If you have ever typed something like does Reiki actually do anything into a search bar, especially late at night after a hard week, you are far from the only one. Interest in complementary practices like Reiki has been growing for years, and a fair question tends to travel right alongside that interest: is there any real research behind this, or is it just something people say makes them feel better?
It is a fair question. Rigorous research on complementary practices has historically been thin, and a lot of what is written about Reiki online leans more on personal testimony than on data. But there is at least one study worth knowing about, because of where it happened and who conducted it. Researchers at Yale-New Haven Hospital studied Reiki on their cardiac unit, and their findings were published in the Journal of the American College of Cardiology, one of the most respected cardiology journals in the world.
What Researchers Wanted to Know
After a heart attack, doctors pay close attention to something called heart rate variability, or HRV. It is a measurable sign of how well a person’s autonomic nervous system, the part of the body that runs largely on its own, is functioning during recovery. Lower HRV in the weeks after a heart attack is linked to worse outcomes, which is part of why medications like beta blockers, which raise HRV by increasing parasympathetic activity, are a standard part of post-heart attack care.
For someone lying in a hospital bed in the days after a heart attack, this is not just an abstract number. It reflects whether the nervous system is still braced, keyed up as if bracing for another blow, or beginning to settle into the calmer, rest and digest state that supports real recovery.
The Yale research team wanted to know something more specific: could Reiki produce a similar shift. Could a noninvasive practice, delivered by hospital nursing staff already trained in it, measurably change a recovering patient’s nervous system activity, and how would that compare to simply resting quietly or listening to calming music.
To find out, they screened 229 hospitalized patients recovering from acute coronary syndrome. Forty-nine met the study criteria and were randomly assigned, within 72 hours of admission, to receive Reiki from a trained nurse, listen to slow classical music, or simply rest while their heart activity was continuously monitored.
What They Found
In the group that received Reiki, HRV increased significantly from where it had started. In the resting group, it barely moved. In the music group, it dropped slightly. The researchers reported that the increase seen with Reiki was significantly greater than what happened with either music or simple rest, and that the size of that shift was similar in magnitude to what had previously been documented with propranolol, a commonly prescribed beta blocker, in an earlier heart attack recovery trial.
This was not an outside therapy brought in as an alternative to hospital care. The Reiki sessions were delivered by the cardiac unit’s own trained nurses, folded directly into standard patient care, with zero complications reported.
— Findings from the Yale-New Haven Hospital study, Journal of the American College of Cardiology, 2010
The study also tracked emotional state using a simple self-report scale before and after each session. Patients who received Reiki reported more of the positive states, feeling happier, calmer, and more relaxed, and less of the negative ones, including feeling stressed, angry, and anxious. And notably, there were no complications reported in the Reiki group at all.
Being Honest About the Limits
It is worth being precise about what this study does and does not say. The researchers themselves were careful in their own conclusion, describing a potential clinical role for Reiki in post-heart attack inpatient care, not a replacement for medical treatment and not a cure. The sample size was small, 49 patients, and the measurement window was short, a single hospital stay rather than months or years of recovery. The authors were direct about this too, calling for longer studies to see whether the benefits they measured could translate into lasting improvements in heart health over time.
What the study does offer is something genuinely rare in this field: a randomized, controlled comparison, conducted at a major academic medical center, with continuous physiological monitoring rather than self-report alone. That combination is part of why this particular study gets cited again and again by people looking for research-backed information on Reiki.
A Practice Worth Knowing, Wherever You Are in Your Health
I am a Reiki Master Teacher, so I will say plainly that I did not need a Yale study to believe in the value of this practice. But I understand why some people do want the research, and I think it is a good thing to want. Reiki supports the nervous system’s natural ability to restore balance. That is the mechanism this study points toward, and it lines up with what I have watched happen in sessions and in my own daily self-practice over the years.
If you found this research interesting, you may also want to read my post on Reiki and Mental Health: What Mayo Clinic Researchers Found, another early study that asks a careful question.
Curious How Reiki Could Support You?
If you’re curious how a Reiki session could support you, or you’d like to learn a self-practice of your own, I’d love to hear from you.
Book a Session Reach Out with Questions Reiki 4 Well Being • Kandi Mullen, RMT
17+ years in practice. Teaching since 2009. | Pinellas Park, FL | Reiki4WellBeing.com