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Research review

How do meditation, slow breathing, immersive scenes and natural environments relate to stress, HRV and EEG? We reviewed 37 academic studies across 10 topics. Each entry includes the reference, a DOI link and key findings. At the end are 18 of our own HRV pre and post records from 2018.

About this review

We wrote the key findings for each topic. The authors, year, title, journal, volume, issue, pages and DOI of every reference were checked against Crossref and PubMed. Each DOI link opens the original paper on the journal's site, and the evidence type is shown below each reference. Reviewed on 2026-10-08.

HRV basics and measurement standards

International standards and methodological recommendations are available. How to interpret LF/HF is still debated. Further reading: Heart rate variability (HRV) basics.

  1. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). Heart Rate Variability: Standards of Measurement, Physiological Interpretation, and Clinical Use. Circulation, 93(5), 1043-1065. https://doi.org/10.1161/01.cir.93.5.1043 PMID 8598068

    Guideline

    Consensus document from a joint task force of European and North American cardiology and pacing societies that defines time- and frequency-domain HRV measures, recommended recording lengths (5-minute short-term, 24-hour long-term) and the VLF/LF/HF band limits. It also discusses what each measure reflects physiologically and where it applies clinically, and it remains the most widely cited methodological reference. It dates from 1996, predates wearables and ultra-short recordings, and later work has revised how indices such as LF are read.

  2. Billman, G. E. (2013). The LF/HF ratio does not accurately measure cardiac sympatho-vagal balance. Frontiers in Physiology, 4, Article 26. https://doi.org/10.3389/fphys.2013.00026 PMID 23431279

    Theory

    An opinion article examining the physiological basis for treating the LF/HF ratio as a measure of sympatho-vagal balance. The author argues that LF power carries both sympathetic and parasympathetic influence as well as baroreflex and respiratory effects, so the ratio cannot be read as a clean balance index. It is a theoretical critique without new experimental data.

  3. Laborde, S., Mosley, E., & Thayer, J. F. (2017). Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research – Recommendations for Experiment Planning, Data Analysis, and Data Reporting. Frontiers in Psychology, 8, Article 213. https://doi.org/10.3389/fpsyg.2017.00213 PMID 28265249

    Guideline

    Practical recommendations for using HRV as an index of cardiac vagal tone in psychophysiology, covering study design, data processing and reporting. The paper discusses breathing, posture, recording timing, artifact handling and choice of indices, and warns that HRV is easy to collect yet easy to misread. It is methodological guidance rather than new data, and some recommendations are still debated.

  4. Shaffer, F., & Ginsberg, J. P. (2017). An Overview of Heart Rate Variability Metrics and Norms. Frontiers in Public Health, 5, Article 258. https://doi.org/10.3389/fpubh.2017.00258 PMID 29034226

    Narrative review

    A narrative overview of time-domain, frequency-domain and nonlinear HRV indices that also compiles published reference values for healthy, clinical and high-performance groups. The authors stress that recording length, age and sex shift baseline values, so 24-hour, short-term and ultra-short-term figures are not interchangeable. It is a narrative review built on heterogeneous sources, so its reference values should not serve as individual cut-offs.

HRV, stress and the autonomic nervous system

Most studies observe an association between stress and changes in HRV. The link between brain and cardiac regulation rests mainly on theory and correlational evidence.

  1. Thayer, J. F., & Lane, R. D. (2000). A model of neurovisceral integration in emotion regulation and dysregulation. Journal of Affective Disorders, 61(3), 201-216. https://doi.org/10.1016/s0165-0327(00)00338-4 PMID 11163422

    Theory

    Proposes the neurovisceral integration model, which treats autonomic, attentional and emotional regulation as one functional network with prefrontal inhibitory control over subcortical circuits. The authors suggest that when this inhibition breaks down, relative sympathetic activation follows, offering a lens on anxiety and emotional dysregulation. It is a theoretical model that depends on later empirical testing.

