Within the rich tradition of Iyengar Yoga, Śīrṣāsana (Headstand, a posture where the body is inverted with the head on the ground, supported by the forearms) and Sarvāṅgāsana (Shoulderstand, a posture where the body is inverted and supported by the shoulders, with the chin locked to the chest) are revered as foundational inversions, often referred to as the “King” and “Queen” of Āsanas (yoga postures). These postures are considered central to an advanced yoga practice and are believed to offer profound physiological and psychological benefits. This report aims to explore their purported impact, particularly on the intricate endocrine system, as understood through the time-honored yogic wisdom articulated by Geeta Iyengar in “Yoga: A Gem for Women” and through the lens of contemporary medical research. The objective is to provide a comprehensive and balanced analysis, bridging traditional insights with modern scientific findings to illuminate the subtle yet significant effects of these powerful inversions on women’s hormonal health.

Śīrṣāsana (Headstand): The “King of Āsanas” and its Endocrine Influence

Geeta Iyengar’s teachings present a sophisticated understanding of how Śīrṣāsana specifically affects the endocrine system through direct physical mechanisms. She posits that Śīrṣāsana directly stimulates the pituitary and pineal glands, stating that the pose “stimulates the blood supply to the brain and makes it fresh and healthy. It activates the pituitary and pineal glands which affect the health, vitality, and development of our body”. This statement underscores a belief in a direct, invigorating effect on these crucial brain-located glands. The pituitary gland, often called the “master gland,” is particularly emphasized due to its central role in controlling numerous other endocrine functions throughout the body, making its stimulation highly significant for women’s overall hormonal health and systemic regulation. This activation is also believed to contribute to a “calmer internal environment and improved emotional stability”, linking the physical practice to psychological well-being.

The Iyengar understanding suggests a specific biomechanical mechanism for this stimulation. The weight-bearing aspect of Śīrṣāsana, where practitioners are taught to “bear the weight of the body on the head and not on the hands and elbows”, is believed to create direct physical pressure that stimulates these glands. Geeta Iyengar emphasizes precise alignment, instructing practitioners to balance the body using “the crown of the head as one pole and the centre of the arches of the feet as the other pole”. This precise pressure, combined with the inverted position’s effect on circulation, is believed to increase blood supply to the brain region, stimulate the hypothalamic-pituitary axis (the primary control center for the endocrine system), activate the pineal gland’s melatonin production (a hormone crucial for sleep and circadian rhythms), and enhance overall endocrine function. If you’re curious to dive deeper into the unique qualities of Śīrṣāsana and Sarvāṅgāsana from both anatomical and symbolic perspectives, I invite you to read my post: “The Royal Inversions – Understanding the King and Queen of Āsanas”.

The designation of Śīrṣāsana as the “King of Āsanas” by Geeta Iyengar is directly related to this glandular theory and the brain’s central role. She explains, “Like the king ruling his subjects, the brain rules the numerous systems of the body. It is the controller of the intellect, the will, the memory, the imagination, and the thinking”. The brain’s overarching control extends profoundly to the endocrine system through the hypothalamic-pituitary axis, making the physical stimulation of this region through inversion particularly powerful for comprehensive systemic regulation.

The Medical Science Perspective: Exploring Physiological Pathways

While increased cerebral blood flow is often cited as a benefit of inversions, medical science notes that the brain’s autoregulation mechanisms work to maintain stable blood flow even during inverted positions. This suggests that massive, uncontrolled increases in blood flow might not be the primary mechanism for hormonal effects, but rather more subtle, regulatory influences.

Inversions trigger pressure sensors known as baroreceptors, located primarily in blood vessels in the neck and chest. This stimulation enhances autonomic nervous system responses that play a crucial role in regulating hormone secretion. The reversed blood flow towards the heart and head, coupled with baroreceptor activation, is understood to activate the “rest-and-digest” (parasympathetic) system. This activation leads to a reduction in cortisol, the primary stress hormone, and supports overall endocrine balance. Scientific studies have consistently shown that yoga interventions, which can include inverted positions, lead to decreased plasma and salivary cortisol levels in various populations. This shift towards parasympathetic dominance also lowers physiological arousal indicators like heart rate and blood pressure. The reduction in cortisol and the shift towards parasympathetic activity represents a crucial indirect pathway for hormonal balance. Geeta Iyengar’s observations about achieving a “calmer internal environment” and “improved emotional stability” through Śīrṣāsana can be substantially explained by this scientifically validated physiological shift, bridging traditional observation with a modern scientific understanding of autonomic nervous system modulation.

