The Body: A Guide for Occupants
5 things I learnt from Bill Bryson's Book, The Body: A Guide for Occupants
If you’d like to listen to this, instead of reading it, you can find an audio version here.
When I think about the human body, I marvel at its complexity. There’s so much going on within it that when functioning well, it allows us as humans to do so many things and experience this crazy life we all get. It’s a marvel of creation, and something I imagine that most of us don’t fully understand. For example, why do you think babies have such round and cute-looking tummies? It’s not because they’re fat or they’ve eaten lots. It’s actually because, as infants, our livers are disproportionately sized, and so it makes babies’ tummies look massive, taking up loads of room in that region of the body. There’s so much complexity, nuance and wild bits of science and evolution that it’s probably natural we don’t fully understand how our bodies work, or why things are the way they are. Aware of this, Bill Bryson wrote a book called The Body: A Guide for Occupants, with the aim of educating people more about the body in which we inhabit. A few months ago, I read this book, and I want to share my top 5 things I learned from this book. I also really recommend you read this book yourself, as you will likely learn loads of other things about the human body!
The Impact of Gravity
Have you ever thought about gravity’s impact on people of different sizes? I know I hadn’t really considered it until Bill Bryson mentioned it. In a chapter all about equilibrium within the body, he talks about how humans can scientifically only really be the size we are. If we started growing much bigger, all our proportions would be out of whack, and particularly our bones - although they may scale in size, they wouldn’t continue to grow in strength, which would be a problem as we grow heavier and heavier. But this wasn’t the thing that caught my attention here. Bryson then throws out this random idea:
“It will not have escaped your notice that a small bug that falls off a tabletop will land unharmed and continue on its way unperturbed. That is because its small size (strictly, its surface area-to-volume ratio) means that it is scarcely affected by gravity. What is less well known is that the same thing applies, albeit on a different scale, to small humans.” - p223
The severity of a fall is impacted by 3 things: the mass of the falling object, the velocity at which it is falling, and the distance it is falling. Basically, the smaller and less something weighs, the more significant the force with which they collide with the floor, or anything else they fall against. It’s why babies who are learning to walk, or small children running around, seem so resilient to their falls - they simply just don’t get hurt as much or have as big an impact as if an adult had fallen over in that way.
This is something, if I’m honest, I haven’t often thought about. But this really stood out to me as someone who now has a baby. It particularly stood out to me in the case of head injuries. My daughter always seems to be hitting her head on things, whether she’s crawling around and not looking where she’s going, or trying to stand up while holding onto things and toppling over, now she’s even trying to walk. Often she plummets to the ground, headfirst, or close to that. I’ve always thought that if I fell over that much, I’d do myself some proper damage, but it’s kind of assumed that babies are just resilient; as Bryson points out, it’s actually physics which explains it.
The difference is so extreme that Bryson states that if a child, half my height, which is still currently taller than my daughter, falls and hits their head, they only experience 1/32 of the force that I would experience doing the same thing. That is a staggering difference in force. But it also applies to animals, maybe it’s why cats are so durable in the way they have 9 lives and always land on their feet, they just are small and take much less force on impact. There’s going to be so many examples, and I found this such an interesting bit of science.
The brain exists in a silent, dark box
When talking about the brain, Bryson expressed an idea that I’d heard before in another book: the funny thing about the brain is that it processes and creates a magical world in which we experience, through our senses (as well as things it makes up too), but in reality this organ which does all this exists in what Bryson describes as a “silence and darkness, like a dungeoned prisoner”, or as Will Storr puts in The Science of Storytelling: “the silent, black vault of our skulls”. This is a paradox for Bryson, that the organ which provides us with all the information we know about the outside world has never itself experienced it.
The world we experience, the potential colours, sounds and smells, is all created by our brains. It’s fed information, pieces of a puzzle, by our eyes, our ears, our noses and all the rest of our body, but it’s the brain which pieces it all together, making the world we experience. There are billions of brain cells working hard to make our reality. But some question whether it is actually the reality the brain creates, or whether it’s a hallucination of reality. Storr argues this:
It feels as if we’re looking out of our skulls, observing reality directly and without impediment. But this is not the case. The world we experience as ‘out there’ is actually a reconstruction of reality that is built inside our heads. - p21
He goes on to argue, with the help of neuroscientist David Eagleman, that we don’t actually experience the full reality of the world around us, that although our brain is fed information through our senses, that is limited and only partial information. There are bits of reality that we just don’t experience, there are bits that we misunderstand, and even more interestingly, this organ that sits within this black vault that is our skulls, unseeing, actually makes things up. Storr describes it as our hallucination of reality, that in every moment our brain is predicting what a scene should look, feel and sound like. Based on previous experiences, based on what our senses are feeding it, and then it generates a hallucination based on these sensory inputs and these predictions. It’s why we can be in the same place, looking at the same thing, in theory experiencing the same reality - yet each of us can experience it in a different way because our unique brains are creating a unique story from within their dark prison.