  2. Thayer, J. F., Hansen, A. L., Saus-Rose, E., & Johnsen, B. H. (2009). Heart Rate Variability, Prefrontal Neural Function, and Cognitive Performance: The Neurovisceral Integration Perspective on Self-regulation, Adaptation, and Health. Annals of Behavioral Medicine, 37(2), 141-153. https://doi.org/10.1007/s12160-009-9101-z PMID 19424767

    Theory

    Reviews a series of studies from the authors' group linking individual differences in resting HRV to executive function and prefrontal activity, from lab tasks to police-shooting and naval-navigation simulations. Higher HRV went along with better performance on executive tasks, which the authors frame in terms of self-regulation and adaptation. The evidence comes mostly from one group, and the authors call for testing in more populations and settings.

  3. Thayer, J. F., Åhs, F., Fredrikson, M., Sollers, J. J., III, & Wager, T. D. (2012). A meta-analysis of heart rate variability and neuroimaging studies: Implications for heart rate variability as a marker of stress and health. Neuroscience & Biobehavioral Reviews, 36(2), 747-756. https://doi.org/10.1016/j.neubiorev.2011.11.009 PMID 22178086

    Meta-analysis

    A meta-analysis of neuroimaging studies relating HRV to regional cerebral blood flow, identifying regions such as the amygdala and ventromedial prefrontal cortex with consistent associations. The authors use it to extend the neurovisceral integration model, proposing that HRV reflects how strongly top-down appraisal shapes autonomic output. The pooled studies were limited in number and task design, and the findings are correlational.

  4. Kim, H.-G., Cheon, E.-J., Bai, D.-S., Lee, Y. H., & Koo, B.-H. (2018). Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature. Psychiatry Investigation, 15(3), 235-245. https://doi.org/10.30773/pi.2017.08.17 PMID 29486547

    Systematic review

    The authors screened three databases and synthesized 37 human studies that used HRV reactivity as an objective marker of psychological stress. Most reported HRV shifts under stress, most often lower HF and higher LF power, and neuroimaging work tied HRV to stress-appraisal regions such as the ventromedial prefrontal cortex. Although titled a meta-analysis, the abstract mainly reports a qualitative synthesis, and stress-induction and measurement methods varied widely.

Slow breathing, resonance breathing and HRV biofeedback

There are many meta-analyses. Much of the HRV change during practice comes from breathing itself, and psychological outcomes are mostly self-reported.

  1. Lehrer, P. M., & Gevirtz, R. (2014). Heart rate variability biofeedback: how and why does it work?. Frontiers in Psychology, 5, Article 756. https://doi.org/10.3389/fpsyg.2014.00756 PMID 25101026

    Theory

    Examines how HRV biofeedback, which uses breathing near the resonance frequency (about six breaths per minute) to amplify heart-rate oscillations, might work. The authors regard strengthened baroreflex regulation as the best-supported mechanism and also discuss hypotheses involving vagal afferent signals to frontal regions. It is a mechanistic review, and support for the individual mechanisms is uneven.

  2. Goessl, V. C., Curtiss, J. E., & Hofmann, S. G. (2017). The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis. Psychological Medicine, 47(15), 2578-2586. https://doi.org/10.1017/s0033291717001003 PMID 28478782

    Meta-analysis

    Pools 24 studies with 484 participants who completed HRV biofeedback training and looks at self-reported stress and anxiety. Both within-group and between-group effect sizes were large (Hedges' g around 0.8). Outcomes were mostly self-reported, and the authors note the need for more well-controlled trials.

  3. Zaccaro, A., Piarulli, A., Laurino, M., Garbella, E., Menicucci, D., Neri, B., & Gemignani, A. (2018). How Breath-Control Can Change Your Life: A Systematic Review on Psycho-Physiological Correlates of Slow Breathing. Frontiers in Human Neuroscience, 12, Article 353. https://doi.org/10.3389/fnhum.2018.00353 PMID 30245619

    Systematic review

    Following PRISMA, the authors included 15 studies of slow breathing (under 10 breaths per minute) in healthy adults and summarized cardiorespiratory, brain and psychological outcomes. Slow breathing was linked to higher HRV and respiratory sinus arrhythmia, EEG studies mostly showed more alpha and less theta power, and participants reported feeling more relaxed and comfortable. Only 15 heterogeneous studies qualified, and the proposed mechanisms remain hypotheses.