Regarding direct glandular effects, while the concept of direct pressure is debated, enhanced oxygen delivery to the brain region during inversions like Headstand may improve pituitary efficiency, which in turn modulates other endocrine organs. Regular yoga practice, encompassing inversions, has been associated with increased basal levels of growth hormone (GH) and dehydroepiandrosterone sulfate (DHEAS) in both men and women in one 12-week study. However, it is important to note that this study measured the effect of a comprehensive yoga regimen rather than isolated headstands, making it difficult to attribute the specific hormonal changes solely to Śīrṣāsana.

The pineal gland, primarily responsible for melatonin secretion (which regulates sleep patterns), may also be influenced by increased cerebral circulation during inversions, potentially improving sleep and mood. Scientifically, the pineal gland and its hormone, melatonin, are intricately linked to the pituitary-adrenal axis (HPA axis), influencing ACTH-cortisol levels and playing a role in mood disorders such as depression. The intricate relationship between the pineal gland, melatonin, and stress hormones provides a robust scientific basis for the significance of pineal gland function in overall health. This connection demonstrates that melatonin, influenced by the pineal, is intricately linked to stress hormones (cortisol) and mood, thereby validating Geeta Iyengar’s emphasis on the pineal’s role in “health, vitality, and development” and fostering a “calmer internal environment.” This aligns the importance of the pineal in traditional understanding with its scientifically recognized role in neuroendocrine regulation.

A critical aspect of current scientific understanding is that most available evidence regarding the hormonal effects of inversions is indirect or based on broader yoga practice, not isolated headstands in women. Claims regarding increased hormone secretion from the pituitary and pineal glands during headstand are largely based on physiological theory and anecdotal reports, rather than direct, measurable changes in hormone levels during or immediately after inversion. Specifically, no studies have conclusively demonstrated acute, measurable changes in pituitary or pineal hormone secretion due to cranial pressure or inversion in women. This consistent acknowledgment across multiple research sources that studies on yoga’s effects often involve broader, comprehensive yoga practices rather than isolated poses, highlights a common methodological limitation in holistic health research. This necessitates a nuanced interpretation of the evidence and underscores the difficulty in isolating the precise effects of individual components within a complex intervention, which is a crucial consideration for a medical researcher.

Sarvāṅgāsana (Shoulderstand): The “Queen of Āsanas” and Thyroid Regulation

Geeta Iyengar articulates a distinct focus for Sarvāṅgāsana compared to Śīrṣāsana. While Headstand targets the upper endocrine glands, Shoulderstand is understood to primarily work on the thyroid system. She explains the specific mechanism: “Due to the firm chinlock the thyroid and the parathyroid glands get ample supply of blood, thereby increasing their efficiency in maintaining the body and the brain in good balance”. This highlights the importance of the chinlock in creating a targeted effect on these glands.

The Medical Science Perspective: Evidence for Thyroid Hormone Modulation

Medical understanding supports that Sarvāṅgāsana, particularly when combined with Jālandhara Bandha, can influence the thyroid gland. This influence is believed to occur through increased blood circulation to the neck region and gentle mechanical pressure exerted on the thyroid gland, which may stimulate its function and hormone secretion. The chin lock (Jālandhara Bandha) is specifically noted in research for its potential positive impact on thyroid activity, suggesting an influence on the complex hypothalamic-pituitary-thyroid axis. If this connection between yoga, hormonal rhythms, and menstrual health resonates with you, you may enjoy my article “Reflecting on Ayurveda and Iyengar Yoga“, where I offer more insights on how ancient practices support women’s well-being.