It’s kind of sad when you think about it that the brain never gets to see the light of day. Like a person trapped in a room, only experiencing the outside world and people through screens, the brain, which plays the main character of our lives, is trapped, only experiencing a second-hand reality that is distorted and missing pieces.
C-sections vs Vaginal Births
C-sections are becoming more and more popular, to the point where soon they might become the primary means of babies being born. For anyone who is unaware, a C-section is a major operation where an incision is made across a woman’s tummy and womb, and then the baby is removed from the womb, instead of it coming out through the vagina.
There are lots of reasons C-sections happen, many are medical emergencies, such as if the baby is in the wrong position and it might be really hard or impossible to get them out normally, if the baby or the mothers lives are at risk through labour and birth, or some other medical illnesses that make labour dangerous. Nowadays, C-sections aren’t just reserved for emergencies; they can be planned - whether for medical reasons or now even personal preference. All of this means the number of C-sections is growing rapidly. As of when this book was written, 2019, one-third of births in the USA are c-sections, and it’s nearly a quarter of births in the UK. These numbers, I can only imagine, have risen since then.
Bearing this in mind, Bryson shares some really interesting data and research about C-section births. He says:
Various studies have shown that people born by C-section have substantially increased risks for Type 1 diabetes, asthma, coeliac disease and even obesity, and an eightfold greater risk of developing allergies. - p348
But why is this? Bryson states that we are only beginning to understand this phenomenon, and only really starting to understand the vaginal microbiome, but the basic premise is this: A microbiome is a collection, or community of microorganisms that exist in a particular environment. Within humans, this community exists within different parts of the body, and we are slowly learning that there are many microbes within these communities which serve amazing functions for us. The most well-known example is the microbiome in our gut, of which there are microbes which help do the essential function of breaking down food.
Although we don’t yet know as much about the vagnial microbiome, the theory based on the research so far suggests that it might be as unique and incredible as breast milk. Breast milk is a perfect evolutionary design, with each mothers being unique and serving their baby specifically with the right calories, nutrients, and even can stave off illness and things like that. It’s thought that each woman’s vaginal microbiome will be unique and will be passed on to the baby. As it passes through in those final moments of birth, a unique and powerful community of microbes, which seems to have a massive influence on long-term health, will flood the baby’s skin and start building the baby’s immune system and more. There was a suggestion that this microbiome also had a significant impact on the baby’s gut microbiome, but after more research has been done, it’s become clear that this isn’t exactly the case and that the gut microbiome will develop almost identically, whether a baby is born vaginally or not. It might just take a little longer.
Now, this doesn’t mean any baby born by C-section is doomed, at least I hope not; I was born by C-section. Remember, the research only shows an increased risk, not a guarantee. There are still many other factors at play. However, it is a really interesting fact with this trend of increasing C-sections and definitely an important factor that immediate health risks trump, but mothers should definitely consider and be aware of.
Teenagers and Dopamine
It’s well known, or at least I think it should be, that being a teenager is hard. It’s a time of life when you have hormones raging inside of you, pulling you all over the place, in an exhausting and often inconsistent pattern. You are more prone to taking risks, as you explore and adventure, yet you are often criticised for this evolutionary trait. And in the midst of all that, you’re meant to be working out who you are and starting to define your future adult life. Being a teenager is hard.
Something Bryson revealed to me within his book, which fascinated me, is that during adolescence and the teenage years, the body produces more dopamine than at any other time of life. He says:
At the same time, the body produces more dopamine, the neurotransmitter that conveys pleasure, than it ever will again. That is why the sensations you feel as a teenager are more intense than at any other time of life. But it also means that seeking pleasure is an occupational hazard for teenagers. - p74
Teenagers are flooded with dopamine. The highs are higher than at any other time of life, dopamine-producing activities are more addictive than they ever will be, and teenagers are driven by this to seek out dopamine-producing, pleasure-seeking activities. It’s no wonder that in 2026, teenagers are addicted to social media, video games and vapes. They are all huge dopamine stimulants. This also explains why teenagers tend to take part in risky behaviour - they are seeking out these huge dopamine highs.
