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synappro breathe was developed with reference to published research on mindful breathing, autonomic regulation, stress, anxiety, cardiovascular function and related breathing techniques. Below is a list of the studies and sources referenced throughout the app.

relax · 4-7-8

1. Vierra J, Boonla O, Prasertsri P. Effects of sleep deprivation and 4-7-8 breathing control on heart rate variability, blood pressure, blood glucose, and endothelial function in healthy young adults. Physiol Rep. 2022 Jul;10(13):e15389.
2. Nielsen C, Katz S, Parker M, et al. A student-driven mindfulness curriculum for first-year osteopathic medical students: a pilot study. J Osteopath Med. 2023 Jul 12;123(10):485-492.
3. Aktaş GK, İlgin VE. The effect of deep breathing exercise and 4-7-8 breathing techniques applied to patients after bariatric surgery on anxiety and quality of life. Obesity Surgery. 2023;33(3):920-929.

focus · box breathing

4. Grossman D, Christensen LW. On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace. 3rd ed. Belleville, IL: PPCT Research Publications; 2008.
5. Röttger S, Theobald DA, Abendroth J, et al. The effectiveness of combat tactical breathing as compared with prolonged exhalation. Appl Psychophysiol Biofeedback. 2021;46:19-28.
6. Bouchard S, Bernier F, Boivin E, Morin B, Robillard G. Using biofeedback while immersed in a stressful videogame increases the effectiveness of stress management skills in soldiers. PLoS One. 2012;7(4):e36169.

energise · longer breath holds

7. Kox M, van Eijk LT, Zwaag J, et al. Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proc Natl Acad Sci U S A. 2014 May 20;111(20):7379-84.

general breathing research

8. Russo MA, Santarelli DM, O'Rourke D. The physiological effects of slow breathing in the healthy human. Breathe. 2017;13(4):298-309.
9. Morgan SP, Lengacher CA, Seo Y. A systematic review of breathing exercise interventions: an integrative complementary approach for anxiety and stress in adult populations. Journal of Holistic Nursing. 2024;42(3):215-230.
10. Jerath R, Edry JW, Barnes VA, Jerath V. Physiology of long pranayamic breathing: neural respiratory elements may provide a mechanism that explains how slow deep breathing shifts the autonomic nervous system. Medical Hypotheses. 2006;67(3):566-571.

alternate nostril breathing

11. Nivethitha L, Mooventhan A, Manjunath NK. Effects of various Prāṇāyāma on cardiovascular and autonomic variables. Ancient Science of Life. 2016;36(2):72-77.
12. Nam TG, Jeong HI, Kim KH, Jang I. Effectiveness of alternative nostril breathing on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Complementary Medicine Research. 2023;31(5):449-459.

diaphragmatic breathing

13. Hopper SI, Murray SL, Ferrara LR, Singleton JK. Effectiveness of diaphragmatic breathing for reducing physiological and psychological stress in adults: a quantitative systematic review. JBI Database of Systematic Reviews and Implementation Reports. 2019;17(9):1855-1876.

sighing

14. Vlemincx E, Van Diest I, Van den Bergh O. A sigh of relief or a sigh to relieve: the psychological and physiological relief effect of deep breaths. Physiology & Behavior. 2016;165:127-135.
15. Vlemincx E, et al. Take a deep breath: the relief effect of spontaneous and instructed sighs. Physiology & Behavior. 2010;101(1):67-73.