Current research and clinical observations indicate that Sarvāṅgāsana with Jālandhara Bandha can indeed influence thyroid hormone levels—specifically TSH (Thyroid-Stimulating Hormone), T3 (Triiodothyronine), and T4 (Thyroxine). A controlled study on women with hyperthyroidism demonstrated that a 90-day yoga program (which included asanas, pranayama, mudra, and bandha, thus a comprehensive approach) led to a statistically significant decrease in T4 levels in the yoga group compared to controls. This indicates that yoga, as part of a broader regimen, can help normalize elevated thyroid hormone levels in hyperthyroid patients. Additional studies cited in reviews found that yoga practices can significantly increase T3 levels in hypothyroid patients and also affect TSH levels, helping to bring thyroid function closer to normal ranges. General reviews and expert consensus highlight Sarvāṅgāsana as a beneficial posture for regulating thyroid hormone production, particularly for hypothyroidism, by improving blood flow and stimulating the gland. The consistent finding that yoga helps normalize thyroid hormone levels (decreasing high T4 in hyperthyroidism and increasing low T3 in hypothyroidism) rather than simply increasing or decreasing them, strongly suggests a homeostatic or balancing effect. This aligns precisely with the holistic aim of yoga to bring the body into equilibrium and directly supports Geeta Iyengar’s claim of “maintaining the body and the brain in good balance.”

It is important to acknowledge that most studies assess the effect of a comprehensive yoga regimen, not just Sarvāṅgāsana with Jālandhara Bandha in isolation. This consistent caveat in the research is a critical methodological limitation. While there is strong evidence for the overall yoga intervention’s positive impact on thyroid health, definitively attributing the observed effects solely to Sarvāṅgāsana is scientifically challenging. Furthermore, sample sizes in many studies are often small, and long-term effects are less well-documented. The precise, isolated impact of this specific posture and bandha on TSH, T3, and T4 levels in healthy individuals versus those with pre-existing thyroid disorders may also differ and requires further targeted research.

Broader Hormonal and Systemic Benefits of Yoga Inversions for Women’s Health

The pituitary gland, as the “master gland,” controls FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) production, which are direct regulators of menstrual cycles. Geeta Iyengar notes that specific inversion variations can “help regulate the menstrual flow and check leucorrhoea (vaginal discharge)”. Furthermore, she emphasizes that “a healthy menstruation depends upon the proper functioning of the ovary and this, in turn, upon a healthy pituitary gland” , underscoring the pituitary’s foundational role.

Scientific evidence suggests that regular yoga practice has positive effects on the menstrual cycle and overall psychological well-being, likely by balancing the neuro-endocrinal axis. Specifically, Yoga Nidra (a yogic relaxation technique) has demonstrated significant improvements in anxiety, depression, positive well-being, and hormonal levels in women experiencing menstrual irregularities. Research also indicates that yoga therapy can improve hormonal and biochemical changes related to both the hypothalamo-pituitary-adrenal (HPA) axis and the hypothalamo-pituitary-ovarian (HPO) axis in conditions such as Polycystic Ovary Syndrome (PCOS). Stress is identified as a significant factor influencing the menstrual cycle through these neurohormonal connections. However, it is important to note a nuance: some studies on dysfunctional uterine bleeding (DUB) showed no significant changes in direct physiological markers like blood loss (PBAC) or endometrial thickness (ET), despite effectively reducing stress and anxiety. This suggests that while yoga clearly influences the regulatory systems (neuro-endocrine axes) and psychological state that underpin menstrual health, its direct impact on all physical manifestations of menstrual disorders (e.g., volume of blood loss) might be limited or condition-specific. This refines the understanding of “menstrual regulation” and emphasizes the profound mind-body connection in reproductive health.

Geeta Iyengar acknowledges the complex endocrine changes involved in hormonal transitions during menopause. She specifically recommends certain poses for “unsteady mental condition in menopause”, implying that the hormonal balancing effects of glandular stimulation contribute to mental and emotional stability during this phase.

