Scientific References: Microhacks – Anti-Stress & Nervous System Relaxation

Scientific Sources

Card Deck "Anti-Stress & Nervous System"

This directory documents the specialist literature on which the cards in this deck are based. It is organized by card topic: For each topic, you will find the corresponding publications with a direct link to the original source, if available. Relevant content statements should be traceable to verifiable, scientifically sound specialist literature. Generally known statements are not referenced here.

The listed sources serve for scientific classification and verifiability. They do not constitute medical advice and do not replace a consultation with a doctor. The citation of a study is not a statement of cure or efficacy.

Status: July 2026 · 262 References

Sympathetic & Parasympathetic Nervous System

Topics: Glucocorticoids and Hippocampus, HPA Axis and Feedback, Allostatic Load, Chronic Stress Activation.

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Body as Stress Mediator (Emotion & Trauma)

Topics: Trauma and body, fascia as a sensory network, body-oriented trauma processing, predictive processing.

  • Van der Kolk, B. A. (2014). The body keeps the score: brain, mind, and body in the healing of trauma. Viking.
  • Schleip, R., et al. (2014). The bodywide fascial network as a sensory organ for haptic perception. Journal of Motor Behavior, 46(3), 191–193.
  • Schleip, R., et al. (Eds.). (2013). Fascia: the tensional network of the human body. Elsevier Health Sciences.
  • Levine, P. A. (2010). In an unspoken voice: how the body releases trauma and restores goodness. North Atlantic Books.
  • Kotler, S., et al. (2026). The body does not keep the score: trauma, predictive coding, and the restoration of metastability. Frontiers in Systems Neuroscience, 20, 1812957. https://doi.org/10.3389/fnsys.2026.1812957
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Physiological Sigh

Topics: Double inhalation and alveoli, "cyclic sighing" and arousal, prolonged exhalation and vagus/baroreflex, breathing variability.

  • Bendixen, H. H., et al. (1964). Pattern of ventilation in young adults. Journal of Applied Physiology, 19(2), 195–198.
  • Balban, M. Y., et al. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 4(1), 100895.
  • Lehrer, P. M., et al. (2014). Heart rate variability biofeedback: how and why does it work? Frontiers in Psychology, 5, 756.
  • Vlemincx, E., et al. (2013). Respiratory variability and sighing: a psychophysiological reset model. Biological Psychology, 93(1), 24–32.
  • Vlemincx, E., et al. (2012). A sigh following sustained attention and mental stress: effects on respiratory variability. Physiology & Behavior, 107(1), 1–6. https://doi.org/10.1016/j.physbeh.2012.05.013
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Natural Diaphragmatic Breathing

Topics: Diaphragm and vagus stimulation, diaphragm in core stabilization, slow breathing and heart rate variability, auricular vagus stimulation.

  • Hamasaki, H. (2020). Effects of diaphragmatic breathing on health: a narrative review. Medicines, 7(10), 65.
  • Bordoni, B., et al. (2013). Anatomic connections of the diaphragm: influence of respiration on the body system. Journal of Multidisciplinary Healthcare, 6, 281–291.
  • Ma, X., et al. (2017). The effect of diaphragmatic breathing on attention, negative affect and stress in healthy adults. Frontiers in Psychology, 8, 874.
  • Ertürk, Ç., et al. (2025). Comparison of the acute effects of auricular vagus nerve stimulation and deep breathing exercise on the autonomic nervous system. Journal of Clinical Medicine, 14(4), 1046.
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Free and Calm Nasal Breathing

Topics: Nasal nitric oxide release, protective function of nasal breathing.

  • Lundberg, J. O. (2008). Nitric oxide and the paranasal sinuses. The Anatomical Record, 291(11), 1479–1484.
  • Mygind, N., et al. (1998). Anatomy, physiology and function of the nasal cavities in health and disease. Advanced Drug Delivery Reviews, 29(1–2), 3–12.
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Breathing Techniques I

Topics: Slow exhalation and respiratory sinus arrhythmia, slow breathing and parasympathetic activity.

  • Laborde, S., et al. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: a systematic review and meta-analysis. Neuroscience & Biobehavioral Reviews, 138, 104711.
  • Zaccaro, A., et al. (2018). How breath-control can change your life: a systematic review on psychophysiological correlates of slow breathing. Frontiers in Human Neuroscience, 12, 353.
  • Bentley, T. G., et al. (2023). Breathing practices for stress and anxiety reduction. Brain Sciences, 13(12), 1612.
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Breathing Techniques II

Topics: Voluntary sympathetic activation (Wim Hof breathing), structured breathing practices, alternate nostril breathing (Nadi Shodhana).

