--- The Oxytocin Effect
The American sociologist Ira Reiss once compared the stages of romantic love to a turning wheel. His Wheel Theory of Love dates back several decades, but it was one of the first models to map the full arc of how two strangers meet, court, deepen their relationship, and ultimately choose each other as partners. According to Reiss, as a couple moves toward real intimacy, they pass through four cyclical, interlocking stages — the spokes of the wheel: rapport, self-revelation, mutual dependency, and personality need fulfillment. First, the couple discovers shared ground and builds rapport. Then, seeking a deeper connection, they move into self-revelation, each opening up to the other. As they come to know each other more fully, dependency grows, until they reach the point of fulfilling each other's core needs and desires. Reiss believed every love relationship follows this progression.
Looking back at my own life, I can trace the wheel's rotations with surprising accuracy — from the initial curiosity that drew me toward a woman I had never met, through falling in love, to the steady interdependence of marriage. "For the one carelessly cast aside — you, the only one who wept for me — I want to lean against those broad shoulders. Don't wake me from that dream." Those are lyrics from All I Know Is Love, the signature song of the beloved Korean singer Sim Su-bong. In an interview, she once said that she grew up without a father and had never known a man's love — her husband was the first person to give her that. Human beings stake everything on love. They make sacrifices for it that defy rational calculation. Love is our greatest vulnerability and, at the same time, our greatest strength. It is the one capacity God placed in the human heart. That is why the great Sufi poet Rumi wrote: "Love is the emblem of God's infinite beauty."
Love, That Mighty Force
In 1942, Karl A. Menninger wrote in Love Against Hate: "Science is merely our servant. We use it to forge guns, and we use it to compound fever remedies. We use it to build bridges, and we use it to blow them up." He went on to say that when a psychologist speaks of science, the words fall like "a voice crying in the wilderness." His argument was bold for its time: because so many of the world's diseases start in the mind, the job of psychology and psychoanalysis is to heal the mind where those diseases begin. And the medicine that heals the mind, he declared, is love.
In the same book, Menninger quoted Freud, who reportedly said near the end of his life: "The idea that love can cure hatred is an entirely new perspective. And it seems no one has yet dared to put it into practice."[22-1]
Menninger published those words while the Second World War was raging and nations were competing to build ever more efficient ways to kill. Even allowing for the brutality of the era, his insight — that illness can grow from personality, thought patterns, and habitual attitudes — feels both profound and strangely ahead of its time. He pushed even further, essentially making a claim that would not sound out of place in scripture — love heals all sorrow — but framing it in the language of science. Could the wars between nations, he wondered, be driven not by grand geopolitical forces but by the vanity, insecurity, and wounded pride of individual leaders? Those wars devoured countless lives. Someone lost a son. Someone lost a husband. Someone lost a father. Someone lost a mother. Countless survivors lost limbs and lived out their years with disabilities; far more carried invisible scars of trauma that never fully healed. Menninger prescribed love as the remedy for all of it. Could it be that he sensed the power of oxytocin long before anyone knew how to measure it?
Love Through the Lens of Oxytocin
Menninger was, of course, talking about how love heals psychological wounds and, at its deepest, mental illness itself. And oxytocin does exactly what he described. It alleviates PTSD. It repairs the damage caused by chronic stress. It resolves the psychological problems born of loneliness. It makes people more likable and more optimistic. It mends broken relationships by rebuilding trust. When you consider that stress is a documented cause of stomach ulcers, hypertension, cardiovascular disease, diabetes, and cancer, oxytocin starts to look a lot like a universal remedy.
In South Korea, suicide is the number one cause of death for people in their teens through their thirties. When you realize that oxytocin could, in principle, address every one of the country's top five causes of death, the implications are staggering. Jesus said, "Love your neighbor as yourself." But to love our neighbors, we have to love our own bodies first. The finding that people who attempt suicide have significantly lower circulating oxytocin than those who do not — what does that tell us about a country that leads the developed world in suicide rates?[22-2]
I have spent my entire career as a researcher trying to prove a deceptively simple idea: exercise is medicine. For decades, I studied how to help more people get healthier and live better through physical movement. Along the way, I encountered oxytocin — and the more I learned, the more I explored its effects on health, the more I felt myself being pulled beyond the familiar motto toward something deeper and more fundamental.