Randomized controlled trials provide strong evidence for yoga’s benefits during menopause. Hatha Yoga practice has been shown to significantly decrease menopausal symptoms, stress levels, and depression symptoms, while markedly improving quality of life in post-menopausal women. Critically, one study found that yoga practitioners exhibited decreased levels of FSH and LH (hormones typically elevated in menopause) compared to control groups. Additionally, while the control group showed a significant increase in cortisol, yoga and exercise groups did not, indicating a buffering effect against stress. Overall, yoga has been shown to reduce psychological, somatic, and urogenital symptoms commonly experienced in menopause. The observed decrease in FSH and LH levels in post-menopausal women practicing yoga is particularly significant. I spoke about the impact of yoga on menopause in my talk “Aligning with Change” — a recorded lecture exploring how Iyengar yoga addresses the transitions of midlife.

In menopause, these hormones are typically high due to the ovaries’ reduced estrogen production and the pituitary’s attempt to stimulate them. A decrease suggests that yoga might be influencing the pituitary’s feedback loop, potentially helping to modulate the intensity of hormonal fluctuations and associated symptoms during this transition, rather than just alleviating symptoms. This provides a more specific hormonal mechanism beyond general stress reduction.

The pituitary-ovarian axis is central to controlling fertility and reproductive function. In the Iyengar tradition, inversions are specifically recommended for conditions such as “uterine displacement, and menstrual disorders”, highlighting a belief in their direct therapeutic impact on reproductive organs.

While much of the recent research on yoga and reproductive health has focused on male infertility, broader systematic reviews indicate yoga’s positive impact on “hormonal balance, ovarian function, menstrual irregularities, and stress reduction” for overall fertility. Yoga contributes to maintaining sperm telomere length and genomic integrity, and helps reduce oxidative stress, all of which are crucial for optimal reproductive health. Notably, one review explicitly mentions specific asanas, including Sarvāṅgāsana (Shoulderstand), as being able to “stimulate reproductive organs, enhance blood circulation and regulate hormone production”. Yoga also plays a role in modulating the hypothalamic-pituitary-adrenal (HPA) axis, a key factor in fertility due to stress’s impact on reproductive hormones. The scientific literature, even when primarily focused on male infertility, provides general support for yoga’s role in overall reproductive health by influencing hormonal balance, reducing oxidative stress, and modulating the HPA axis. The explicit mention of Sarvāṅgāsana stimulating reproductive organs and regulating hormone production provides a rare direct scientific corroboration for a specific Iyengar claim regarding this pose’s effect on reproductive health, bridging traditional wisdom with modern findings.

Supporting Mechanisms: Beyond Direct Glandular Pressure

The inverted position of Śīrṣāsana and Sarvāṅgāsana is believed to reverse gravity’s pull, aiding lymphatic drainage and toxin removal, thereby reducing inflammatory burdens on endocrine organs. Regular yoga practice generally helps bolster the immune response, which is important given the shifts in hormone levels throughout the menstrual cycle and other life stages. Inversions can also relieve pressure on spinal nerves, which in turn may improve neural signaling to various glands, optimizing their function.

A consistent and robust theme across numerous scientific studies is yoga’s profound ability to reduce psychological stress and anxiety. This stress reduction profoundly impacts the HPA axis and, consequently, numerous hormonal systems throughout the body. This is a primary, scientifically robust mechanism for many of yoga’s observed benefits, providing a strong evidence base for its holistic impact on hormonal balance. This pervasive evidence suggests that stress reduction is a foundational and pervasive mechanism through which yoga, including inversions, influences hormonal balance. This offers a robust scientific explanation that complements, and in some cases, provides an alternative to, the traditional focus on direct glandular stimulation, highlighting the systemic and holistic nature of yoga’s benefits. The body is understood as a “myriad of interconnecting systems,” including the endocrine, lymphatic, and nervous systems, all of which are relevant to the menstrual cycle and overall health. This holistic view, deeply embedded in yogic philosophy, aligns well with modern scientific understanding of psychoneuroimmunology, which explores the complex interactions between psychological processes, the nervous system, and the immune system.

