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Is it dangerous to practise yoga on the full moon?

05 May 2017

"The moone is founde, by plaine experience, to beare her greatest stroke uppon the seas, likewise in all things that are moiste, and by consequence in the braines of man.”
(C.16, Moon Lore)

A yoga class this month happened to fall on the eve of the full moon. At the beginning of class, a student informed the group that it was a full moon and asked if I thought it was ok for us to practice āsana - postures. He was concerned that perhaps we were more likely to injure ourselves at this time in the lunar cycle.

I explained that in the yoga style known as Ashtanga Vinyasa, there is a convention of not practising on days upon which the moon is either full or new, but that this is not a part of the teachings I’ve received or share. A lively group discussion ensued about the possible effects of the waxing and waning moon and its relationship with our lives and yoga practice. Although I could offer no rational motive for abstaining from āsana, I nonetheless found myself wondering if perhaps tonight we should practise more gently.

“It has always been the tradition in Ashtanga Yoga to rest from asana practice on new and full moon days.” - Jois Yoga

The most popular and also puzzling explanation for the observance of so-called ‘moon days’ is that it is due to an excess of prāṇa - energy, resulting from the supposed relationship between the gravitational pull of the moon and the cycle of respiration:

“Like all things of a watery nature (human beings are about 70% water), we are affected by the phases of the moon. …Both sun and moon exert a gravitational pull on the earth. Their relative positions create different energetic experiences that can be compared to the breath cycle. The full moon energy corresponds to the end of inhalation when the force of prana is greatest. This is an expansive, upward-moving force that makes us feel energetic and emotional, but not well grounded. The Upanishads state that the main prana lives in the head. During the full moon, we tend to be more headstrong.”
- Ashtanga Yoga Center

Although this explanation has an air of credibility, it is based upon flawed science and popular mythology. Whilst it is true that watery bodies such as the ocean are influenced by the gravitational force of the moon, this in no way corresponds to the phases of the moon. The degree of gravitational force is dependent upon the mass of the moon and its distance from the earth. The mass remains constant and the distance can fluctuate each month between perigee (its smallest distance to the earth) and apogee (its greatest distance.)

Perigee and apogee can occur at any phase during the lunar cycle.

There is no explanation in the myth as to how the “full moon energy” corresponds to the end of inhalation or why the force of prāṇa (another problematic concept for the material scientist) is greatest at this time in the breath cycle. Even if one accepts through the study of haṭha yoga the popular assertion that prāṇa (vāyu) is an ascending subtle energy force, there is no demonstrable correlation between this kind of energy and the gravitational pull of the moon.

The logical fallacy here is that at these times of the month an excess of prāṇa will render the practitioner “more headstrong” and thus more likely to suffer injury:

“Traditionally Astanga yoga is not taught on moon days (days when there is a full or a new moon), as the potential for injury is greater.” - Ashtanga Yoga London

Such a theory raises more questions than it answers and there is no evidence to show a relationship between injury and lunar phases.

Moon days and astrology

The concept of a moon day originates in Indian astrology: Jyotisha (meaning ‘light,’ or heavenly body.) Within Jyotisha, a tithi is the name for a lunar day or the time it takes for the longitudinal angle between the moon and the sun to increase by 12 degrees; this can take between 19 and 26 hours. A more accurate translation would be ‘lunar phase.’

“What loosely gets termed the full and new ‘moon days’ – from our teacher’s (Sharath Jois) perspective – are actually the 15th and the 30th tithis of this Indian Astrology (Jyotish) system.” - Jois Yoga

Within this system, there are approximately 30 tithis in each month with each phase presided over by a specific Deity and a variety of recommended auspicious activities. The new moon tithi is called Amavasya and the full moon, Purnima. On the new moon, the performance of austerities is recommended, and on a full moon, fire ceremonies & merry-making are endorsed.

In Jyotisha, the moon is associated with the mind. Similarly, in western astrology, the moon corresponds with emotion, memory and the unconscious mind. The first-century poet Mallinus described the moon as ‘melancholic’ and the moon is often associated with insanity and intoxication. Fear of the moon is like some dark spectre lurking in the depths of our collective psyche and throughout history, a host of unspeakable evils and madness have been attributed to the influence of the moon. The word ‘lunatic’ originates in the French for the moon ‘la lune.’

Like its western counterpart, Indian Astrology has been universally rejected by the scientific community, who have been unable to find a substantive basis for many of its claims.

