusiveness, commonly attributed to the HRV spectrum;
      C) This can be demonstrated by numerical analysis, and is confirmed by the Gaussian distribution of ICC samples in healthy (not normally abnormally
           low or high HRV) subjects;
      D) A complete ICC session is normalized (typically on a 0 to 100 scale) by quantifying the Gaussion distribution, producing what is referred to as the
           Dynamic Index of an entire session.

Further backgrounds include breakthrough insights in wave matrix physics, applied to bio-physiology (especially the geometric origin of selective color perception) and contemporary theory on bio-psychology of the Indian philosopher Shrii P.R. Sarkar.

Meanwhile, the second part of the research challenge, testing the concept and psychological implications of ICC, has been taken over by the new CardioGem-5, which can perform the Gaussian analysis (so called "Quick Scan"). In our database you can find and download a growing number of recordings with comments in the attached session report.

Conclusively, over the past two decades the concept of both physiological coherence and Internal Cardiac Ccoherence have greatly matured, not unlike the time it took for HRV to become understood and recognized. As demonstrated by HeartMath and TrigunaMedia, ICC is different from "physiological coherence" as described above. Dan Winter, who has been sales representative for TrigunaMedia for some time, appears to insist on his phantasmogorical version of heart coherence in order to promote his own unfounded ideas. TrigunaMedia is currently collaborating with some of the original research groups in marketing and further development including the new NeuroGem (brain coherence), who fully endorse this brief summary.

More on Dan Winter and his history of proprietary issues can be find on

Update june 2010: In what seems a final attempt to seize his day, Dan Winter embarked on the development of his own application called "TheLoveTuner" in sept. 2009. After repeated "announcements of announcements" the effort appears to have got stuck in a rudimentary version without even reaching the functionality of the earliest primitive HeartTuner. From the recent expiration of his domain and no longer "announcing announcements", it seems he's finally learned that it takes more than stubborn believe in one's own grandiosity to develop a mature concept and product.

Update feb. 2013: Dan Winter recently launched an applet (called "Heartsring") which does, or rather attempts, a very low-resolution breathing rhythm measurement. Again he associates his applet with heartcoherence and he makes several technically wrong, and (psycho-) physiologically unfounded claims. Moreover, Dan Winter utterly contradicts himself by trying to sell a device that claims to do the same (in a crude manner) as HeartMath's, which he totally debunks on another page. In the iTunes store Dan Winter unusually refers to himself as "Daniel Winter", propably hoping that will fire fewer embarrassing Google search results.

Update march 2013: In Dec. 2012 Dan Winter launched "Heartsring", his crude implementation of the HeartMath method, in the iTunes store. The next day already he announced that his Heartsring app was listed as top-grossing on No need to mention, that it was never even there in the first place. Currently the average customer rating in the iTunes store is not up because there are too few ratings yet - the result of three months "top-grossing". In fact, there is only one rating which was posted at least a month ago. And that rating effectively states that Dan Winter's HeartsRing app may potentially be useful but does not actually work.

For this moment we have placed a notice on to inform visitors and dissociate Dan Winter’s applet and claims from research carried out, and principles and technology developed by IHM and TrigunaMedia.

Februari 2013
Rollin McCraty, Institute of HeartMath,
Frank van den Bovenkamp, TrigunaMedia,

Comments on "Statement by Rollin Mc.Craty on the HeartTuner, Institute of Heart Math"

In August 2003 Stan Tenen of Meru Foundation posted this statement on the seized website obviously for the purpose of exposing further proprietary issues related to Dan Winter. In his statement, Dr. Rollin Mc.Craty also made comments related the original Heart Tuner, which needed a little redress. The original statement is copied below in its entirety with comments inserted (bold italic) where the HeartTuner and its earlier concepts are discussed.

Statement of Rollin McCraty
Boulder Creek, CA., August 2003

The statement below was written by Rollin McCraty, Executive Vice President and Director of Research for the Institute of Heart Math, Boulder Creek, California. The Institute of Heart Math and Meru Foundation are completely independent, working in different fields, and have no relationship -- except with regards to damage done by Mr. Winter.

Dan Winter has suggested that the only measure of heart coherence requires something he calls the "cepstrumin," which is basically a spectrum of the power spectrum of the ECG itself. He has also claimed that we at HeartMath have never measured coherence. We have published many papers on this subject which are freely available on our web site ( I suggest the monographs titled:
• The Energetic Heart and
• The Appreciative Heart.
• Updated early 2013
• The Coherent Heart
• Coherence: bridging personal, social and global health
• And many others available on the website
[sources: IHM basic research]
There will also be a chapter that is being re-published as a monograph titled: Physiological Coherence, available in the fall of 2003, that discusses this subject in depth.
The following quote from the Physiological Coherence monograph captures the essence of our use of the term:

"It is the harmonious flow of information, cooperation, and order among the subsystems of a larger system that allows for the emergence of more complex functions. This higher-order cooperation among the physical subsystems such as the heart, brain, glands, and organs as well as between the cognitive, emotional, and physical systems is an important aspect of what we call coherence. It is the rhythm of the heart that sets the beat for the entire system. The heart's rhythmic beat influences brain processes that control the autonomic nervous system, cognitive function, and emotions, thus leading us to propose that it is the primary conductor in the system. By changing the rhythm of the heart, system-wide dynamics can be quickly and dramatically changed.

