BOOK REVIEW: Yoga Anatomy, 3rd Ed. by Leslie Kaminoff and Amy Matthews

Yoga AnatomyYoga Anatomy by Leslie Kaminoff
My rating: 5 of 5 stars Page

This book has several competitors, and so this review will focus on a few of the features that I believe make it one of the best books on yoga anatomy, and the most appropriate for many users. To clarify, H. David Coulter’s “Anatomy of Hatha Yoga” has some advantages over this book, but Coulter’s book is also denser and will send neophyte readers to the glossary / internet / library much more often. On the other hand, some of the other yoga anatomy books fixate entirely on postural yoga and treat it entirely as a matter of skeletal alignment and muscular engagement. While a lot of this book (and any such book, really) focuses on skeletal alignment and muscular engagement, I appreciated the books exploration of breath and the nervous system – topics that are often neglected. In short, this book offers a mix of reader-friendliness and detail that makes it at once approachable and tremendously informative.

One important feature of this book is that it avoids the dogmatism of some yoga texts, encouraging experimentation and recognizing that a one-size-fits-all approach to bodies is bound to fail. This can best be seen in the “Cueing Callout” boxes that explore the pithy adjustment directives for which yoga teachers are famous (and often satirized,) advice that is often misunderstood in ways detrimental to a student’s progress.

A second key feature involves keeping anatomy and physiology distinct from the folk science of yoga / ayurveda. While Kaminoff and Matthews do refer to ideas like prana and apana, they do so in a broad, conceptual way that doesn’t conflate said ideas with science. A common problem in yoga texts is conflation of science with folk science such that confused readers are left with a muddle of puzzle pieces that don’t belong to the same puzzle.

Finally, as one who’s found pranayama (breathwork) to be one of the most profoundly transformative elements of a yoga practice, I appreciated that the book not only had a chapter on breath dynamics, but that all the posture discussions included a “breath inquiry” section that encouraged readers to reflect upon the effect of the posture on breathing, as well as suggesting ways in which a practitioner might experiment to improve one’s breathing.

The only criticism I have is that many of the text-boxes in the early chapters seemed to contain random information that could have been incorporated into the text, into footnotes, or edited out altogether. [In contrast to the aforementioned “Cueing Callout” boxes that had a clear and distinct purpose.] If you’re a yoga teacher or dedicated practitioner without a deep scientific background, you’d be hard-pressed to do better than this book for learning about the anatomy of yoga.

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BOOK REVIEW: Immunity by Jenna Macciochi

Immunity: The Science of Staying Well—The Definitive Guide to Caring for Your Immune SystemImmunity: The Science of Staying Well—The Definitive Guide to Caring for Your Immune System by Jenna Macciochi
My rating: 5 of 5 stars Page

This is a book about how to keep one’s immune system firing on all cylinders, and it reports on the scientific findings about how a range of lifestyle activities (e.g. exercise, sleep, and nutrition) impact upon the robustness of one’s immune response. The book was exceedingly timely, having been put out last spring in the early days of the pandemic [though I was delinquent in getting to my review until now.]

The book consists of just seven chapters, though they are substantial in length and extent of discussion of the respective topics. The first chapter offers a primer on the immune system, its components, and how it does its crucial job. This chapter also explains how vaccinations work, what autoimmune diseases and allergies are, and what role genetics (nature) and lifestyle / environment (nurture) play in immunity.

Chapter two investigates a range of topics at the nexus of lifecycle and immunity, including: differences between male and female immune responses, pregnancy and immunity, and the effects of aging and menopause on immune system activity.

Chapter three is about our intestinal microbiomes and immunity. If this seems like a strange topic to devote an entire chapter to, you probably haven’t been following the voluminous outpouring of research findings about how our helpful microbiological lifeforms are being shown to have a profound impact on all aspects of human health and well-being from mental health to, well, immune system robustness.

Chapter four explores how immune system activity is compromised by lack of sleep or poor-quality sleep. However, it also looks more broadly at how our immune system responds to the various cycles in which it finds itself — from the daily cycle of days and nights to the yearly seasonal cycle.

Chapter five considers the nexus of mental health and immune response. As was mentioned with respect to the gut, the connections between physiological activity and mental health are becoming ever more apparent – though there remains much to be understood.