Moon days in the yoga tradition

In the tradition of haṭha yoga, from which a number of ashtanga vinyasa practices originate, it is commonplace for texts to begin with strict warnings, and injunctions for practice, many of which seem archaic or misogynistic. For example, the 15th-century Haṭha Pradīpikā states that: “one should avoid the association of wicked people, fire, women, long walks, morning baths, skipping food and excessive physical strain.” (HP 1.49)

Additional instructions are typically given for suitable accommodation, season, climate and diet with some texts issuing dire warnings to those students who fail to observe said customs.

Although I am yet to find a text that specifically warns against practice at times of a full or new moon, ‘candra - the moon, is certainly a recurrent image in the symbolism of haṭha Yoga. Candra is often associated with the subtle energetic pathway known as ‘Iḍā nāḍī’ and also denoted as a source of ‘bindu’ or ‘amṛta’ residing in the crown of the head. A comparatively late, creative interpretation of the word ‘haṭha' is found in the Yoga-Bija which equates ‘Ha’ with the sun and ‘Ṭha’ with the moon.

Candra is typically cast in the role of passive, inert and cool. In the Yoga Yajnavalkya, the yogin is advised to assume a steady, comfy posture “steadying his gaze well on the tip of the nose, always focusing on the moon with its cool rays, with the flow of nectar from the tip of the head.” (YY 5.15)

The observance of moon days does not appear to be a feature of either traditional haṭha yoga, or of Patañjali’s Aṣṭâñga-yoga from which modern ashtanga vinyasa detrains its philosophical and metaphysical authority. The only explicit reference to the moon in Patañjali’s Yogasūtra is found in book three which states that through meditation upon the moon, “comes knowledge of the starsarrangement.” (YS 3.28) In Vacaspati Misra’s tenth-century commentary on the Yogasūtra, we find the enduring metaphor of Puruśa compared to the moon reflecting on a body of water.

A tradition of ashtanga yoga?

It is likely that within the lineage of ashtanga vinyasa, “the tradition of resting on moon days” began with Sri K. Pattabhi Jois. His teacher, T. Krishnamacharya, did not observe moon days or mention them in his magnum opus Yoga Makaranda (1934). A few years ago, I attended a course with Srivatsa Ramaswami who was a student of Krishnamacharya. When questioned about moon days, Ramaswami said that during 30 years of study with Krishnamacharya, they continued with classes and practice regardless of the phases of the moon and that this did not form any part of Krishnamacharya’s teaching. When pressed further he said that he believes the convention came about from a time in India when most teachers (like Jois) were Brāmaṇas - priestly caste. On full moons and new moons, the Brāmaṇas have many temple duties and rites to attend to so that it meant that they didn’t have time to teach on those days. Although there were no taught classes, students were still expected to continue with their studies.

This fits with what Eddie Stern said in a letter to Barry Silver about moon days, published in 2014:

“…the reason for Pattabhi Jois's observance of these days is quite simple. As you know, the Maharaja's Pathashala (Sankrit College) was closed each month for classes on the moon days, and the day before and after. Studies were continued by the students, but no new lessons taught. One reason for this was that on amavasya and purnima, certain rituals had to be performed by the teachers and students alike, who are all brahmins - for example, the pitr tarpana which needs to be performed on amavasya, and the ritual bathing the day after the moons – all these things take time to be performed…Since Pattabhi Jois was a student at the Maharaja's Pathashala, and was the Professor of Yoga at the college from 1937 to 1973, taking those days off from teaching became a habit and observance for him.”

The name ‘Jois’ is a south Indian interpretation of the word Jyotish and astrology was a family tradition. Moon days would have certainly been a significant time within the Jois household. In Jois’ book Yoga Mala (1962) the only reference to moon days is within the context of (patriarchal) guidelines for Brahmacayra - sexual conduct. Jois recommends that should these times of the month coincide with the optimum phase of the female reproductive cycle then: “union with one’s lawful wife should be undertaken for the sake of begetting good progeny.” Jois makes no mention of observing moon days with regard to āsana practice.


My theory is that Pattabhi Jois didn’t teach on moon days because he was either otherwise engaged in temple (and/or marital) duties, or that he had become accustomed to resting at this time of the month. Over time, this became a convention of the practice and a rule that some of his students felt necessary to preserve. This makes more sense than it being to do with the rising flow of prāṇa or the gravitational field of the moon. Perhaps ashtanga practitioners developed their own theories about the rule and its mythology took on a life of its own.