  4. Lehrer, P., Kaur, K., Sharma, A., Shah, K., Huseby, R., Bhavsar, J., Sgobba, P., & Zhang, Y. (2020). Heart Rate Variability Biofeedback Improves Emotional and Physical Health and Performance: A Systematic Review and Meta Analysis. Applied Psychophysiology and Biofeedback, 45(3), 109-129. https://doi.org/10.1007/s10484-020-09466-z PMID 32385728

    Meta-analysis

    A systematic review and meta-analysis of 58 randomized controlled studies of HRV biofeedback across physical and psychological outcomes and athletic or artistic performance. Effects were small to moderate overall, larger for anxiety, depression, anger and performance and smaller for sleep and quality of life, and larger against inactive than active controls. Each application area had few studies, and the authors say specific uses still need confirmation.

  5. Laborde, S., Allen, M. S., Borges, U., Dosseville, F., Hosang, T. J., Iskra, M., Mosley, E., Salvotti, C., Spolverato, L., Zammit, N., & Javelle, F. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: A systematic review and a meta-analysis. Neuroscience & Biobehavioral Reviews, 138, Article 104711. https://doi.org/10.1016/j.neubiorev.2022.104711 PMID 35623448

    Meta-analysis

    A systematic review and meta-analysis of 223 studies on voluntary slow breathing and vagally mediated HRV, split into during practice, right after one session, and after multi-session programs. Vagally mediated HRV was higher at all three time points. Changes during practice are closely tied to the altered breathing rate itself and need to be read with that in mind, and study designs varied considerably.

Meditation, mindfulness and stress

Effect sizes are small to moderate, with no advantage over other active approaches.

  1. Goyal, M., Singh, S., Sibinga, E. M. S., Gould, N. F., Rowland-Seymour, A., Sharma, R., Berger, Z., Sleicher, D., Maron, D. D., Shihab, H. M., Ranasinghe, P. D., Linn, S., Saha, S., Bass, E. B., & Haythornthwaite, J. A. (2014). Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis. JAMA Internal Medicine, 174(3), 357-368. https://doi.org/10.1001/jamainternmed.2013.13018 PMID 24395196

    Meta-analysis

    A systematic review and meta-analysis of 47 randomized trials with active controls (3,515 participants) on meditation programs and stress-related outcomes. Mindfulness programs showed small improvements in anxiety, depression and pain with moderate-strength evidence, weaker evidence for stress and mental-health quality of life, and no advantage over other active treatments such as drugs or exercise. Evidence for positive mood, attention and sleep was insufficient, and the authors call for stronger designs.

  2. Khoury, B., Sharma, M., Rush, S. E., & Fournier, C. (2015). Mindfulness-based stress reduction for healthy individuals: A meta-analysis. Journal of Psychosomatic Research, 78(6), 519-528. https://doi.org/10.1016/j.jpsychores.2015.03.009 PMID 25818837

    Meta-analysis

    A meta-analysis of 29 studies (2,668 participants) on mindfulness-based stress reduction in healthy, non-clinical adults. Stress showed the biggest change, anxiety, depression, quality of life and general distress changed moderately, and burnout changed only slightly, and changes in mindfulness and compassion tracked changes in outcomes. Heterogeneity was high, and which program components matter remains unclear.

EEG basics and brain activity during meditation

Increases in alpha and theta are more common but not consistent. Validation studies of consumer devices have small samples. Further reading: EEG basics.

  1. Klimesch, W. (1999). EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis. Brain Research Reviews, 29(2-3), 169-195. https://doi.org/10.1016/s0165-0173(98)00056-3 PMID 10209231

    Narrative review

    Reviews how alpha and theta oscillations relate to cognitive and memory performance. The author shows that alpha frequency differs considerably between people and recommends defining bands around each person's individual alpha frequency instead of fixed limits; the review also covers changes with age, sleepiness and the transition to sleep, when upper alpha falls and theta rises. It is a theory-driven review and some interpretations are still developing.