The penultimate chapter is about fitness and physical activity and what is know about why exercise is so good for one’s immune response. Of course, there seem to be diminishing marginal returns (less benefit for a given additional workout) and even diminishing returns (negative outcomes) if one goes too crazy with one’s exercise regiment and doesn’t give one’s body adequate amounts of rest.

The final chapter is about the role of nutrition in immune system activity. The approach is very much accord with my own beliefs which are that if one eats right, there is little need for supplements, and no volume of supplements will save you from a poor diet. The emphasis is upon a high-fiber diet rich in plant nutrients and balanced to provide all necessary macro- and micronutrients, while debunking fads and dietary myths. There is discussion of many of the foods that are traditionally associated with immunity (echinacea, elderberry, turmeric, etc.,) and what claims seem to hold and which are unproven.

If you don’t know a lot about the science of healthy lifestyles, this book offers an additional benefit in that it approaches the topic from a quite basic level. That is, it provides a lot of background information that would be useful for a complete neophyte to understand the points about immune activity. So, for example, the author lays out rudimentary explanations of micronutrients or sleep cycles before getting into the relevant information about how these impact on immunity. Of course, the flip side is that for those who have studied this science, it may take some skimming because there is a lot of material that will probably be elementary to those who practice healthy living.

I found this to be an extremely beneficial book. Its focus upon what one can do to improve immune robustness makes it tremendously useful for the average reader. It presents the science without getting too deep in the weeds of detailed physiological activity. I felt the author did an excellent job of walking the line to produce a book that is useful, readable, and digestible.

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BOOK REVIEW: The Immune System: A Very Short Introduction by Paul Klenerman

The Immune System: A Very Short IntroductionThe Immune System: A Very Short Introduction by Paul Klenerman
My rating: 5 of 5 stars

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This is a volume in the “A Very Short Introduction” [AVSI] series put out by Oxford University Press on a wide variety of scholarly subjects. As the series title suggests, the central objective of AVSI books is to pack as much of the fundamentals of a topic into as slim a package as possible. I read quite a few of these to get the gist of a subject without a lot of extraneous information. In short, they are brief and provide a high caliber understanding of the topic, but they aren’t written to be entertaining and they assume a basic scientific literacy. They usually weigh in at between 100 and 200 pages. (In this case, 144 pp.)

I found the seven chapters were optimally arranged. Chapter 1 describes and delineates the immune system, which isn’t as easy as it might seem. Putting the immune system inside neat borders is hard. If you simply describe it as the body’s defensive system, you quickly run into problems at the edges of competing classification. Sure, B cells and T cells are clearly part of the immune system, but what about skin and mucus membranes? Where does the lymphatic system end and the immune system (which uses it extensively) begin?

Chapters two and three explore the two major divisions of the immune system: the innate and the adaptive. These days, with COVID-19 at the center of global attention, the distinction is probably clear to most. The innate system isn’t geared to take on specific invaders. It has the advantage of being able to fight almost any invader, but the disadvantage of not being able to keep up with invaders that grow rapidly, are good at disguise, or both. An adaptive system response is what we all lack for COVID-19 because it only recently jumped to our species (well not “all of us,” those who had it and are recovered have adaptive immunity and that’s why they don’t have to worry about getting it again [those who have properly working immune system, at least.]) The adaptive response recognizes specific invaders and can raise an army against them tremendously quickly. Vaccines train the adaptive system to build such a response (typically by injecting a weakened strain into the body, but more detail is provided in the final chapter.)

Chapter four is entitled “making memories,” and it is an extension of chapter three. It further investigates adaptive immunity by focusing on the question of how the body develops a memory of those invaders it’s crushed in the past (or that it learned to crush by way of vaccination.)

The next two chapters delve into the two opposing ways the immune system can fail. Chapter five is about immunological failure, or how and why the body sometimes isn’t up to defeating invading adversaries. Most famously this is seen in HIV / AIDS patients, but there are other ways that the system fails in its job as the body’s bouncer. Chapter six looks at what happens when the immune system is too aggressive. [It’s important to realize that not only does the immune system check out foreign bodies, it also checks the tags on the body’s own cells, killing those that don’t display a proper “tag.”] The two major categories of over-performance are: autoimmune disorders (when the body wrongly attacks its own cells) and allergies (when the body goes all “This is Sparta!” on relatively benign foreign objects.)

The last chapter looks briefly at what work is being done in medicine these days involving the immune system, including approaches to vaccines, immunotherapy, biological therapies, and work on inflammation and the how the immune system is linked to aging.

