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Understanding how breathwork, specifically the Sudarshan Kriya Yoga – RP (also known as SKY Breath and related practices) regulates stress requires a look into its effects on the body’s hormonal and neuroendocrine systems. In addition to directly interacting with the sympathetic nervous system (which activates the body’s fight-or-flight response) and the opposite parasympathetic nervous system (slowing the body down, restoring calm, and supporting recovery, healing, and long-term resilience) as discussed in a previous post, breathing is also tied to other hormone-regulating systems.[1]
Also key to this process is the hypothalamic–pituitary–adrenal (HPA) axis, which governs the release of stress hormones such as cortisol and adrenocorticotropic hormone (ACTH).[2] When chronically activated, this system can impair mood, immune response, and metabolic stability.[3,4] When looking at research on SKY Breath and how it interacts with these systems, it appears to restore balance by down-regulating stress hormones while enhancing those associated with recovery and emotional well-being, including prolactin and oxytocin.[5,6,7,8]
Chronic stress initiates a predictable cascade: The hypothalamus signals the pituitary to release ACTH, prompting the adrenal glands to secrete cortisol. While this response is adaptive in acute situations, persistent cortisol elevation contributes to emotional exhaustion, sleep disturbance, and systemic inflammation.[1] Emerging research shows that SKY Breath can moderate these hormones, raising what we might call “well-being” and bonding hormones (prolactin, oxytocin) and lowering the chronic stress hormones. The result: a body better equipped to rest, recover, and resist.[7,8]
What does this look like in the endocrine system? When the brain perceives threat, the hypothalamus triggers the pituitary to release ACTH (adrenocorticotropic hormone), which prompts the adrenal glands to secrete cortisol.[2,3] Cortisol is essential in the short term; it mobilizes energy stores, sharpens awareness, and suppresses non-essential functions. But when cortisol elevation persists chronically, it leads to wear and tear: mood disorders, immune suppression, metabolic dysregulation, and cardiovascular stress.[2,3]
Several studies report significant decreases in cortisol and ACTH following SKY practice. For example [6-9]: In a study of subjects with alcohol dependence, those practicing SKY showed significantly greater reductions in cortisol and ACTH over two weeks compared with controls.[8,9] Another study of undergraduate medical students found that after SKY sessions their serum cortisol levels dropped significantly before exams [10]. A broader narrative review concluded that SKY “modulates the HPA axis” and thus plays a role in reducing the fight-or-flight hormonal state.
Less commonly discussed in mainstream stress physiology, but increasingly relevant, are hormones like prolactin and oxytocin, which SKY appears to increase. One study on SKY’s neurophysiologic effects noted an increased release of prolactin and oxytocin enhancing feelings of calmness and social bonding. The research shows that SKY likely releases prolactin, vasopressin, and oxytocin through vagal afferents to the hypothalamus and anterior pituitary.
Why does this matter? Because these hormones are tied to parasympathetic activation, emotional regulation, connectivity, and resilience. The shift is not just “less stress hormones” but “more recovery / regulation hormones.” In practice, this means regularly using SKY Breath may not only reduce the negative load of cortisol/ACTH but also build the positive substrate of resilience and emotional well-being.
What does this mean for somebody interested in altering their stress hormones? That this could be a low-barrier-to-entry, non-medicated solution. Across multiple studies, Sudarshan Kriya Yoga or SKY Breath has shown measurable changes in the body’s stress chemistry. These results echo what larger reviews have found: SKY regulates the HPA axis, the body’s central stress-response system, by quieting the fight-or-flight signal and strengthening the calming influence of the vagus nerve. In turn, the body releases more “feel-good” and “bonding” hormones such as oxytocin and prolactin, creating a hormonal environment that supports trust, empathy, and recovery.[6,7,8]
This rebalancing effect has been especially notable in clinical settings. In studies of people recovering from depression, anxiety, and substance use, SKY practice not only reduced cortisol and ACTH levels but also improved mood and sleep quality—benefits that standard therapy alone did not produce. Even a single SKY session has been shown to lower stress-hormone levels and increase markers of immune strength, such as IgG antibodies, suggesting that the technique strengthens both mental and physical resilience.[6,7,8,9,10,11,12]
In everyday terms, this means that practicing SKY is more than a relaxation exercise; it’s a way to reset your body’s stress thermostat. Just a few minutes of rhythmic breathing can calm the mind in the moment, while consistent practice gradually trains the body to recover faster from pressure, regulate emotions more easily, and sustain energy throughout the day. Whether you’re a clinician helping patients manage chronic stress or someone simply looking to feel more balanced, such breathwork offers a science-backed way to harmonize your hormones and your life.
