Research: What Happens in a Practitioner’s Brain During a Session?
August 19, 2026
Kansha shite · Be grateful
Gratitude, Measured in Blood
Seventy patients with early heart failure. Half were asked to keep a gratitude journal for eight weeks. At the end, the researchers did not ask them how they felt. They took blood.
Kansha shite, be grateful, is the third of the five precepts. It sits at the heart of Reiki self-practice.
The study
Most gratitude research asks people how they feel. This one looked inside them.
Stage B heart failure is the quiet stage. The heart has already changed shape, but symptoms have not arrived yet. It is a window in which the course of the illness can still be altered, which makes it a useful place to test whether a gentle daily practice does anything measurable.
Seventy patients were randomly assigned either to eight weeks of gratitude journalling on top of their usual care, or to usual care alone. Blood was taken at the start and at the end, along with recordings of heart rate variability, a marker of how well the calming branch of the nervous system is working.
- Design
- Randomised pilot trial
- Participants
- 70 patients, mean age 66
- Comparison
- Usual care alone
- Registration
- ClinicalTrials.gov NCT01615094
What they found
Three results
Inflammation went down
The combined inflammatory index fell in the journalling group compared with usual care. This was the strongest result in the study, statistically clear (p = .004) and large in size (η² = 0.21). Inflammation is closely tied to how heart failure progresses.
Gratitude itself increased
The practice did what it was meant to do. Scores on a standard gratitude questionnaire rose in the journalling group (p = .017). Eight weeks of writing shifted something the participants could report on themselves.
The heart responded, but only in the moment
While actually writing, the journalling group showed increased parasympathetic heart rate variability, the calming branch at work (p = .036). At rest, though, there was no difference between the groups. The effect appeared during the practice, not between sessions.
This matters because so little gratitude research uses objective physical measures. Blood does not know which group it was assigned to, and it cannot try to please the researcher.
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Limitations
The authors call this a pilot study, and they are right to.
- The control group did nothing. They received usual care, not an alternative writing task. So attention, routine and expectation cannot be separated out from gratitude itself.
- Nobody was blinded. Participants knew whether they had been asked to journal, and that knowledge alone can shift how people eat, sleep and move.
- Seventy people is small. Small trials produce unstable estimates, and effects often shrink when the study is repeated at scale.
- The resting heart rate variability did not change. The nervous system effect showed up during the writing only, which is a much weaker finding than a lasting shift.
- Eight weeks, then nothing. There was no follow-up, so we cannot know whether the change in inflammation held, faded or grew.
- One narrow group. Older patients with asymptomatic heart failure at a single site. Whether this transfers to healthy people is untested here.
- A combined index, not individual markers. The four markers were pooled into one score, which is statistically sensible but tells us less about what specifically changed.
The research
Redwine, L. S., Henry, B. L., Pung, M. A., Wilson, K., Chinh, K., Knight, B., Jain, S., Rutledge, T., Greenberg, B., Maisel, A., & Mills, P. J. (2016). Pilot randomized study of a gratitude journaling intervention on heart rate variability and inflammatory biomarkers in patients with stage B heart failure. Psychosomatic Medicine, 78(6), 667–676.
This is research into gratitude, not into Reiki, Reiki treatments or Reiki training. It is included here because gratitude is one of the five precepts.
For today only, be grateful.
Eight weeks of it, and something in the blood had quietly moved.