If there was one topic I wish was better (more extensively) handled it would be discussion of what is known about how and why lifestyle choices influence immune system operation. There was a mention of how smoking has been linked to a specific immune system deficiency, and a general comment on how diet and exercise appear to be linked to increased effectiveness of autophagy (the body’s process of self-consumption and recycling of cells,) but that’s pretty much it. As there is a lot to cover in a small space, it’s hard to be too critical about this, but it seems like a crucial topic (if not as scientifically sexy as vaccine research, which is discussed relatively extensively.)

I found this book did as advertised, give me the immune system basics in a quick read. It has simple illustrations to support the text, and has a table of abbreviations — which can be beneficial given the hugely abbreviately nature of the immune system physiology. There is also a “further reading” section, but it’s heavily focused on textbooks – versus presenting popular science books that cover the material in a more light and entertaining manner.

I’d highly recommend this book if you have a basic scientific literacy and want just the facts on immunity without a lot of meandering narrative.

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BOOK REVIEW: Behave by Robert Sapolsky

Behave: The Biology of Humans at Our Best and WorstBehave: The Biology of Humans at Our Best and Worst by Robert M. Sapolsky
My rating: 4 of 5 stars

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This book examines the role of biology in the best and worst of human behaviors – as well as presenting factors that compete with or complement biological explanations, as the author finds relevant. Sapolsky is neuroscientist (specifically, a neuroendocrinologist) with a unique perspective as his research cuts across species – involving not only human beings but also baboons. Sapolsky investigates why humans fight, cooperate, rape and forgive by comparing and contrasting human behavior with what is seen in the animal kingdom.

The first thing a potential reader must realize is that Sapolsky dives into the weeds more so than most scientists writing for a popular audience. This will be a plus if one’s grasp of science (biology, in particular) is strong. However, if the reader hasn’t read anything on biology since high school or freshman year of college, one is likely to find the names and descriptions of hormones and neurochemicals, brain sectors, and protein processes a bit daunting. The book has three appendices that offer primers on neuroscience, endocrinology, and proteins, respectively, to get readers up to speed on the basic science. Furthermore, Sapolsky is quick to point out what can be skipped by readers who don’t want so much detail. I don’t want to give the impression the book is boring. Sapolsky uses humor and story to good effect. It’s just that he gets into Latin names and physiological minutiae at a level that most of his counterparts don’t, and that some readers will find challenging.

While not formally divided so, the seventeen chapters of the book can readily be split in two parts. The first ten chapters discuss the types of behavior that Sapolsky is taking on, and then work back from what happens immediately before a behavior (i.e. one second before) through neuronal, hormonal, and other proximal causes to the far distant causes rooted in human evolution. The first half of these chapters take one to a point in the individual’s life at most months out from the behavior under consideration. Chapters six through eight go back to the individual’s youth, exploring the role of adolescence, infancy, and fetal development. Chapters nine and ten peer back before the birth of the individual to those who contributed indirectly to the individual’s vice or virtue, including the role of the broad run of human evolution. It should be pointed out that this first part is where the aforementioned technical depth is mostly observed.

The second part of the book changes the approach by taking a more topical approach. Said topics include: us/them discrimination, hierarchy (and the acceptance / rejection thereof), morality, empathy, metaphors and symbols that become integral to good and bad behavior, the biology of free will (or the lack thereof,) and consideration of the question of whether humanity is getting more peaceful (as Steven Pinker argues in his book “The Better Angels of Our Nature” [which is arguably one of the main competitors to Sapolsky’s book, though the focus is a little different.]) This second part gets much more into the social science perspective, and isn’t as scientifically dense as the first portion of the book.

I would recommend this book to anyone interested in the good, the bad, and the ugly of human behavior. With the exception of getting a little technical in spots, it’s quite readable and interestingly organized and presented. As one can’t help get into political and cultural norms in a book on human behavior, Sapolsky betrays his personal biases here and there, but is quick to admit when there is evidence against them (or no evidence at all, either way.) I felt he maintained a reasonable scientific objectiveness, but others may feel differently.

