Tag Archives: Physiology

BOOK REVIEW: Body Am I by Moheb Costandi

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Body Am I: The New Science of Self-ConsciousnessBody Am I: The New Science of Self-Consciousness by Moheb Costandi
My rating: 5 of 5 stars

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In this book you’ll learn about: a man who wanted a perfectly healthy leg amputated, a fisherman who felt like his hands were crab claws, a woman who felt she wasn’t responsible for the actions of her hand, various people who’ve experienced “Alice in Wonderland Syndrome” [i.e. feeling one has shrunk or stretched,] and about many other issues stemming from the body’s sensory and motor integration with what we think of as the mind. For most of us, the most powerful take-away to be gained from this book is just how wonderful and awe-worthy it is that we have bodies that are so well integrated and coordinated that we can go about life engaging in all sorts of fascinating and productive activities.

While this isn’t the only book that addresses this subject, I think it’s a topic worth learning more about and reflecting upon in depth. We can get so out of touch with the fact that our body is integrated with our mental and sensory experiences that we take “brain in a vat” scenarios as a given for the near future, as if one is the sum of one’s neuronal connections. This book will disabuse one this notion. In fact, the final chapter (Ch. 10) questions the proposition that copying consciousness is a matter of mastering such neuronal mapping. It’s easy to miss how much of our emotional experience is rooted in what’s happening in our guts and heart, and how much all the non-central nervous system parts of the body play in our conscious experience of the world.

I learned a great deal from this book and would highly recommend it.

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BOOK REVIEW: The Exquisite Machine by Sian E. Harding

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The Exquisite Machine: The New Science of the HeartThe Exquisite Machine: The New Science of the Heart by Sian E. Harding
My rating: 5 of 5 stars

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Release date: September 20, 2022

Get Speechify to make any book an audiobook

In this book, a renowned heart researcher presents an overview of what we know (and don’t know) about the human heart: i.e. what can go wrong with it and why, how [and to what degree] it fixes itself, and what modern medicine can do to treat or replace a damaged heart. I learned the most from the middle of the book – i.e. chapters five through seven. Chapter five explores plasticity in the heart, plasticity is a concept that most people associate with the brain and its ability to rewire itself to contend with damage or changing needs. The other two chapters look at how the heart can be damaged, specifically as a result of emotional experience. A “broken heart” isn’t necessarily a misnomer.

Chapter four is also intriguing but takes the win for “which one of these things is not like the others.” It deals with big data, though not in a general sense but rather as it applies to gaining a better understanding of the heart. This chapter discusses a common challenge of medical research: that it’s hard to come up with large enough study groups of patients with close enough to the same problem to draw solid conclusions. Four also discusses the potential of the vast amount of data that exists, e.g. Fitbit heart rate figures.

The last couple chapters deal largely with the future of heart repair through genetic / biological means (as opposed to via mechanical hearts and technologies, which are dealt with in Chapter nine.) This is where the book gets to be a challenging read for a readership of non-experts. It gets technical and jargon- / acronym-heavy.

The heart is an astounding entity, relentlessly at work, rarely giving up despite regularly being subjected to intense shocks, an organ tied to our whole being in a way that humans have always felt – if only just begun to understand. If you’re interested in learning more about this magnificent organ, check this book out.

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BOOK REVIEW: The Physiology of Yoga by Andrew McGonigle & Matthew Huy

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The Physiology of YogaThe Physiology of Yoga by Andrew McGonigle
My rating: 5 of 5 stars

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This is a much-needed book for two reasons. First, while there are a number of fine books on anatomy as it applies to yoga, such books focus on the musculoskeletal system, occasionally venturing into the respiratory system – re: pranayama (breathwork.) However, yoga anatomy books rarely giving an overview of the workings of the body as a whole or describe how yoga influences and is influenced by other bodily systems. This book systematically reviews not only the muscles, bones, and lungs, but offers insight into the less familiar systems, such as the lymphatic, immune, and endocrine systems. Unless you want to know more about yoga and the integumentary system (skin, hair, and nails,) this book has got you covered. The book does an excellent job of avoiding muddling science with mythological beliefs about the body, a common sin among yoga books.

Second, there are many physiology misunderstandings and mistakes that are widespread and have come to be repeatedly parroted by new generations of teachers. These range from ideas that are unsupported by scientific evidence to those that are completely in conflict with well-understood science. This book has text boxes throughout that investigate widely taught physiology myths (e.g. twists detox the liver, shoulder stands stimulate the thyroid & pineal glands, kapalbhati (forced exhalation breathing) stops the aging process, heavy sweating detoxifies the body, and various claims about specific asana / practices curing specific ailments.) These boxes review what studies have been done on each claim, and (in the absence of scientific literature) it discusses whether claims make any sense in light of well-established physiological science.