Important Considerations and Contraindications for Inversions

Geeta Iyengar, with her nuanced understanding of the body, provides specific modifications for individuals with certain conditions that might be adversely affected by the intense glandular stimulation of inversions. For those “suffering from heaviness or irritation in the uterus, discharge or other menstrual disorders,” she recommends keeping “the heels apart and the toes touching each other in Śīrṣāsana; this will ease the pressure on the uterus and the groins”. This demonstrates an acute awareness that the hormonal effects of the pose can be too intense or counterproductive for certain conditions and thus require careful modulation.

Both traditional wisdom and modern medical advice largely align on key contraindications for inversions, emphasizing safety:

• High blood pressure: Inversions can significantly increase pressure in the head and heart, potentially worsening symptoms of dizziness or breathlessness for individuals with hypertension.
• Glaucoma or other eye problems: The increased pressure in the head during inversions is believed to weaken blood vessels in the eyes, which could potentially exacerbate conditions like high myopia or glaucoma.
• Neck injury or pain: Inversions, particularly Headstand, place considerable strain and weight on the cervical spine, making them contraindicated for individuals with pre-existing neck injuries or chronic pain.
• Heart disease or stroke: The inverted position can put significant pressure on the heart due to the altered blood flow and the weight of abdominal organs, posing risks for those with heart conditions or a history of stroke.
• Pregnancy: While some experienced practitioners might continue inversions with modifications, beginners should strictly avoid learning or practicing these poses for the first time during pregnancy. Any inversion practice during pregnancy should always be undertaken under the direct guidance and support of a highly experienced and qualified yoga teacher.
• Menstruation: This is a particularly strong and consistent contraindication across both traditional Iyengar teachings and modern advice. Geeta Iyengar provides specific modifications, implying a need to modulate the pose’s effects during this time. Modern sources explain that inverted actions are “counter to the body’s need to dispense bodily matter” and that directing “prana” (life force) upwards can disrupt the natural downward flow of menstruation, potentially leading to menstrual problems such as irregular periods or complete stoppage of flow. The strong consensus on contraindications for menstruation across both traditional and modern sources highlights a shared, empirically derived understanding of the specific physiological impact of inversions on the female reproductive system during this phase. This convergence, despite differing explanatory frameworks (e.g., “prana” versus physiological flow dynamics), suggests a robust observation of the body’s response and underscores the paramount importance of respecting natural physiological rhythms in yoga practice.
• Other conditions: Individuals with ear infections, sinusitis, hernia, or acid reflux should also avoid inversions.

The Iyengar method places significant emphasis on precise alignment and sustained duration in Śīrṣāsana—often building up to 5-10 minutes of practice. This suggests a belief that sustained glandular stimulation is necessary for therapeutic benefit, supporting the theory that these effects are cumulative and depend on consistent practice over time. It is crucial to understand that excessive effort or improper technique in inversions can increase blood pressure and lead to strain, potentially counteracting the intended benefits. Given the complexity and potential risks, it is always recommended to practice inversions under the direct guidance and supervision of an experienced and qualified yoga teacher.

Conclusion: Harmonizing Tradition and Science for Holistic Well-being

The exploration of Śīrṣāsana and Sarvāṅgāsana reveals a fascinating intersection between ancient yogic wisdom and contemporary medical science regarding their hormonal effects. While direct, acute hormonal changes from isolated inversions are not always robustly documented by current scientific methods, the broader physiological mechanisms—such as profound stress reduction, modulation of the autonomic nervous system towards parasympathetic dominance, and improved circulation—provide strong scientific support for many of the holistic benefits observed and taught in the Iyengar tradition. Geeta Iyengar’s detailed observations, nuanced instructions, and specific modifications suggest a profound empirical understanding of the body’s responses to these powerful poses, an understanding that modern science is gradually beginning to elucidate and validate through different explanatory frameworks.