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5 Fun Facts about Breathing

Annapurna, Nepal; Taken in May of 2018

5.) The Death Zone may be a myth, or — probably more accurately — everyone may have their own personal death zone:

It’s widely stated as fact that above 8,000 meters (26,000 feet) every human being is dying, no human can acclimatize, and the race is on to get back below that altitude before the body is damaged beyond its ability to repair itself. This hard-limit is widely publicized in reputable, mainstream publications such as National Geographic. There’s a certain logic to such a limit. In response to the diminished pressure of oxygen, the body produces more hemoglobin (that’s acclimatization), but the bloodstream can only take up so much hemoglobin.

Mark Horrell, in his mountaineering blog, challenges the idea of a one-size-fits-all hard limit, and provides anecdotal examples that contradict the 8,000 meter cap.

4.) Sticking one’s face in water allows one to hold one’s breath longer:

Sensory cells in the face and nostrils sense wetness and this sensation triggers a slowed heartbeat (bradycardia) and constriction of blood vessels (vasoconstriction) so as to reduce blood flow to the extremities.

A more detailed explanation can be read here.

3.) Mouth-to-mouth resuscitation works because our lungs only capture about 20% of the oxygen in each inhalation:

If we had super-efficient lungs, our exhalations wouldn’t contain enough oxygen to sustain the patient receiving cardiopulmonary resuscitation (CPR.)

This and many other fascinating respiratory facts can be found on the Crash Course videos on the subject.

2.) In two weeks time the breath you’re exhaling right now will have spread out around the globe.

Sam Kean’s book, Caesar’s Last Breath, discusses this subject in great depth. In fact, the title is a reference to the fact that in each breath it’s likely that one inhales a molecule of Caesar’s dying breath.

1.) When you lose weight, most of it (84%) is lost in exhaled carbon-dioxide:

This may not be a question that ever occurred to you, but I bet you find it fascinating once it’s brought to your attention. It’s not like when you cut 5 kg, there’s a fat pile sitting somewhere. More about this subject can be learned here.

Nadi Shodhana; Alternate Nostril Breathing

BOOK REVIEW: Plyometric Anatomy by Derek Hansen

Plyometric AnatomyPlyometric Anatomy by Derek Hansen
My rating: 4 of 5 stars

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This book performs two tasks at once. First, it’s a guide to the broad range of plyometric exercises and how they can be conducted safely. Plyometrics take advantage of a phenomenon in which rapidly stretched muscles contract more forcefully and rapidly. However, you may recognize them as exercises involving jumping and other explosive movements that are used to build power. (Power being the ability to generate a force in as short a time as possible. This is in contrast to strength — a measure that’s only concerned with the amount of force generated.) I would go as far as to say the book could be useful for many individuals who don’t need any particular insight into anatomy, but who want to learn to do a wide range of plyometric exercises. (That said, if you are said person, you may want to shop around because you may find the one or two drawings per exercise may not be adequate for your purposes, and you may discover you need more guidance if you’re new to fitness activities.)

Second, the book educates the reader about what musculature is used in each exercise, and differentiates the primary movers from the secondary muscles. The book provides a happy medium useful for coaches and trainers. It doesn’t get bogged down in the anatomical and physiological minutiae, but provides enough information for individuals who want to see what muscles are working without drilling down into depths of great precision.

The book consists of nine chapters. Of these, the first two chapters provide fundamental background information. Chapter one examines how and why plyometric exercises work in a general sense. Chapter two gets into more logistical issues such as what equipment is needed (e.g. hurdles and medicine balls), what surfaces are ideal for practice (no small issue considering the loads generated), and how training progressions should be formulated.

Chapters three through eight are the core of the book. These are the chapters that describe exercises as I mentioned above. The first of these chapters presents foundational exercises. Plyometrics tend to be physically intense and so many individuals will need to build capacity before moving straight into a full-fledged plyometric exercise regime. The next five chapters explore (in order): bilateral lower body exercises, unilateral lower body exercises, upper body exercises, core exercises, and combination exercises (e.g. exercises that combine jumps with sprints or medicine ball throws with jumps and so forth.)

Each of the exercise descriptions consists of five parts: an anatomical drawing showing the action and the musculature involved, a description of how the exercise is safely performed, a text list of the muscles involved (divided into primary and secondary muscles as is the drawing), notes exploring unique considerations for that particular exercise, and variations for those who need to make the exercise more or less challenging.

The last chapter investigates injury prevention and rehabilitation. One learns how to evaluate some of the more high-risk behaviors and misalignments that must be corrected for exercises to be done safely. One also learns how a swimming pool can be used to help athletes rebuild their capacity after an injury, as well as how rehab activities can be done out of the pool.