Not just exercise is medicine.
Love is medicine.
Love fiercely. Love with everything you have. Love as though your life depends on it — because it does.
References
Chapter 17
[17-1]: Friedman, M. Type A Behavior and Your Heart. Ballantine Books, 1974. See also: Friedman M, Rosenman RH. Type A Behavior Pattern: its association with coronary heart disease. Ann Clin Res. 1971;3(6):300-312.
[17-2]: Alley J, Diamond LM, Lipschitz DL, Grewen K. Associations between oxytocin and cortisol reactivity and recovery in response to psychological stress and sexual arousal. Psychoneuroendocrinology. 2019;106:47-56. See also: Le Dorze C, et al. Emotional remodeling with oxytocin durably rescues trauma-induced behavioral and neuro-morphological changes in rats. Transl Psychiatry. 2020;10(1):27; Blume A, et al. Oxytocin reduces anxiety via ERK1/2 activation. Eur J Neurosci. 2008;27(8):1947-1956.
[17-3]: Lang RE, et al. Oxytocin unlike vasopressin is a stress hormone in the rat. Neuroendocrinology. 1983;37(4):314-316. See also: Nishioka T, et al. Stress increases oxytocin release within the hypothalamic paraventricular nucleus. Brain Res. 1998;781(1-2):57-61; Seltzer LJ, et al. Stress-induced elevation of oxytocin in maltreated children. Child Dev. 2014;85(2):501-512; Petersson M, et al. Oxytocin decreases carrageenan-induced inflammation in rats. Peptides. 2001;22(9):1479-1484.
[17-4]: Light KC, Grewen KM, Amico JA. More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. Biol Psychol. 2005;69(1):5-21. See also: Faghihi M, et al. The role of nitric oxide, reactive oxygen species, and protein kinase C in oxytocin-induced cardioprotection in ischemic rat heart. Peptides. 2012;37(2):314-319; Dyavanapalli J, et al. Activation of Oxytocin Neurons Improves Cardiac Function in a Pressure-Overload Model of Heart Failure. JACC Basic Transl Sci. 2020;5(5):484-497.
Chapter 18
[18-1]: Duckworth WC, Jallepalli P, Solomon SS. Glucose intolerance in spinal cord injury. Arch Phys Med Rehabil. 1983;64(3):107-110. See also: Jeon JY, et al. Reduced plasma glucose and leptin after 12 weeks of functional electrical stimulation-rowing exercise training in spinal cord injury patients. Arch Phys Med Rehabil. 2010;91(12):1957-1959.
[18-2]: Jeon JY, Steadward RD, Wheeler GD, Bell G, McCargar L, Harber V. Intact sympathetic nervous system is required for leptin effects on resting metabolic rate in people with spinal cord injury. J Clin Endocrinol Metab. 2003;88(1):402-407. See also: Jeon JY, et al. MCH-/- mice are resistant to aging-associated increases in body weight and insulin resistance. Diabetes. 2006;55(2):428-434.
[18-3]: Leng G, et al. Oxytocin and appetite. Prog Brain Res. 2008;170:137-151. See also: Verbalis JG, et al. Oxytocin secretion in response to cholecystokinin and food: differentiation of nausea from satiety. Science. 1986;232(4756):1417-1419.
[18-4]: Danziger S, Levav J, Avnaim-Pesso L. Extraneous factors in judicial decisions. Proc Natl Acad Sci U S A. 2011;108(17):6889-6892.
[18-5]: Lawson EA, et al. Oxytocin reduces caloric intake in men. Obesity (Silver Spring). 2015;23(5):950-956.
[18-6]: Liu J, Tong J, Blevins JE. Oxytocin as an Anti-obesity Treatment. Front Neurosci. 2021;15:743546.
Chapter 19
[19-1]: Xu S, et al. Oxytocin inhibited stress-induced visceral hypersensitivity, enteric glial cells activation, and release of proinflammatory cytokines in maternal separated rats. Eur J Pharmacol. 2018;818:578-584.
[19-2]: Schneider KM, et al. The enteric nervous system relays psychological stress to intestinal inflammation. Cell. 2023;186(13):2823-2838.
