Study Profile
| Authors | Herhaus B., Siepmann T., Kahaly G.J., Conrad R., Petrowski K. |
| Institution | University Medical Center Mainz, Department of Psychosomatic Medicine |
| Journal | Frontiers in Physiology (Open Access, IF ≈ 4) |
| Year | 2022 |
| DOI | 10.3389/fphys.2022.821741 |
| PubMed | PMC8892186 |
| Product | eSense Pulse |
| Design | Prospective intervention study |
| Participants | 26 healthy adults |
What was investigated?
Researchers at the University Medical Center Mainz investigated whether mobile HRV biofeedback training over four weeks can improve autonomic regulation and sleep quality in healthy adults. The key question was whether a practical, app-based biofeedback system can produce the same physiological changes as stationary laboratory equipment.
Methods
26 healthy participants (average age approximately 27 years) completed daily HRV biofeedback training with the eSense Pulse over four weeks. The training sessions followed a resonance frequency protocol at 0.1 Hz (approximately 6 breaths per minute), which is considered the optimal frequency for maximizing heart rate variability.
Measurement timepoints:
- Pre-measurement: Before training onset (baseline)
- Post-measurement: After four weeks of training
Parameters assessed:
- HRV time-domain parameters (SDNN, RMSSD)
- HRV frequency-domain parameters (LF, HF, LF/HF ratio)
- Sleep quality (Pittsburgh Sleep Quality Index, PSQI)
- Autonomic reactivity to stress stimuli
Mindfield product in this study
The researchers used the eSense Pulse by Mindfield Biosystems Ltd., Gronau, Germany (as cited in the paper) for mobile HRV biofeedback training. The sensor measures heart rate variability via an ear clip and transmits data via Bluetooth to the eSense App. Participants trained independently at home with the system.
Results
Autonomic regulation: After four weeks of HRV biofeedback training, participants showed significant changes in autonomic activation. The results indicate improved vagal modulation (parasympathetic activity).
Sleep quality: Participants reported improved subjective sleep quality after the four-week training period, as measured by the Pittsburgh Sleep Quality Index.
Stress reactivity: Autonomic responses to standardized stress stimuli showed changes indicating improved stress regulation.
Significance
This study is significant because it demonstrates that mobile HRV biofeedback with the eSense Pulse — without a laboratory setting or professional guidance — can produce measurable physiological changes. The training protocol at a resonance frequency of 0.1 Hz is an established approach in biofeedback research.
Publication in Frontiers in Physiology (open access, peer-reviewed) makes the results freely accessible to the scientific community. The study was conducted at the University Medical Center Mainz and explicitly mentions Mindfield Biosystems as the manufacturer of the device used.
Original publication in Frontiers in Physiology (Open Access):