There are graphics throughout the book. For the most part, these consist of anatomical drawings. These drawings show the body in transparent form so that one can see the muscles involved in each exercise. There is a reference section at the end of the book.

I found this book to be informative and thought-provoking, and I’d recommend it for anyone who is seeking to expand their depth of knowledge about exercise science – particularly coaches, trainers, and teachers.

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BOOK REVIEW: The Psychobiotic Revolution by Scott C. Anderson, et. al.

The Psychobiotic Revolution: Mood, Food, and the New Science of the Gut-Brain ConnectionThe Psychobiotic Revolution: Mood, Food, and the New Science of the Gut-Brain Connection by Scott C. Anderson
My rating: 5 of 5 stars

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For centuries there have been cases in which a change in diet –often accidental– led to relief from a mental illness. However, given the sporadic nature of such effects and the complete lack of understanding of microbes, the enteric nervous system (i.e. the gut’s own “brain” that communicates with — but is also autonomous of — our “first” brain,) and the complexity the symbiotic relationships involved, these anecdotal cases had limited influence on the state of medicine. However, recent years have seen an explosion of understanding in this domain. This has resulted in a vast number of books being written on the role of microbes in the gut for overall health, the role that changing diet can have on changing our microbiota, and related topics such as how the overuse of antibiotics can have a deleterious effect on health by tossing out the microbial baby with the bath water. This book touches on all those topics (and more) as it explores the role of our bacterial hangers-on on our mental health.

The book consists of nine chapters. The chapters are organized so as to first present one with the necessary background to understand how changes to one’s gut microbiota can improve one’s health —particularly one’s mental health (though many of the mental illnesses influenced by microbiota are linked to physical ailments)— before moving on to the specifics of what microbes have been shown to have a given effect and what diseases can be influenced by consumption of probiotics.

The first five chapters give the reader an introduction to the topic and an overview of information one needs to know to understand the later chapters. Chapter three gives one an overview of the changing profile of one’s microbiota over the course of one’s life. Particular emphasis is given to one’s youth and to the transfer of bacteria to infants. [Readers may be aware of the problem that c-section births result in a failure of babies to receive a dose of beneficial microbes imparted by passage through the vaginal canal.] Chapter four takes one on a quick ride through one’s alimentary canal from mouth to rectum, with particular emphasis on questions such as how bacteria survive the stomach’s acid bath, and which parts of the digestive system contain which microbes (and to what effect.)

The last four chapters dig deeper into the specifics. These chapters look at specific probiotics, how one can get them into one’s system, and what science has found out about probiotics and psychobiotics (like probiotics, but specifically ones that influence mood and mental states) effects on specific ailments. Chapter eight, which deals with major diseases, does cover physical ailments as well as mental ones because – as mentioned— these afflictions often go hand-in-hand. The last chapter (Ch. 9) looks at where this body of knowledge is going. It delves into practices that are presently well-established, such as fecal matter transplants, but also into challenging works-in-progress such as attempts to develop narrower spectrum antibiotics so that we can get the life-saving benefits of these medications without their crippling side-effects.

The book has many graphics, as one would expect from a work that investigates such a complex scientific topic. I can’t really speak to the quality of the graphics as the review copy I read didn’t have completed graphics. However, the subjects of the graphics seemed appropriate and well-placed. The book also has a glossary, annotations, and a further reading section to assist the reader in the study of this subject.

I found this book to be informative and engaging, and would highly recommend it for anyone interested in the role of microbiota on mental health. The text was well-organized and readable. Given the scientific nature of the material, it’s easy for such a book to become ponderous, but the authors made attempts to keep the tone light and the presentation non-intimidating.

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5 Essential [and Sometimes Hilarious] TED Talks About the Human Body

5.) 3 Clues to Understanding your Brain by VS Ramachandran: Ramachandran discusses three afflictions that offer insight into the working of the brain. Capgras Syndrome occurs when individuals think loved ones have been replaced by impostors. Phantom limbs occur when there is an amputated limb which the brain continues to feel the presence of. Synesthesia is a muddling of sensory inputs /experiences.

4.) Charming Bowels by Giulia Enders: How we poop. How our gut nervous system influences our central nervous system. Why there is such a thing as “too clean for your own good.”

3.) Can We Create New Senses for Humans by David Eagleman: Our senses are narrowly attuned to taking in that information that offered evolutionary advantage to our ancestors. How might technology help us transcend those bounds?