The book is clear and easy to read, and has well-drawn anatomical drawings and diagrams to help communicate the workings of the body. It also has an extensive bibliography of works referenced.

The book wasn’t perfect. I thought the last chapter, which is a collection of yoga sequences, was out of place and unnecessary, given the objectives of this book. I suspect its inclusion was solely to remind readers flipping through the book that they were reading a book about yoga as well as physiology. (The graphics and headings don’t necessarily scream yoga.) However, I think this could have been more relevantly and effectively by including more graphics throughout that show individuals engaged in yogic practices / asana, or – alternatively – focusing on the physiological aspects of the practices and sequences in the last chapter. There was also a place or two where I wasn’t sure what the authors were saying, not because they didn’t write in a clear and readable style or because what they were saying wholly conflicted with what I understood to be true, but just because there was enough ambiguity that I was left puzzled.

Overall, I’d recommend this book for yoga teachers and practitioners looking to expand their understanding of the workings of the human body, and to liberate themselves from some misinformation that has gained a following.


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BOOK REVIEW: Life at the Extremes by Frances Ashcroft

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Life at the ExtremesLife at the Extremes by Frances Ashcroft
My rating: 5 of 5 stars

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Anyone interested in the limits of human physiology will find this book fascinating. Technically, its subject matter is broader than that, considering the environmental limits of living creatures, generally. However, all but the last chapter focuses on how humans react to (and adapt to) extreme conditions. Chapters one through six explore the challenges and limitations of humans under extreme conditions of elevation (ch. 1,) of pressure [underwater] (ch. 2,) of heat (ch. 3,) of cold (ch. 4,) of intense physical activity [running-centric, but deals with strength and power as well] (ch. 5,) and in space (ch. 6.) Then, each chapter reflects upon examples of species that are extremely well-adapted to said conditions, and why. (e.g. After learning about how and why humans have to acclimate to survive high elevation treks, one learns about the bar-headed goose, a bird that can go from sea level to flying over Everest – all in the same day.)

The final chapter (ch. 7) is a bit different in that it discusses extremophiles, creatures that can survive in a wide range of conditions (e.g. acidity, temperature, lack of moisture, lack of oxygen, etc.) that would be certain death not only for humans but for any animals. Most of the species discussed are either single-celled creatures or tiny multi-cellular life (e.g. Tardigrades.) With respect to humans, there is a discussion of the limits and present understanding of suspended animation.

This book offers an intriguing look at life at the extremes. While written by a Professor of Physiology, it’s highly readable for a general audience. It mixes narrative examples in with the discussion of physiology to make the material approachable and engaging. I’d highly recommend this book.


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BOOK REVIEW: Drunk Flies and Stoned Dolphins by Oné R. Pagán

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Drunk Flies and Stoned Dolphins: A Trip Through the World of Animal IntoxicationDrunk Flies and Stoned Dolphins: A Trip Through the World of Animal Intoxication by Oné R. Pagán
My rating: 5 of 5 stars

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Humanity’s proclivity to think ourselves above nature has led us to miss the fact that we aren’t the only intelligent creatures and that we share more in common with the rest of the animal kingdom than – perhaps – we’d like to think. Science’s recognition of this truth has spawned a vast collection of books on animal (and, for that matter, plant) intelligence as well as the other traits we share in common with different species. This book carves out an interesting niche in this literature by discussing how other creatures use psychoactive substances (i.e. what we think of as “drugs and alcohol.”) While people tend to think that we are alone not only with respect to intelligence, but also with respect to our vices, it turns out this doesn’t seem to be the case. Of course, there’s a lot we don’t know about dolphins that play with blowfish or monkeys on magic mushrooms – e.g. what their internal experience of the substance is like, and to what degree consumption is purposeful versus accidental, but there is an increasing number of studies that suggest other species use drugs, and like it. The book also delves into the role plants play, particularly in producing substances that have psychoactive effects.

This book is humorous (the material is certainly there) and intriguing. It’s an easy pop science read, and avoids becoming too bogged down in the minutiae of biochemistry. That said, it does include graphics, such as chemical diagrams of psychoactive molecules, and does have to dip its toe into concepts of biology and chemistry. If you find the topic intriguing, you should give it a read.

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

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

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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

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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

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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

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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

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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

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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