There seems to be a growing social media chatter about research conducted at the Heart Math Institute ( on shared electromagnetic fields between horses and humans, which purportedly explain why we feel good around horses. Intrigued that there may be sound science behind the connectivity, peacefulness, and overall exceptional feeling that horse enthusiasts, including myself, consistently experience, I was eager to dig in.

The Heart Math Claim

The Heart Math Institute claims that scientific evidence conducted by Dr. Ann Baldwin and Dr. Ellen Gehrke indicates that horses can sense, and respond in kind, to the emotional state of humans – not only when we are afraid, but also when we are feeling positive emotions such as appreciation. Apparently, they do so with an electromagnetic field, much larger than our own, projected by their heart which surrounds and influences our own heart rhythms in a positive way. Further, horses are said to possess a coherent heart rhythm (indicative of a calm state of well-being) which can further impact our mental state and explains why horses make us feel good.

An illustration of a rider on a horse with heart waves.

(Artist: Valerie Eric © Sarah Barnes)

A Word about Heart Rate Variability (HRV)

Heart rhythm is measured through electrocardiography (ECG) recordings to provide a reading of Heart Rate Variability (HRV). Unlike Heart Rate (HR), which measures the number of heart beats per minute, HRV measures the changes in the intervals between consecutive heart beats. The fluctuations of a healthy heart are complex, and variability means the heart is flexibly coping with uncertain and shifting environmental and psychological challenges.

In its most simplistic terms, a high HRV reading generally suggests the heart is adjusting quickly to changing circumstances and indicates good health, active coping, and well-being. HRV has been used to reliably assess stress reactions, behavioural dysfunction, and emotional states in humans, horses, and other farm and companion animals (e.g. Rietmann et al., 2004).

It is a stretch to call this unpublished report a “study”; I would instead call it a curious researcher hanging out with her horse thinking nice things.

Heart Math Science

My first sleuthing task was to find the original research by doctors Baldwin and Gerhke cited by the Heart Math Institute. In the first study, Ellen Gehrke monitored her horse’s and her own HRV while sitting in a paddock with her horse and thinking thoughts of love and appreciation for him (2011). Her HRV showed a coherent pattern (indicative of a positive state); soon, her horse Tonopah’s HRV also shifted to a more coherent pattern. The Heart Math Institute’s interpretation was that “Tonapah was able to sense and respond to the emotional information carried by the energetic field of Ellen’s heart” (

First, it is a stretch to call this unpublished report a “study”. I would instead call it a curious researcher hanging out with her horse thinking nice things. Second, the findings (correction, finding since we have a sample size of one) support a human influencing a horse’s psychological state, rather than the other way around, which runs counter to the Heart Math claim that horses’ greater electromagnetic heart fields positively influence our own. Finally, the interpretation goes well beyond the data; clearly we cannot glean anything about Tonopah’s ability, or lack thereof, to read emotional information generated by Ellen’s energetic heart field from these HRV readings.

The Heart Math Institute maintains that this result was “replicated successfully with several different human horse pairs” ( Here is the real story: After an extensive search, I found four published studies by these authors. A 2012 study by Baldwin and Gehrke looked at HRV in nine horses used for equine facilitated therapy to see how the horses were coping with the potential stress of their occupation. The study did not explore or measure the riders’ HRV or any potential synchronization between horse and rider.

Gehrke’s 2016 study explored horse-to-human heart connectivity more directly, but with a sample size of two (one coach/rider dyad, and one coach/rider/horse triad) – in effect, a sample size of one, as only the triad included a horse. Although the coach’s HRV increased during the sessions, and both coaches and riders experienced positive emotions when the horse was present, any comparisons about synchronized heart fields was not possible as there were technical issues and the rider and horse HRV recordings were not readable. The authors claim that “positive emotions in humans reflected in healthy HRV patterns was enhanced in the presence of horses during triad-coaching sessions,” but their data (HRV readings from one coach) cannot support this interpretation.

I hoped I might find more convincing evidence for interconnecting heart fields in recent publications by Ann Baldwin and colleagues (2018, 2021). In her most recent study, Baldwin had 24 residents of a senior’s care facility engage in 10-minute stroking sessions with one of three resident horses – Prissy, Joe, and Herman. Baldwin hypothesized that the seniors’ HR and HRV would increase during stroking, indicating increased arousal (HR) and increased well-being (HRV), and that HRV would shift toward the low-frequency intervals characteristic of the horses, also indicative of calm and well-being. Although HR did increase, HRV did not, nor did HRV shift toward the lower frequency of their horse partner. Indeed, contrary to predictions, there were no significant changes in any parameter over the four weeks of the study. Seniors showed more engagement with the facilitator during the sessions and reported positive feelings of connection to the horse at the study’s conclusion. However, even the authors admit that more research is necessary to indicate that horses and humans connect and communicate through HRV synchronization (Baldwin, 2021).

What research to date has failed to show is that there is a unique benefit from interacting with horses that transcends the well-documented positive psychological and physiological benefits of interacting with any animal.

There are also two unpublished dissertations cited on the Heart Math Institute site (Cicėnaitė et al., 2016; Dampsey , 2017). The dissertations have yet to been published, nor was I able to find any other publications about horse and human hearts from the primary or secondary authors.

There are good reasons why scientists do not cite unpublished research as support for a particular claim. When a study is published it means that manuscript submissions have undergone intense scrutiny from several scientists who are regarded as experts in that field, and who collectively decide whether the methodology, the interpretation, and the overall science are sound. Many more papers are rejected than accepted, and accepted papers are nearly always sent back for revisions.

