References: Physical practice pathways

The key studies and reviews behind these pathways – organised by page, so you can see exactly what each claim on the site is based on.

Feuerstein, G. (2001). The Yoga Tradition: Its History, Literature, Philosophy and Practice. Hohm Press. A standard scholarly source for the antiquity of pranayama as a breath discipline within the Vedic tradition.
Russo, M.A., Santarelli, D.M. & O’Rourke, D. (2017). “The physiological effects of slow breathing in the healthy human.” Breathe, 13(4), 298–309. The main review behind this page’s account of how a slow, extended exhalation engages the parasympathetic nervous system.
Yilmaz Balban, M., Neri, E., Kogon, M.M., Weed, L., Nouriani, B., Jo, B., Holl, G., Zeitzer, J.M., Spiegel, D. & Huberman, A.D. (2023). “Brief structured respiration practices enhance mood and reduce physiological arousal.” Cell Reports Medicine, 4(1), 100895. A randomised trial finding exhale-focused breathwork outperformed mindfulness meditation on mood and physiological arousal – supporting evidence for the modern, secular version of the practice described on this page.

Petruzzello, S.J., Landers, D.M., Hatfield, B.D., Kubitz, K.A. & Salazar, W. (1991). “A meta-analysis on the anxiety-reducing effects of acute and chronic exercise: Outcomes and mechanisms.” Sports Medicine, 11(3), 143–182. The classic source behind this page’s claim that a single session reliably lowers anxiety for at least half an hour afterward.
Smits, J.A.J., Berry, A.C., Rosenfield, D., Powers, M.B., Behar, E. & Otto, M.W. (2008). “Reducing anxiety sensitivity with exercise.” Depression and Anxiety, 25(8), 689–699. The main evidence behind this page’s account of exertion as a form of interoceptive exposure – tolerating a pounding heart and breathlessness on purpose to teach the nervous system these sensations aren’t an emergency.
Rebar, A.L., Stanton, R., Geard, D., Short, C., Duncan, M.J. & Vandelanotte, C. (2015). “A meta-meta-analysis of the effect of physical activity on depression and anxiety in non-clinical adult populations.” Health Psychology Review, 9(3), 366–378. Pooled evidence behind this page’s caveat that moderate effort reduces anxiety as well as, or better than, vigorous effort.

Windred, D.P., Burns, A.C., Lane, J.M., Saxena, R., Rutter, M.K., Cain, S.W. & Phillips, A.J.K. (2024). “Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study.” Sleep, 47(1), zsad253. The main source behind this page’s emphasis on a consistent wake time as one of the most powerful levers, even ahead of total sleep duration.
Duffy, J.F. & Czeisler, C.A. (2009). “Effect of light on human circadian physiology.” Sleep Medicine Clinics, 4(2), 165–177. The evidence behind this page’s claim that morning daylight is one of the strongest signals available to the body clock.
Trauer, J.M., Qian, M.Y., Doyle, J.S., Rajaratnam, S.M.W. & Cunnington, D. (2015). “Cognitive Behavioral Therapy for Chronic Insomnia: A Systematic Review and Meta-Analysis.” Annals of Internal Medicine, 163(3), 191–204. The main meta-analysis behind this page’s note that CBT-I is a well-established next step when good sleep habits aren’t enough on their own.