"We use the term "coherence" in a broad context to describe more ordered mental and emotional processes as well as more ordered and harmonious interactions among various physiological systems. In this context, "coherence" embraces many other terms that are used to describe specific functional modes, such as synchronization, entrainment, and resonance.

"Physiological coherence is thus a specific and measurable mode of physiological functioning that encompasses a number of distinct but related phenomena. Correlates of the physiological coherence mode, which will be considered in further detail in this monograph, include: increased synchronization between the two branches of the ANS, a shift in autonomic balance toward increased parasympathetic activity, increased heart-brain synchronization, increased vascular resonance, and entrainment between diverse physiological oscillatory systems. The coherent mode is reflected by a smooth, sine wave-like pattern in the heart rhythms (heart rhythm coherence) and a narrow-band, high-amplitude peak in the low frequency range of the HRV power spectrum, at a frequency of about 0.1 hertz."

Mr. Winter also appears to insist that heart coherence occurs only when the spectrum of the EGC (over 8 seconds) exhibits a standing wave pattern. He also claims that this spectrum is a measure of love. I cannot fully agree with this for two important reasons. First it is not grounded in an understanding of healthy function and how the ECG spectra relate to the dynamics of the underlying physiological systems. Secondly, repeated controlled studies indicate that love and other positive emotions are more frequently correlated with a very different physiological mode in the majority of people.

There is not even such a thing as a "standing wave pattern" in the ECG spectrum in any conventional manner. The popular comparison with a "laser beam" makes no sense either. Mr. Mc.Craty is right that positive emotions (e.g. "heart intelligence") imply a far different and more intricate electro-physiological theme than such plain model. In very contemporary wave matrix physics however there is a format which could roughly be referred to as "standing wave" which serves as a generic cause of general periodic patterns, but this is probably not what Dan Winter referred to.

It is true that Dan did visit our research facility for two days at the time we were just completing its construction and before the lab was set up. He did indeed suggest to us that we look at spectral analysis of the ECG. I thought then and still do that this was a good idea; however, when we looked deeper into it we found that the appearance of the peaks in the power spectrum of the ECG that look like standing waves are completely dependent on the inter-beat-intervals in the ECG (the time between heartbeats). All one has to do in order to create the “standing wave” pattern in the ECG spectrum is to make the intervals between heartbeats the same (very low heart rate variability (HRV)).

This is technically and by definition correct, however..

There is direct relationship between the heart's rhythm (HRV patterns ) and the ECG spectrum. In other words, you can know what the ECG spectrum will be if you know the HRV pattern. In addition, the spacing between the peaks in the ECG spectrum is dependent on the interval length between heartbeats (heart rate). In order to generate an ECG spectrum with golden mean-related spacing between the peaks, one must have very low HRV and a heart rate of exactly 97.082 beats per minute. For this reason, and to avoid confusion, we call this the "low HRV mode".

Here Mc.Craty could have ridiculed "Phi" spacing between peaks altogether because it is utterly trivial as was explained above.

Secondly, true Internal Cardiac Coherence (ICC) cannot be retrieved from a low-HRV episode itself, only from the ECG spectrum, having a known geometry. Therefore, by definition a technical HRV-ECG relation is pyscho-physiologically trivial, and vice versa.

The second issue is that the majority of people do not enter the low HRV mode when they are experiencing positive emotions.

Precisely - any emotional extroversy would issue a lower final ICC reward. ICC has nothing to do with positive or negative emotions, because it has nothing to do with literal emotions in the first place.

The majority of people instead exhibit a sine wave-like pattern in their heart rhythms. This is a very dynamic and efficient physiological mode that has been observed and recognized as a healthy functional mode in the scientific literature since the 1950s. This sine wave pattern in the heart rhythms is associated with improved health outcomes and increased systemic HRV.
We have several times observed that indeed monotonic breathing, which simply is required to induce a sine wave-like HRV, increases the HRV. Also it dramatically reduces Internal Cardiac Coherence. (I think we have to agree on how these states are going to be defined – we coined the terms , but I am happy to come to an agreement on this – they are compedativenot competitive states, just different.)
It is also important to point out that there is no way to really measure a person's subjective state. A person can be in a very loving state and the HRV pattern will not always indicate this, and if the HRV pattern does not reflect it, neither will the spectrum of the ECG. However, with that said, the most reliable indicator we have found that can discriminate positive from negative emotional states is the heart rhythm pattern.

Sure enough one cannot breathe monotonically while emotionally imbalanced. But Mr. Mc.Craty may like to see how the CardioGem responds to "subjective" states..