  2. Cahn, B. R., & Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, 132(2), 180-211. https://doi.org/10.1037/0033-2909.132.2.180 PMID 16536641

    Narrative review

    Reviews EEG, event-related potential and neuroimaging studies of meditation, separating effects during practice (state) from effects of long-term practice (trait). EEG tends to slow during meditation, with theta and alpha activity related to practice experience, while imaging points to anterior cingulate and dorsolateral prefrontal areas. The authors note that results vary a great deal across meditation styles and methods.

  3. Lomas, T., Ivtzan, I., & Fu, C. H. Y. (2015). A systematic review of the neurophysiology of mindfulness on EEG oscillations. Neuroscience & Biobehavioral Reviews, 57, 401-410. https://doi.org/10.1016/j.neubiorev.2015.09.018 PMID 26441373

    Systematic review

    A systematic review of 56 EEG studies of mindfulness meditation with 1,715 participants, including healthy and psychiatric samples. The most frequent finding was higher alpha and theta power during mindfulness than during eyes-closed rest, though not every study agreed, and beta, delta and gamma showed no consistent pattern. Control conditions and analyses differed widely, and the 'relaxed alertness' reading is the authors' inference.

  4. Urigüen, J. A., & Garcia-Zapirain, B. (2015). EEG artifact removal—state-of-the-art and guidelines. Journal of Neural Engineering, 12(3), Article 031001. https://doi.org/10.1088/1741-2560/12/3/031001 PMID 25834104

    Narrative review

    A methods review that describes the main EEG contaminants, namely ocular, muscle and cardiac artifacts, and compares common removal algorithms. Without prior information, the authors favor independent component analysis, especially second-order approaches such as SOBI, and suggest combining several methods in stages. The comparisons rely largely on simulations and controlled lab recordings, so results with everyday wearables may differ.

  5. Krigolson, O. E., Williams, C. C., Norton, A., Hassall, C. D., & Colino, F. L. (2017). Choosing MUSE: Validation of a Low-Cost, Portable EEG System for ERP Research. Frontiers in Neuroscience, 11, Article 109. https://doi.org/10.3389/fnins.2017.00109 PMID 28344546

    Validation study

    Two experiments tested whether the consumer four-channel MUSE headband can support event-related potential research, using a visual oddball task and a reward-learning task. The expected N200, P300 and reward positivity components could be detected. Validation covered only whether ERP components were observable; with few fixed electrodes, it does not show that spectral values match clinical-grade systems.

  6. Ratti, E., Waninger, S., Berka, C., Ruffini, G., & Verma, A. (2017). Comparison of Medical and Consumer Wireless EEG Systems for Use in Clinical Trials. Frontiers in Human Neuroscience, 11, Article 398. https://doi.org/10.3389/fnhum.2017.00398 PMID 28824402

    Validation study

    Four wireless EEG systems, the consumer Muse and Mindwave and the medical-grade B-Alert and Enobio, were compared in five healthy adults over two visits during eyes-open and eyes-closed rest, using the shared Fp1 electrode for power spectra and test-retest reliability. All four recorded usable data, but Muse showed broadly higher power and the most test-retest variation, consumer devices were more affected by blinks and frontal muscle activity, and the medical systems gave clearly better quality and reliability. Only five people and one frontal electrode were compared, and some authors were affiliated with makers of the medical-grade systems tested.

VR and immersive relaxation

Most findings are short-term, with few randomized controlled trials or long-term follow-ups. Most studies use 360-degree video or prerecorded natural scenery, which differs from real-time 3D scenes.

  1. Anderson, A. P., Mayer, M. D., Fellows, A. M., Cowan, D. R., Hegel, M. T., & Buckey, J. C. (2017). Relaxation with Immersive Natural Scenes Presented Using Virtual Reality. Aerospace Medicine and Human Performance, 88(6), 520-526. https://doi.org/10.3357/amhp.4747.2017 PMID 28539139

    Experimental study

    Eighteen adults did a mental-arithmetic stressor before each of three 15-minute 360-degree scenes (indoor control, rural Ireland, beaches) while electrodermal activity and HRV were recorded. Electrodermal activity fell further and negative affect dropped after the natural scenes but not after the control scene, and each person's preferred scene scored better on mood and scene quality. The sample was small, each scene was seen once, and the work was framed around isolated, confined settings.