2.) 10 Things You Don’t Know about Orgasm by Mary Roach: Eyebrow orgasm, thought-induced orgasm, orgasm among the deceased, and how orgasm may cure your hiccups.

1.) The Biology of Our Best and Worst Selves by Robert Sapolsky: Sapolsky explains that one can’t look at one biological system to understand violence or cooperation. Instead, genetics, environment, our nervous system, our endocrine system, and even the digestive system come into play. He also considers how we change.

5 Interesting Respiratory Facts for Yoga Teachers

Pranayama (breath exercise) is a crucial part of yogic practice. While I may spend less time on the pranayama portion of my practice than the asana (postural) part on most days, I’ve come to view pranayama as at least as important. (i.e. It packs a lot of punch.) With that in mind, here are a few fun facts about respiration for you your consideration:


5.) Asthma Fact: People in richer countries are more likely to have asthma, but–within more wealthy countries–poor people are disproportionately effected. (Asthma is a condition in which lung tissue becomes inflamed, and thus it’s hard to breath.)

Source: Krucoff & Krucoff. 2000. Healing Moves. New York: Three Rivers Press. p. 288

Yogic Relevance: There’s at least some preliminary evidence that yoga practice can benefit asthma patients. Mekonnen, D. & Mossie. A. 2010. “Clinical Effects of Yoga on Asthmatic Patients: A Preliminary Clinical Trial.” Ethiopian Journal of Health Science. Vol. 20(2). pp. 107-112.


4.) Altitude Fact: At the summit of Everest, atmospheric pressure is about 30% of what it is at sea level.

Source: Coulter, H.D. 2001. Anatomy of Hatha Yoga. Allahabad: Himalayan Institute India. p. 96.

Yogic Relevance: The slow deep breathing you sometimes teach in pranayama courses could be a life-saver. Bilo G. et. al.  2012. “Effects of Slow Deep Breathing at High Altitude on Oxygen Saturation,” Pulmonary and Systemic Hemodynamics. PLoS ONE. Vol. 7(11): e49074.


3.) Lung Fact: If one extracted, flattened, and laid side-by-side the 300 million alveoli of the average person’s lungs, they would cover an area greater than the average one bedroom apartment. (Alveoli are the little sacks at the end of the bronchioles where oxygen and carbon dioxide are exchanged.)

Source: Hymes. A. 2009. “Respiration and the Chest: The Mechanics of Breathing.” in Science of Breath: A Practical Guide by Swami Rama. Honesdale, PA: The Himalayan Institute Press.

Yogic Relevance: Vital capacity (total amount of air one can breath in and out of those little sacks) is increased through yogic practice. Karthik, P.S. et. al. 2014. “Effect of Pranayama and Suryanamaskar on Pulmonary Functions in Medical Students.” Journal of Clinical and Diagnostic Research. Vol. 8(2). pp. BC04 -BC06.

Note: there has been confusion about the degree to which yoga helps VO2 max (maximum oxygen utilization), at least in comparison to other forms of exercise, because there has been mixed results in the literature. The consensus seems to be the effect–if any–isn’t large compared to cardiovascular exercises. The strength of the pump (i.e. the heart) seems to have more to do with this particular measure than the lung’s holding capacity. While VO2 max is an important measure for athletes, the fact that it may not be improved by yoga doesn’t mean yoga doesn’t offer many fine benefits for athletes. As I recall, this is dealt with at length in Broad’s book (i.e.  Broad, W.J. 2012. The Science of Yoga: The Risks and Rewards. New York: Simon & Schuster.)


2.) Nose Fact: Rhinologists (doctors specializing in noses) figure that the nose has around 30 functions in the breathing process (e.g. moisturizing and warming air, catching foreign matter, directing airflow, and much more.)

Source: In the aforementioned Swami Rama book Science of Breath in a chapter entitled, “Following Your Nose: Nasal Function and Energy” by Rudolph Ballentine, MD.

Yogic Relevance: Alternate Nostril Breathing (Nadi Shodhana) is shown to tone the parasympathetic nervous system (PNS, i.e. the part of the autonomic nervous system involved in rest & digest functions.)  Sinha, A.N., et. al. 2013. “Assessment of the Effects of Pranayama / Alternate Nostril Breathing on the Parasympathetic Nervous System.” Journal of Clinical and Diagnostic Research. Vol. 7(5). pp. 821-823.