[19-3]: Louvel D, et al. Oxytocin increases thresholds of colonic visceral perception in patients with irritable bowel syndrome. Gut. 1996;39(5):741-747. See also: Tang Y, et al. Oxytocin system alleviates intestinal inflammation by regulating macrophages polarization in experimental colitis. Clin Sci (Lond). 2019;133(18):1977-1992; Yu Y, et al. Oxytocin suppresses epithelial cell-derived cytokines production and alleviates intestinal inflammation in food allergy. Biochem Pharmacol. 2022;195:114867.
Chapter 20
[20-1]: Kroenke CH, et al. Social networks, social support, and burden in relationships, and mortality after breast cancer diagnosis in the LACE study. Breast Cancer Res Treat. 2013;137(1):261-271. See also: Martinez ME, et al. Prognostic significance of marital status in breast cancer survival. PLoS One. 2017;12(5):e0175515; Pinquart M, Duberstein PR. Associations of social networks with cancer mortality: a meta-analysis. Crit Rev Oncol Hematol. 2010;75(2):122-137.
[20-2]: Naderi A, et al. Persistent effects of pair bonding in lung cancer cell growth in monogamous Peromyscus californicus. Elife. 2021;10. See also: Ford CL, Young LJ. Harnessing the healing power of love. Trends Mol Med. 2021;27(9):833-834.
[20-3]: Cassoni P, et al. Oxytocin Inhibits Proliferation of Human Breast-Cancer Cell-Lines. Virchows Arch. 1994;425(5):467-472. See also: Cassoni P, et al. Oxytocin inhibits the proliferation of MDA-MB231 human breast-cancer cells via cyclic adenosine monophosphate and protein kinase A. Int J Cancer. 1997;72(2):340-344; Khori V, et al. Oxytocin effects on the inhibition of the NF-kB/miR195 pathway in mice breast cancer. Peptides. 2018;107:54-60.
[20-4]: Uvnas-Moberg K, et al. Breastfeeding: physiological, endocrine and behavioural adaptations caused by oxytocin and local neurogenic activity in the nipple and mammary gland. Acta Paediatr. 1996;85(5):525-530. See also: Pan S, et al. Stimulation of hypothalamic oxytocin neurons suppresses colorectal cancer progression in mice. Elife. 2021;10; Mankarious A, et al. The pro-social neurohormone oxytocin reverses the actions of the stress hormone cortisol in human ovarian carcinoma cells in vitro. Int J Oncol. 2016;48(5):1805-1814.
Chapter 21
[21-1]: Claude Steiner. Emotional Literacy: Intelligence with a Heart. Personhood Press, 2003.
[21-2]: Karla McLaren. The Language of Emotions (Korean edition: Gamjeong Ilgi, trans. Jeon Hye-young. Jisik-ui Sup, 2014).
[21-3]: Vellante M, Baron-Cohen S, et al. The "Reading the Mind in the Eyes" test: Systematic review of psychometric properties and a validation study in Italy. Cogn Neuropsychiatry. 2013;18(4):326-354. See also: Baron-Cohen S, et al. The "Reading the Mind in the Eyes" Test: Complete Absence of Typical Sex Difference in ~400 Men and Women with Autism. PLoS One. 2015;10(8).
[21-4]: Domes G, et al. Effects of Intranasal Oxytocin on the Neural Basis of Face Processing in Autism Spectrum Disorder. Biol Psychiatry. 2013;74(3):164-171. See also: Guastella AJ, et al. Intranasal Oxytocin Improves Emotion Recognition for Youth with Autism Spectrum Disorders. Biol Psychiatry. 2010;67(7):692-694.
[21-5]: Ford CL, Young LJ. Refining oxytocin therapy for autism: context is key. Nat Rev Neurol. 2022;18(2):67-68.
Chapter 22
[22-1]: Karl Menninger. Love Against Hate (Korean edition: Sarang-gwa Mium, trans. Lee Yong-ho. Baekjo Publishing, 1986).
[22-2]: Warrener CD, et al. The role of oxytocin signaling in depression and suicidality in returning war veterans. Psychoneuroendocrinology. 2021;126:105085. See also: Sharma SR, et al. What's Love Got to do with it: Role of oxytocin in trauma, attachment and resilience. Pharmacol Ther. 2020;214:107602.