  2. Browning, M. H. E. M., Mimnaugh, K. J., van Riper, C. J., Laurent, H. K., & LaValle, S. M. (2020). Can Simulated Nature Support Mental Health? Comparing Short, Single-Doses of 360-Degree Nature Videos in Virtual Reality With the Outdoors. Frontiers in Psychology, 10, Article 2667. https://doi.org/10.3389/fpsyg.2019.02667 PMID 32010003

    Experimental study

    Healthy undergraduates spent 6 minutes outdoors in nature, watched a 6-minute 360-degree VR video filmed at the same spot, or stayed in an indoor setting without nature, with skin conductance, perceived restorativeness and mood measured. Both nature conditions felt more restorative than the indoor setting, but positive mood rose only outdoors and stayed level in VR. Exposures were single and brief, participants were students, and 360-degree video differs from interactive real-time 3D scenes.

  3. Riches, S., Azevedo, L., Bird, L., Pisani, S., & Valmaggia, L. (2021). Virtual reality relaxation for the general population: a systematic review. Social Psychiatry and Psychiatric Epidemiology, 56(10), 1707-1727. https://doi.org/10.1007/s00127-021-02110-z PMID 34120220

    Systematic review

    A systematic review of 19 studies (1,278 participants, 13 with a control group) that used head-mounted displays to present relaxing virtual environments to the general population. Most used natural audiovisual scenes, and together they suggest VR relaxation is feasible, well accepted and linked to short-term gains in relaxation and lower stress. Quality ratings split roughly evenly across strong, moderate and weak, randomized and long-term studies were scarce, and the authors urge caution.

Natural environments and stress recovery

Theory and observational studies dominate. Empirical support for attention restoration theory is limited.

  1. Ulrich, R. S., Simons, R. F., Losito, B. D., Fiorito, E., Miles, M. A., & Zelson, M. (1991). Stress recovery during exposure to natural and urban environments. Journal of Environmental Psychology, 11(3), 201-230. https://doi.org/10.1016/s0272-4944(05)80184-7

    Experimental study

    A classic laboratory experiment in which participants watched a stressful film and then viewed videotapes of natural or urban settings while cardiac activity, muscle tension, skin conductance and self-rated affect were recorded. Recovery was faster and more complete with natural scenes, which the authors used to support their stress reduction view of nature. Settings were presented on video in a single lab session.

  2. Kaplan, S. (1995). The restorative benefits of nature: Toward an integrative framework. Journal of Environmental Psychology, 15(3), 169-182. https://doi.org/10.1016/0272-4944(95)90001-2

    Theory

    A theoretical paper offering an integrative framework that ties directed-attention fatigue from sustained concentration to stress recovery. It argues that settings offering being away, extent, fascination and compatibility, natural ones in particular, help attention recover. It is a conceptual framework that relies on later empirical tests.

  3. Ohly, H., White, M. P., Wheeler, B. W., Bethel, A., Ukoumunne, O. C., Nikolaou, V., & Garside, R. (2016). Attention Restoration Theory: A systematic review of the attention restoration potential of exposure to natural environments. Journal of Toxicology and Environmental Health, Part B, 19(7), 305-343. https://doi.org/10.1080/10937404.2016.1196155 PMID 27668460

    Meta-analysis

    A systematic review of 31 studies comparing natural and non-natural settings on objective attention tests, with meta-analyses where data allowed. Only 3 of 13 pooled analyses (digit span forward and backward, Trail Making Test B) showed significant benefits; the others did not. Few studies, small samples and varied outcomes leave open which aspects of attention nature affects.

  4. Twohig-Bennett, C., & Jones, A. (2018). The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes. Environmental Research, 166, 628-637. https://doi.org/10.1016/j.envres.2018.06.030 PMID 29982151

    Meta-analysis

    A systematic review and meta-analysis of 103 observational and 40 interventional studies covering about 100 health outcomes in relation to greenspace exposure. More exposure was associated with lower salivary cortisol, heart rate and diastolic blood pressure, an HRV pattern of higher HF and lower LF, and lower risk of several diseases. The evidence is mostly observational, of mixed quality and highly heterogeneous, so it does not support causal claims.