This low HRV mode is a valid transient state that is associated with very low resultant autonomic nervous system outflow. The main point here is that this low HRV state (what Dan Winter calls heart coherence) -

This is biased - Dan Winter would never call low HRV state coherence (nor the way around).

[Comments added by Rollin McCraty, feb. 2013]
This is the signature of the state we named and defined – Dan did not even know what HRV was so you are correct – but the fact remains it is a state specific low HRV state. That’s not a bad thing when understood but it is not something that should be cultivated by individuals with health problems. However as a (momentary) result e.g. of meditation by a healthy subject, we observed it can be the result of very high harmonic inclusiveness (see summary above), rather than from a lower autonomic dynamism. I think I need to have a much better understanding of what you are measuring – keep in mind this was written in response to the heart tuner which clearly trained people to this low HRV state. I am way fine with a statement that all my comments were related to the Heart Tuner and lets discuss how the CardioGem is different! [end]

- this low HRV state is not only associated with autonomic neuropathy and autonomic deinnervation (as found in heart transplant recipients) but is predictive of increased risk of sudden cardiac death and all-cause mortality, and also associated with depression, anxiety and a host of other disorders. To train people into this low HRV state goes against all that is known about healthy function and emotional stability. This does not mean that it is not a valid state for advanced practitioners to enter into sometimes, but to do so without the ability to first be able to maintain the physiologically coherent mode is potentially problematic, especially to individuals with heart disease, diabetes or low heart rate variability.

That's right, and therefore Internal Cardiac Coherence, especially the way it is diagnosed and entrained with the new CardioGem 5, requires healthy HRV. To appreciate the richness of the low-HRV state without actually entraining plain low-HRV absolutely requires the epistemology of psycho-physiological synthesis discovered / developed by TrigunaMedia. The practical implementation of it in the CardioGem is by dynamically detecting the known ECG coherent spectrum geometry. This provides effective ICC in a dynamic context, which is then followed by an allover statistical assessment of the entire session.

For the vast majority of people, it takes time and practice to become proficient at entering the heart rhythm coherence mode. Developing consistency and stability in this mode is important in order for this mode of physiological functioning to become established as a familiar state so that individuals can shift into it at will, especially during challenging or stressful situations. Therefore, we have chosen not put focus on the low HRV state at this time.

Mr. Winter also attempts to reduce all the HeartMath tools and techniques and the physiological coherence mode to simple breathing techniques and "relaxation," which is simply inaccurate. He also attempts to reduce the Freeze-Framer to a breathing trainer. Although it can be used for that purpose, the system is designed as a tool to facilitate learning the HeartMath techniques and to help establish increased ratios of physiological coherence. In reality, breathing is equally important to both the physiological coherence and the low HRV mode. Conscious regulation of the breath, if performed properly, can drive the system into physiological coherence.
HeartMath techniques incorporate a breathing element; however, their primary focus is promoting coherence through a positive emotion-driven physiological shift, in contrast to cognitively-directed paced breathing methods. Moreover, positive emotion-focused coherence-building techniques promote a far wider range of benefits, both physiological and psychological, than methods that simply forcing the system into coherence using regulated breathing alone.

Regarding Mr. Winter's statements that we have not given him proper credit: as I stated earlier, he was the first person to suggest to us that we perform spectrum analysis of the ECG, and we have always been very open about that. Mr. Winter was not, however, the first one to ever think of this. There is actually a long history of the use of this analysis method although he is the first that I know of to associate it with emotion, which in an indirect manner is correct. He was in fact given credit by us for his suggestion in one of our most popular books titled, The Hidden Power of the Heart, which contained several pages devoted to this. He was given copies of this book. However, these pages were removed in later editions, after he had started spreading falsehoods about his relationship with HeartMath and his growing legal problems regarding copyright law violations. He has again violated copyright laws by publishing our graphs in his email messages without our permission.
I have no problem giving credit when it due, however, Mr. winter is simply demanding credit that is not due.

This sounds rather familiar.

He did not inspire HeartMath, he did not teach us everything we know, and he never worked for HeartMath, etc.

Mr. Winter initially appeared to inspire TrigunaMedia, however very soon turned out to only teach, and only willing to believe his own rabble-rousing interpretations, and eventually worked as a sales rep. He contributed very little to the first commercial version of the HT and not a single yota to the further (read: the actual) development the ICC concepts resp. the current CardioGem 5.

I sincerely feel that the mission of spreading heart coherence on the planet would be better served if Mr. Winter chose to devote his energies to increasing the methodological rigor of his own work rather than seeking to openly decry and propagate falsehoods regarding the work of others. To do this only harms the larger mission of bringing heart coherence to the world.

LOL - Mr. Winter has propagated a lot of falsehoods about his own work in the first place. Further, as demonstrated above, there appear to be different definitions of heart coherence, which as such has little to do with Mr. Winter. Hence, we use the term Internal "Cardiac Coherence" to avoid confusion.

Rollin McCraty
Director of Research
HeartMath Research Center