In this article, I share the results of a personal at-home experiment in which I tested the effects of coherent breathing on HRV (Heart Rate Variability), using monitoring tools and a dedicated app.
Further down, you’ll also find a demonstration video documenting the test in real time—a visual comparison between my heart activity in a normal state and during coherent breathing.
The results? Clear, interesting, and perfectly aligned with scientific literature.
What is HRV?
HRV measures the fluctuations in heartbeats over time. Even if we assume a heart rate of 60 beats per minute—one beat per second—in reality, the time between each beat varies slightly. The higher this variability, the more adaptable and resilient our autonomic nervous system is to internal and external stimuli—making it a key indicator of both physical and mental health.
What is Coherent Breathing?
Coherent breathing is a simple yet powerful technique involving a balanced and regular breathing rhythm, where inhalation and exhalation are of equal length—typically around 5.5 seconds each (about 6 breaths per minute). This rhythm helps generate a state of cardiac coherence, in which heart rate and breathing become synchronized, with beneficial effects on overall well-being.
The Data Speaks for Itself
During my presentation on coherent breathing, I shared a chart from the study “A smartphone-based cardiac coherence biofeedback system” by Julien De Jonckheere, which clearly illustrates how coherent breathing impacts HRV. On the left side of the graph, where the subject was breathing normally, the HRV pattern appears irregular. On the right side, where the subject engaged in coherent breathing, the pattern becomes smooth and sinusoidal—evidence of heart-respiration synchronization.
My Personal Experiment
Fascinated by these findings, I decided to replicate the experience at home using a Polar H10 chest strap paired with the Elite HRV app. I first carried out normal daily activities, then followed a 5-5 coherent breathing exercise (5 seconds inhale, 5 seconds exhale) from the web app BR3ATH.
The results were striking: during the coherent breathing phase, my heart rate pattern became periodic—just like in the study.
The video clearly shows what the study’s graph illustrates: during the first minute, my breathing was normal and the HRV trace irregular. In the second minute, as I began coherent breathing, the HRV trace turned into a smooth, regular pattern.
In the still image taken from the video, the HRV periodicity is clearly about 10 seconds, which matches the rhythm of the breathing (one breath every 10 seconds).
A Small Act, A Big Impact
Coherent breathing is an accessible practice with profound effects on health. Just a few minutes a day can help your body enter a state of balance and calm.
The benefits? Greater mental clarity, reduced stress, improved emotional regulation.
Want to try it yourself? Explore the guided 5-5 coherent breathing exercise on BR3ATH