Pre-sleep relaxation, breathing and sleep

Mindfulness interventions show improvement compared with nonspecific controls and no difference compared with evidence-based sleep interventions. Breathing studies have very small samples.

  1. Ong, J. C., Manber, R., Segal, Z., Xia, Y., Shapiro, S., & Wyatt, J. K. (2014). A Randomized Controlled Trial of Mindfulness Meditation for Chronic Insomnia. Sleep, 37(9), 1553-1563. https://doi.org/10.5665/sleep.4010 PMID 25142566

    Randomized controlled trial

    A three-arm randomized controlled trial in which 54 adults with chronic insomnia received MBSR, mindfulness-based therapy for insomnia, or 8 weeks of self-monitoring. Both meditation arms showed larger drops than self-monitoring in diary-based total wake time, pre-sleep arousal and insomnia severity, and by 6 months the insomnia-specific program had reduced insomnia severity more than MBSR. It was a small single-site trial with mostly self-reported outcomes and a control arm not matched for contact time.

  2. Tsai, H. J., Kuo, T. B. J., Lee, G.-S., & Yang, C. C. H. (2015). Efficacy of paced breathing for insomnia: Enhances vagal activity and improves sleep quality. Psychophysiology, 52(3), 388-396. https://doi.org/10.1111/psyp.12333 PMID 25234581

    Experimental study

    A Taiwanese study comparing HRV in 14 self-reported insomniacs and 14 good sleepers while breathing at a slow 0.1 Hz and at 0.2 Hz, with night-time sleep recorded by polysomnography. The insomnia group had lower HF power, total HRV power rose during slow breathing, and on nights after 20 minutes of slow breathing before bed they fell asleep sooner, woke less and slept more efficiently. The sample was very small, groups were not randomized and practice was brief.

  3. Rusch, H. L., Rosario, M., Levison, L. M., Olivera, A., Livingston, W. S., Wu, T., & Gill, J. M. (2019). The effect of mindfulness meditation on sleep quality: a systematic review and meta‐analysis of randomized controlled trials. Annals of the New York Academy of Sciences, 1445(1), 5-16. https://doi.org/10.1111/nyas.13996 PMID 30575050

    Meta-analysis

    A systematic review and meta-analysis of 18 randomized controlled trials (1,654 participants) on mindfulness meditation and sleep quality, analysed separately against specific active controls such as evidence-based sleep treatments and against non-specific active controls. Mindfulness did better than non-specific controls after the intervention and at follow-up (moderate-strength evidence) but did not differ from specific sleep treatments (low-strength evidence). The authors present the findings as preliminary.

Validity of wearable HRV measurement

Reliability is better at rest and drops during physical activity. Validation studies of optical sensing are fewer.

  1. Schäfer, A., & Vagedes, J. (2013). How accurate is pulse rate variability as an estimate of heart rate variability? A review on studies comparing photoplethysmographic technology with an electrocardiogram. International Journal of Cardiology, 166(1), 15-29. https://doi.org/10.1016/j.ijcard.2012.03.119 PMID 22809539

    Narrative review

    Reviews studies comparing pulse rate variability (PRV) derived from pulse waves such as optical PPG with ECG-based HRV. At rest PRV was generally accurate enough, though short-term variability tended to be overestimated, likely reflecting respiratory-cardiovascular coupling; physical activity and some mental stressors often worsened agreement considerably. Differences in setups and analysis methods prevented firm quantitative conclusions.

  2. Georgiou, K., Larentzakis, A. V., Khamis, N. N., Alsuhaibani, G. I., Alaska, Y. A., & Giallafos, E. J. (2018). Can Wearable Devices Accurately Measure Heart Rate Variability? A Systematic Review. Folia Medica, 60(1), 7-20. https://doi.org/10.2478/folmed-2018-0012 PMID 29668452

    Systematic review

    A systematic review of 18 studies on how accurately wearables measure HRV, 16 with ECG-based and 2 with photoplethysmography (PPG) sensors. Agreement with standard ECG ranged from very good to excellent at rest but declined as exercise intensity rose. Methods and samples varied widely, and PPG evidence was thin.