The appropriation of astrology imbues ashtanga with mystique and infuses the 6 days a week, 52 weeks a year, practice treadmill with an added dimension of cosmic significance. However, to state that “it has always been a tradition of ashtanga yoga to rest on moon days” depends upon a somewhat liberal interpretation of the word ‘traditional’ and a conflation with the earlier tradition of Patañjali’s aṣṭâñga yoga, in which moon days are not a feature. The ashtanga vinyasa brand often relies on tradition appeal to posit an image of authority and authenticity, yet many of its protocols fail to stand up to the scrutiny of textual & historical analysis.

The observance of moon days has more to do with fallacy, astrology, and the practicalities of Brahmanical duties than it does with yoga. There is no evidence to support any of the popular myths surrounding this custom. There are plenty of legitimate causes of injury during yoga āsana practice but I do not believe that the moon is one of them. To attribute culpability to the moon diminishes human agency and responsibility. Whilst there may be some merit in adhering to the dictates of paramparā - lineage, it is also important to engage critically with dogma and superstition. I have personally practised on moon days for many years, both dynamic (including ashtanga) and soft forms of āsana-based yoga and haven’t experienced any adverse effects that I’m aware of. I suspect that confirmation bias plays a large part: i.e. if you think that your practice is going to be adversely affected by the moon then you will find a set of reference points to affirm this belief; conversely, if you don’t believe it will make a difference then it probably will not.

My advice is to enjoy your practice without worrying about the moon!



• Birch, Jason. (2011) The meaning of haṭha in Early Hathayoga. Journal of the American Oriental Society 131(4): 527-554
• Bernard, Theos. (2007) Hatha Yoga, The Report of a Personal Experience, Harmony Publishing, Edinburgh
• Burley, Mikel. (2000) Haṭha Yoga: its Context, Theory and Practice Motilal Banarsidass,Delhi
• Feürstein, Georg. (2008) The Yoga Tradition Hohm Press, Arizona
• Gharote, Dr. M.L. (2006) Hathapradīpikā of Svātmārāma (10 chapters) The Lonavla Institute, India
• Gharote, Dr. M.L. (2009) Haṭharatnāvalī of Śrīnivāsa Yogi The Lonavla Institute, India
• Jois, K. Pattabhi (2010) (1962) Yoga Mala North Point Press, New York
• Krishnamacharya, T. 2011(1934) Yoga Makaranda, The Nectar of Yoga English Translation by TKV Desikachar, Media Garuda, Chennai
• Mallinson, James (2004) The Gheranda Samhita, Woodstock, NY
• Mallinson, James (2007) The Shiva Samhita, Woodstock, NY
• Mallinson & Singleton (2017) Roots of Yoga Penguin Classics, Penguin Books
• Mohan, A.G. (2013) Yoga Yajnavalkya, Svastha Yoga Pte Ltd, India
• Muktibodhananda, Swami (1998) Hatha Yoga Pradipika Yoga Publications Trust, Bihar
• Niranjanananda, Swami (2012) Gheranda Samhita Yoga Publications Trust, Bihar
• Satchidananda, Swami (2005) (1978) The Yoga Sutra of Patanjali Integral Yoga Publications, Virginia
• Singleton, Mark. 2010 Yoga Body, The Origins of Modern Posture Practice Oxford University Press, New York
• Sjorman, N.E. (1999) The Yoga Tradition of the Mysore Palace Shakti Malik Abhinav Publications, Delhi
• White, David. (2014) The Yoga Sutra of Patanjali, A Biography Princetown University Press, New Jersey

Web resources

• Freer Sackler - Yogic Identities: Tradition and Transformation (By James Mallinson)
• Academia.Eu - Brill Encyclopedia - Hatha Yoga (By James Mallinson)
Vedic” Astrology: A Strange and Lovely Art from Time Gone By, Rife with Tender Bullshit Today - Matthew Remski
• Eddie Stern on Moon days in Ashtanga yoga - Yoga Mama -
Jyotisha Vidya -
Moon Lore, by Timothy Harley -
• Jois Yoga -
• Ashtanga Yoga London -
• Ashtanga Yoga Centre -

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About James

James is a yoga teacher and researcher who's practised yoga for over 23 years. He holds an MA in Traditions of Yoga & Meditation from SOAS, University of London, where he continues to study postgraduate Sanskrit.

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