1.) Pace Fact: At about 5 breaths per minute, most people’s thinking is clearer than usual.

Source: Brown, R. & Gerbarg, P.2012. The Healing Power of Breath. Boston: Shambhala Publications.

Yogic Relevance: The breath is our most powerful tool for controlling the mind. Vindicated!

5 Physiological Fun Facts for Yoga Teachers and Practitioners


5.) FACT: People who lose weight often still feel heavy and commonly maintain the body language and movement characteristic of an overweight person.

REASON: A conflict exists between the body schema (which is largely up-to-date on the current state of the body, but is largely unconscious) and body image (which relates to how we feel about our bodies, can lag behind the state of the body, and of which we are conscious.)

RELEVANCE: It may take unconventional activities to help a student realign his or her body schema and body image. e.g. Wobble boards have been shown to be effective.

REFERENCE: “The Body Has a Mind of Its Own” by Blakeslee and Blakeslee


4.) FACT: The busiest skeletal muscles in the body are the extraocular muscles (i.e. more than 100,000 moves per day.)

REASON: We don’t see over a broad area as clearly as we think we do. The illusion that we can is created by rapid saccades by which the eye is constantly moving to take in sights from the point at which our sight is best. You can prove this to yourself by fixing your gaze forward, and then–from the side–draw a playing card at random so the face is towards your cheek while holding the card out to one’s side at shoulder height, and then–eyes still fixed forward–gradually move it in an arc at arm’s length towards one’s center-line until you can make out which card it is. You might think you’d be able to make it out at say a 30-degree angle from center-line, but you’ll find it’s almost directly in front of your eye when you can make it out. If if isn’t: a.) your eyes made a cheating saccade so quickly you didn’t notice it or, b.) you are an android and have eyes (and nervous system interface) that aren’t constructed on the same principles as the human system of vision.

RELEVANCE: One may want to brush up on eye yoga. Yes, there is such a thing.

REFERENCE: There’s a section on exercises for the eyes in Swami Saraswati’s “Asana Pranayama Mudra Bandha” (commonly called APMB.)


3.) FACT: The gut has its own nervous system (i.e. the enteric nervous system) that can interact with our body’s nervous system, and increasing evidence suggests that it’s not always mental stress that causes stomach aches, but sometimes problems in the gut result in mental / emotional turmoil.

REASON: There’s a lot that remains unknown at the moment, but a lot of research is going on in this area. It seems reasonable to guess that there’s probably an evolutionary advantage for the digestive tract to be able to express its dissatisfaction in a way that changes behavior (and emotions are all about behavior change.)

RELEVANCE: Unexplained depression or emotional outbursts may have unexpected origins.

REFERENCE: I can highly recommend “Gut” by Giulia Enders, but I’ve also heard great things about the more recent “I Contain Multitudes” by Ed Young, though I haven’t gotten around to reading it yet myself.


2.) FACT: The problems that can arise due to hyperventilation aren’t about oxygen levels, they are about too little carbon dioxide.

REASON: Lack of carbon dioxide can cause arteries and arterioles of the brain and spinal cord to constrict.

RELEVANCE: Introduce kapalbhati and bhastrika with caution.

REFERENCE: H. David Coulter’s “Anatomy of Hatha Yoga” chapter on breathing (Ch. 2) deals with the physiology of breathing in an excellent fashion.


1.) There are oh-so-many more than five senses in the human body. Within the realm of “felt sensation” alone there’s not only touch (one of the five senses we usually think of), but also: thermoception (sense of temperature), nociception (sensation of pain), proprioception (sense of the location and motion of our various body parts, and balance (which relies on vision and proprioception but also vestibular sensation.)

REASON: Without these sensations we couldn’t function as we do. I don’t have to tell experienced meditators how difficult it can be to simply stand up or walk when proprioception is dampened by the pins-and-needles from sitting cross-legged such that one doesn’t notice one’s drooping foot.

RELEVANCE: At some point one should begin to practice relying on proprioception more and visual confirmation less. (Proper drishti–focal points–rarely allow one to visually confirm one’s position.)

REFERENCE: Besides the book mentioned in #5, check out David J. Linden’s “Touch.” I’ve also begun reading a Harvard Medical School Guide entitled “Better Balance” that gives insight into how to improve the sense of balance–particularly if one serves senior citizen students.