The potential benefits of inversions for hormonal balance and overall health are significant, including their influence on the pituitary, pineal, and thyroid glands, and their broader positive impacts on women’s health across menstrual regulation, menopausal support, and reproductive well-being. However, it is paramount to respect established contraindications and practice these poses under qualified guidance to ensure safety and maximize therapeutic effectiveness. The current limitations of scientific research, particularly the challenge of isolating the effects of individual poses within comprehensive yoga interventions, highlight a clear need for continued, more targeted, and rigorous studies. Such research would further unravel the precise mechanisms and acute hormonal impacts of Śīrṣāsana and Sarvāṅgāsana, thereby deepening our scientific understanding of these ancient practices.

If this article inspired questions or reflections about your own practice, you’re warmly invited to schedule a one-on-one session through “Talk Yoga with Agi“, where we explore how yoga philosophy and practice can meet your individual path with clarity and care.

Reflective Questions for Your Practice and Understanding

• How does understanding both the traditional yogic perspective and the contemporary scientific findings deepen the appreciation for yoga’s intricate effects on the human body and its hormonal systems?
• In one’s own yoga practice, or in observing others, have any of the subtle or profound hormonal shifts or systemic benefits described in this elaborate article been personally noticed?
• Considering the scientific limitations regarding direct, acute hormonal measurements from isolated inversions, how might this knowledge inform the approach to teaching or practicing these poses, particularly when addressing specific health conditions or making therapeutic claims?
• Given the consistent emphasis on stress reduction as a primary and scientifically robust mechanism for yoga’s hormonal benefits, how can this understanding be integrated into a more holistic approach to hormonal health, both on and off the yoga mat?
• What role does sustained, consistent practice—as emphasized in the Iyengar tradition—play in realizing the long-term hormonal and systemic benefits of inversions, beyond any immediate acute effects?

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Further Reading and Resources:

1. Rocha, K., et al. (2012). Plasma serum cortisol was decreased after a yoga intervention in healthy controls. (Cited in: “Yoga practices traditionally involve multiple components including physical postures with stretching, breathing exercises and deep relaxation.” PMC4174464)
2. Bratborska, A. W., & Piotrowski, I. (2024). The impact of yoga practice on cortisol levels in breast cancer patients—a comprehensive review. Oncology in Clinical Practice, 20(6), 420-427.
3. Banasik, Jacquelyn, et al. “Effect of Iyengar yoga practice on fatigue and diurnal salivary cortisol concentration in breast cancer survivors.” Journal of the American Association of Nurse Practitioners 23.3 (2011): 135-142.
4. Corey, Sarah M., et al. “Effect of restorative yoga vs. stretching on diurnal cortisol dynamics and psychosocial outcomes in individuals with the metabolic syndrome: The PRYSMS randomized controlled trial.” Psychoneuroendocrinology 49 (2014): 260-271.
5. Yadav, Anjali, Prabhakar Tiwari, and Rima Dada. “Yoga: As a Transformative Approach to Addressing Male Infertility and Enhancing Reproductive Health in Men: A Narrative Review.” Journal of Human Reproductive Sciences 17.4 (2024): 224-231.
6. Yadav, Anjali, Prabhakar Tiwari, and Rima Dada. “Yoga and lifestyle changes: A path to improved fertility–A narrative review.” International journal of yoga 17.1 (2024): 10-19.
7. Abiç, Arzu, and Duygu Yilmaz Vefikuluçay. “The Effect of Yoga on Menopause Symptoms: A Randomized Controlled Trial.” Holistic nursing practice 38.3 (2024): 138-147.
8. Jorge, Márcia P., et al. “Hatha Yoga practice decreases menopause symptoms and improves quality of life: A randomized controlled trial.” Complementary therapies in medicine 26 (2016): 128-135.
9. Bhanderi, Priti, et al. “Effect of Yoga on Mental Stress, Lipid Profile, and BMI in Wives of BSF Personnel.” Journal of Pharmacy and Bioallied Sciences 17.Suppl 1 (2025): S290-S292.
10. Wetterberg, Lennart. “The relationship between the pineal gland and the pituitary-adrenal axis in health, endocrine and psychiatric conditions.” Psychoneuroendocrinology 8.1 (1983): 75-80.