  3. Gilgen-Ammann, R., Schweizer, T., & Wyss, T. (2019). RR interval signal quality of a heart rate monitor and an ECG Holter at rest and during exercise. European Journal of Applied Physiology, 119(7), 1525-1532. https://doi.org/10.1007/s00421-019-04142-5 PMID 31004219

    Validation study

    Ten healthy adults wore a Holter ECG and a Polar H10 chest strap at the same time during five activities from low to high intensity, and RR-interval accuracy was judged against visual review of the raw ECG. Overall signal quality was 94.6% for the Holter and 99.6% for the chest strap, which stayed near 99% even at high intensity. Only 10 people took part and only RR-interval detection, not the derived HRV indices, was assessed.

Workplace wellbeing interventions

Psychological outcomes show small to moderate improvement. Data on work performance, physiological measures and long-term follow-up are insufficient.

  1. Richardson, K. M., & Rothstein, H. R. (2008). Effects of occupational stress management intervention programs: A meta-analysis. Journal of Occupational Health Psychology, 13(1), 69-93. https://doi.org/10.1037/1076-8998.13.1.69 PMID 18211170

    Meta-analysis

    A meta-analysis of 36 workplace stress-management studies covering 55 interventions and 2,847 participants. The overall effect was medium to large (Cohen's d around 0.53), cognitive-behavioral programs had the largest effects, relaxation was the most common approach, and organization-level interventions were rare. Outcomes were mostly psychological, with few physiological or organizational measures.

  2. Bartlett, L., Martin, A., Neil, A. L., Memish, K., Otahal, P., Kilpatrick, M., & Sanderson, K. (2019). A systematic review and meta-analysis of workplace mindfulness training randomized controlled trials. Journal of Occupational Health Psychology, 24(1), 108-126. https://doi.org/10.1037/ocp0000146 PMID 30714811

    Meta-analysis

    A meta-analysis of 23 randomized controlled trials of mindfulness training delivered at work. Training was associated with improvements in mindfulness, stress, anxiety, psychological distress, well-being and sleep, with small to moderate effect sizes. Burnout, depression and work performance could not be judged because of mixed results, publication bias or too little data.

  3. Vonderlin, R., Biermann, M., Bohus, M., & Lyssenko, L. (2020). Mindfulness-Based Programs in the Workplace: a Meta-Analysis of Randomized Controlled Trials. Mindfulness, 11(7), 1579-1598. https://doi.org/10.1007/s12671-020-01328-3

    Meta-analysis

    A meta-analysis of 56 randomized controlled studies of workplace mindfulness programs (2,689 participants, 2,472 controls). Programs were associated with less stress, burnout, distress and somatic complaints and with greater mindfulness, compassion, job satisfaction and well-being, with small to large effect sizes that held at follow-ups of up to 12 weeks. Heterogeneity was not consistently explained by program or participant features, and data on engagement, productivity and longer follow-up were limited.

Research and product history

The guided scripts and scene designs in Mandala Hub have been carried from the 2018 video version to today's real-time 3D. Each stage below lists what was done, what was recorded and the limits.

2018: Ministry of Economic Affairs health promotion service program

Big Heart Digital Culture took part in the 2018 business model coaching under the Industrial Development Bureau's Health Promotion Service Industry Development Program (coaching organization: Commerce Development Research Institute), with a project titled "An oasis for office workers: a relaxation and massage rest station service model".

  • Guided scripts were based on mindfulness-based stress reduction (MBSR) and body scan; following the review committee's comments, the content was checked by a psychiatrist.
  • Trials ran at a wellness retreat, a counseling practice and an office; four sessions reached more than 90 attendances, including psychiatrists, clinical and counseling psychologists and social workers.
  • Participants filled in a self-report mood questionnaire (designed by the team) before and after use; 106 valid questionnaires were returned.
  • Changes made from feedback: a screen stand replaced the VR headset, the image was dimmed, and the script tells people they can close their eyes and just listen.
  • At 蛹之生心理諮商所 (a counseling practice in Taichung), HRV was measured once before and once after a relaxation session with a handheld analyzer, giving the 18 pairs below.
Analyzer reports side by side, pre and post: autonomic age changes from 79 or older to 60 to 65
Participant one, pre (left) and post (right), about 40 minutes apart. The autonomic age on the report changed from "79 or older" to "60 to 65", and SDNN from 10.7 to 22.0 ms. Personal details have been removed. The reports are in Chinese.
Analyzer index charts side by side, pre and post: autonomic age changes from 35 to 40 to under 20
Participant two, pre (left) and post (right). The autonomic age on the report changed from "35 to 40" to "under 20", and SDNN from 51.6 to 62.6 ms.