This is an integral part of the scientific process and how we can feel assured that published scientific findings accurately represent the knowledge in the field at the time. Is it truth? No. Subsequent research could uncover new discoveries that question or refute what came before, and in this way, science is continually self-correcting. Without peer-review, these papers carry as much weight as any opinion we might encounter from anyone’s social media rantings.


A girl hugging a horse.

There is no doubt that horses make us feel good – but there is no proof that they offer any additional overall health benefits over any other animal. Most horse owners would disagree! (zzzdim –

How Animals Affect Body and Mind

The Heart Math studies, along with a substantial and convincing body of research, indicate that people do better when they interact with horses – they get excited, find more meaning and purpose in their lives, report fewer psychological problems and experience greater quality of life during the time of the study (e.g., Dableko-Schoeny et al., 2014; Lee et al., 2019; Romaniuk et al., 2018). What research to date has failed to show is that there is a unique benefit from interacting with horses that transcends the well-documented positive psychological and physiological benefits of interacting with any animal.

Companion animals have been shown to reduce loneliness and increase affiliation, social engagement, responsiveness, self-esteem and overall psychological well-being (e.g. McCardle et al, 2011). Physiological benefits include decreased risk for cardiovascular disease, shorter recovery time after heart attack, and improved overall physical health (e.g. Allen, 1991; Friedman et al, 2000). Even watching an aquarium of fish facilitates relaxation, lowers blood pressure, and reduces stress responses when performing the stressful task of reading aloud. (Katcher et al.,1983).

Participants having to complete the anxiety-provoking task of solving math problems experience the least stress in the presence of the non-judgmental support offered by their dog, and the highest when in the presence of a close friend (Allen, 1991). Ultimately, if horses offer no additional health benefits over any other animal, it would arguably be infinitely more affordable to stick to hamsters.

What We Do Know About Heart Synchronicity

Casting a wider net, I looked to see what other researchers had found about the potential transmission of positive and/or negative emotions between horses and humans, and HR or HRV synchronicity. There is some evidence that our emotional state (particularly anxiety) can be transmitted to our horses, but even this seemingly obvious association is not consistent across studies.

For example, an ingenious study by Linda Keeling and colleagues (2009) had non-professional horse riders lead or ride a horse four times between two designated points. They were warned, just before the final pass, that a research assistant would be opening an umbrella. Not surprisingly, participants’ HR lowered with each successive pass but spiked when they learned about the umbrella. Interestingly, the horses, who were clearly not privy to this information, experienced the same HR spike even though no umbrella ever made an appearance.

Mareike von Lewinski and her group, however, did not see a similar rider-to-horse anxiety transmission in high-performance dressage rider-horse pairs performing at an actual horse show and an identical dress-rehearsal without spectators. Although riders’ stress responses rose significantly in the actual horse show vs. the private dress-rehearsal, their horses’ stress responses did not change. Horses found all performances equally stressful, and unlike the anticipated but fictitious popping umbrella, did not seem to be influenced by their riders’ rising anxiety (Mareike von Lewinski et al., 2013).

There is some evidence that our emotional state (particularly anxiety) can be transmitted to our horses, but even this seemingly obvious association is not consistent across studies.

Other research by University of Guelph researcher Katrina Merkies offers yet another piece to this puzzle indicating that horses, free to interact with blindfolded human participants, exhibited slower and calmer behaviour (lowered HR) when interacting with a person who was physically stressed (an elevated HR due to exercise) or psychologically stressed (elevated HR due to a fear of horses – where on earth did they find these volunteers??) than they were with a calm person with a normal HR (Merkies et al., 2014). Further work by this group found that horses were most stressed when alone, calmer in the presence of an inexperienced horse person, but more attentive with an experienced person, and, unlike many humans, exhibited no mental health prejudices, reacting just as calmly to participants suffering from PTSD as they did to those without (Merkies et al., 2018).

Chiara Scopa and colleagues found that horses appeared calmer and had higher HRV ratings (i.e. more relaxed) when groomed by familiar humans than unfamiliar humans (2020). Similarly, Jo Hockenhull found that horses became calmer when led through a short obstacle course when the handler was familiar to them, but that familiarity provided no such advantage for their human handlers who were more stressed handling their own horse than an unfamiliar one (Hockenhull et al., 2016).

As for human/horse heart synchronicity, Hockenhull found that only six of the 34 pairings showed any correlation between horse and handler heart rates. She concludes that the horse/human HR relationship is not straightforward and many intangible, difficult-to-measure factors contribute to this inconsistent picture.

If Not Heart, Then What?

I know I am a member of the most privileged group in the world to have horses in my life. They keep me fit, allow me to connect with nature, and they feed my soul. Anyone reading this article knows there is something profound and unique about this relationship that is different than a relationship with a dog or a cat or even a human. As yet, we still do not know why. Merging electromagnetic heart fields offers a potential explanation worthy of being put to the empirical test. To date, we do not have the evidence to say that this is so.

As an untested theory, I feel more connection with the writings of Boris Levinson (1984), an early pioneer of animal assisted interventions. He proposed that in our increasingly technological and industrialized world we have become alienated from nature and impoverished as a result (note that his writings came well before smart phones and social media!). He suggests that we can restore a healing connection with our own unconscious animal nature by fostering a relationship with a companion animal who sits on an intermediary line between the wild animal in nature and human.

If this is so, perhaps horses take us further into this realm because their proximity to nature and to the wild is closer still, the connection more tenuous, their admiration that much harder-won, and their gift to us so immense.