This made me think, though, if they are producing more dopamine than any other time of life, although that may, in theory, mean lots of pleasure in life, I’ve learned recently that the body likes equilibrium, especially when it comes to pain and pleasure. Anna Lembke talks about this in her book, Dopamine Nation, how within our body there is a two-sided scale, always trying to balance pain and pleasure. So when we have spikes in pain, we are driven to seek out dopamine and pleasure-inducing activities. Equally so, when we experience pleasure, the body flushes out dopamine quickly, often accompanied by pain of some sort, to gain equilibrium. I wonder whether this means that, as teenagers are prone to experiencing huge doses of dopamine, and the pleasure it comes with it, they are also exposed to huge doses of the other side of the scale, painful experience, emotions, and the constant swinging between those states as the body fights for equilibrium.
I wonder whether this could be one of many reasons why teenagers are also so vulnerable to things like poor mental health, being sensitive emotionally, and generally just feeling like life sucks a lot of the time. They may be driven by the craving for these dopamine highs, to consume these dopamine-producing activities, but the body quickly equalises these feelings, bringing emotional turmoil with it.
Exercise is really good for you. Who’d have thought?
In many sports nowadays, there is a term that people use to describe some of the best players. It’s the term GOAT, meaning greatest of all time. In football, they might use it to describe Messi, Pele or Maradona. In basketball, people might say Michael Jordan. In Tennis, now people would probably say Djokovic. I think it would be fair to say that exercise is the GOAT activity any human can regularly do to look after their health, and I think Bill Bryson would agree. He says:
As well as strengthening bones, exercise boosts your immune system, nurtures hormones, lessens the risk of getting diabetes and a number of cancers, improves mood, and even staves off senility. As has been noted many times, there is probably not a single organ or system in the body that does not benefit from exercise. If someone invented a pill that could do for us all that a moderate amount of exercise achieves, it would instantly become the most successful drug in history. - p209
Exercise is the GOAT.
A moderate amount of exercise, say going for regular walks and getting your heart rate up a little, can reduce the risk of heart attacks and strokes by 31 per cent. Being active for around eleven minutes per day, which by the way really isn’t a lot, can add 1.8 years to your life expectancy. An hour a day can add 4.2 years.
The thing is, some people won’t care about potentially adding those few additional years to the end of their life. Instead, their focus is on the here and now, living well in the life they have now, right in front of them. The great thing is, exercise can contribute significantly towards that. When we exercise, we release endorphins, which are chemicals produced by the brain that do things like improve our mood, reduce feelings of stress and relieve pain. This is an instant way to improve your life today. It’s one of the reasons daily exercise is so good. But it’s not just the endorphins; regularly exercising builds up your stamina and therefore increases your energy levels. As Bryson writes, it increases the strength of our immune system - meaning we won’t be ill as much, a massive win for our quality of life.
Exercise, ultimately, is also fun; humans are designed to move and be active. And the great thing about exercise is that there are loads of ways in which to do it. Running may now be a really popular thing, but it doesn’t mean it has to be your thing. Team sports might be a better option, cycling, walking, dance, or swimming might suit you better, and you might enjoy them more. It’s just about working out what you find fun and engaging, what you can keep doing on a regular basis, for the sake of enjoyment and also the benefits of it. There is an almost unlimited list of ways to move your body and be active, all of which act like the pill that Bryson describes: helpful for everyone and the most successful drug in history. The GOAT activity for human health.
If you haven’t already been convinced, I would wholeheartedly recommend you read Bill Bryson’s The Body: A Guide for Occupants. I have literally scratched the surface, giving you five things that stood out to me in an ocean of thousands of things you could learn from this book.
References
Bryson, Bill. 2020. The Body: A Guide for Occupants. N.p.: Transworld Publishers Limited.
Lembke, Anna. 2023. Dopamine Nation: Finding Balance in the Age of Indulgence. N.p.: Headline.
Storr, Will. 2020. The Science of Storytelling. N.p.: William Collins.