Direction of change across 18 pairs

MeasurePost compared with preMean change
Heart rateLower in 13, higher in 3, unchanged in 2−4.0 beats per minute
Autonomic age on the reportLower age band in 11, higher in 2; the other 5 were at the report's floor ("under 20") both timesAbout −7.9 years (band midpoints)
Overall autonomic function (ANS)Higher in 13, lower in 4+0.72
SDNNHigher in 10, lower in 8+13.2 ms

Lower heart rate and a lower autonomic age band moved in a consistent direction across the 18 pairs (two-sided sign test, p about 0.02). SDNN and the parasympathetic index varied from person to person. The pre and post reports in Mandala Hub today were redesigned from these records, including the measurement method and the age norms.

2021: research with a counseling practice

Hui-Lan Tan (譚慧蘭), director of 蛹之生心理諮商所 and a doctoral student in the Department of Guidance and Counseling at National Changhua University of Education, worked with Big Heart Digital Culture on 3D immersive video for pre-sleep relaxation and employee assistance programs (EAP). Cheng-Hsien Yang (楊政憲), general manager of Big Heart Digital Culture, produced the 3D scenes and video.

  • Five experts, including physicians, psychologists and mindfulness instructors, reviewed the scripts in a Delphi process until all agreed.
  • Seven 3D video segments were produced from the scripts, with recorded guidance and background music.
  • The study was reviewed by the National Cheng Kung University Human Research Ethics Committee (case 110-465). According to the closing report, 30 adults aged 24 to 45 who reported difficulty falling asleep or poor sleep quality took part (15 men, 15 women), all with signed consent; people with diagnosed sleep apnea or restless legs syndrome, or in sleep-related treatment, were excluded.
  • HRV was measured before and after viewing. The closing report records a rise in the parasympathetic index (VAG) after viewing; it does not include statistical values.

The team presented an abstract at the 2021 Annual Conference of the Taiwan Guidance and Counseling Association, "Challenges and Empowerment in Changing Times" (23 October 2021, National Changhua University of Education):

譚慧蘭、楊政憲、李雅君 [Tan, H.-L., Yang, C.-H., & Lee, Y.-C.] (2021, October). [Development of immersive 3D video for sleep improvement in clients with sleep disorders and corporate EAP applications] [Abstract]. 2021 Annual Conference of the Taiwan Guidance and Counseling Association, National Changhua University of Education, Changhua, Taiwan. (Original title in Chinese)

Limits of this study

  • Only two measurements, before and after viewing; no continuous recording and no control group.
  • The closing report does not include statistical test values.
  • The HRV device and video format differ from today's Mandala Hub.

Today: the same scripts and scenes in real-time 3D

The current 3D scenes were rebuilt from the original video segments and keep the same guided scripts, now in real-time 3D with separate main and branch paths, and continuous HRV armband and EEG recording. The segments with clearer changes in the 2021 study all have a counterpart today:

2021 video segmentCurrent 3D scene
Basic relaxation with a sense of weightlessnessWeightless floating on a lounge chair
Guidance walking down a staircaseSteps into deeper meditation
Non-logical language guidanceFloating pudding staircase
Pre-sleep focus with weightlessnessWeightless drifting awareness
Repeated pre-sleep music under a panoramic starry skyInterstellar hum

Figures in reports come from each session's own measurements and are calculated separately from the early studies above.

Found an error or know a study we should add

If you find a mistake in a reference or key finding, or know of research worth adding, please email asupeduer@ibigheart.com. We will verify it, update the page and change its updated date.