  • Kox, M., et al. (2014). Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proceedings of the National Academy of Sciences, 111(20), 7379–7384.
  • Balban, M. Y., et al. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Reports Medicine, 4(1).
  • Ghiya, S. (2017). Alternate nostril breathing: a systematic review of clinical trials. International Journal of Research in Medical Sciences, 5(8), 3273–3286.
  • Agrawal, N., et al. (2026). Harmony through breath: a review of the physiological and psychological dimensions of Nadi Shodhana. Frontiers in Social Sciences Research, 10–24.
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Building CO₂ Tolerance

Topics: Breath-hold training and breath-hold time, CO₂ sensitivity of respiratory regulation, repeated apnea maneuvers.

  • Bourdas, D. I., et al. (2015). Repeated apneas and hypercapnic ventilatory response before and after apnea training. Aerospace Medicine and Human Performance, 86(1), 27–33.
  • Christoulas, Y., et al. (2025). Acute ergogenic effects of repetitive maximal breath-holding maneuvers on hematological and physiological responses. European Journal of Applied Physiology, 125(3), 739–751.
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Vagal Humming

Topics: Humming (Bhramari) and heart rate variability, humming and nasal nitric oxide release.

  • Trivedi, G., et al. (2023). Humming (simple Bhramari pranayama) as a stress buster. Cureus, 15(4), e37527.
  • Weitzberg, E., et al. (2002). Humming greatly increases nasal nitric oxide. American Journal of Respiratory and Critical Care Medicine, 166(2), 144–145.
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Mouth Movements & Jaw Opening

Topics: Chewing movement and HPA axis, yawning and arousal regulation, masseter muscle activity and stress, tongue movement and salivary stress hormones, chewing and stress.

  • Kubo, K. Y., et al. (2015). Mastication as a stress-coping behavior. BioMed Research International, 2015, 876409.
  • Guggisberg, A. G., et al. (2007). The functional relationship between yawning and vigilance. Behavioural Brain Research, 179(1), 159–166.
  • Angkulmahasuk, S., et al. (2026). Stress-, anxiety-, and gender-related modulation of masseter muscle activity during wakefulness. Journal of Oral Rehabilitation, 53(1), 202–210.
  • Mizuhashi, F., et al. (2020). Salivary secretion and salivary stress hormone level changes induced by tongue rotation exercise. The Journal of Advanced Prosthodontics, 12(4), 204.
  • Tasaka, A., et al. (2018). Psychological stress-relieving effects of chewing. Journal of Prosthodontic Research, 62(1), 50–55.
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Diving Reflex

Topics: Trigeminal-vagal connection and heart rate, cold stimulus to the face and acute stress response, trigeminal nerve stimulation.

  • Khurana, R. K., et al. (1980). Cold face test in the assessment of trigeminal-brainstem-vagal function in humans. Annals of Neurology, 7(2), 144–149.
  • Richer, R., et al. (2022). Vagus activation by Cold Face Test reduces acute psychosocial stress responses. Scientific Reports, 12(1), 19270.
  • Powell, K., et al. (2023). Trigeminal nerve stimulation: a current state-of-the-art review. Bioelectronic Medicine, 9(1), 30.
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Breath-Holding

Topics: Intrathoracic pressure and baroreflex (Valsalva), modified Valsalva maneuver for supraventricular tachycardia.

  • Pstras, L., et al. (2016). The Valsalva manoeuvre: physiology and clinical examples. Acta Physiologica, 217(2), 103–119. https://doi.org/10.1111/apha.12639
  • Appelboam, A., et al. (2015). Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. The Lancet, 386(10005), 1747–1753. https://doi.org/10.1016/S0140-6736(15)61485-4
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Self-Massage I: Face & Forehead

Topics: Trigeminal nerve and nucleus tractus solitarii, deep pressure and mechanoreceptors, C-tactile fibers and affective touch.

  • Mercante, B., et al. (2018). Anatomo-physiologic basis for auricular stimulation. Medical Acupuncture, 30(3), 141–150.
  • Schleip, R. (2003). Fascial plasticity – a new neurobiological explanation: Part 1. Journal of Bodywork and Movement Therapies, 7(1), 11–19.
  • McGlone, F., et al. (2014). Discriminative and affective touch: sensing and feeling. Neuron, 82(4), 737–755.
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Self-Massage II: Neck, Chest & Back