In this interview, we discuss Hayes’s book Sweat: A History of Exercise and look at the importance and development of human movement through the ages. Enter the giveaway below to win a hardcover copy of Sweat (available to U.S. residents only).
Greg: Can you tell me a little bit about your background?
Bill: I’m a writer and photographer living in New York City. Sweat: A History of Exercise is my seventh book. And it’s my fourth book that mixes scientific or medical history with memoir. My first three books kind of had a similar format. I wrote a book called Sleep Demons, which is a memoir about insomnia but also looks at the history of sleep science, and a book called Five Quarts, which looked at blood and the history of human blood—especially in the context of the AIDS pandemic of the 1980s and 90s in San Francisco.
And then I wrote a book called The Anatomist, which is probably the closest thing to Sweat. The Anatomist tells the story behind the classic nineteenth-century text Gray’s Anatomy. For that book, I did research on Henry Gray, the author of Gray’s Anatomy, and the illustrator, Henry Carter. But I also spent about a year studying anatomy alongside first-year med students and going from never having seen a cadaver to doing full cadaver dissection. And the only reason I mention that is that it really prepared me for the work I did on Sweat, which was both archival research and following the evolution of exercise over two millennia, but also looking at individual forms of exercise and trying as best I could to explain to the reader the dynamics of human movement, as I, myself, tried different forms of exercise.
Greg: How did you become interested in the history of exercise in the first place?
Bill: Well, I’ve always loved to work out, to exercise. It’s sort of changed over the years. But I still love to work out. In fact, I worked out at the gym today, did a little upper body workout, got on the Stairmaster and sweated for twenty-five minutes. And I was actually on a Stairmaster—no joke, about ten or eleven years ago—I was on a Stairmaster just about to punch in my program and for some reason, I paused. I looked out at the gym floor, at all these people, men and women, of all different ages and sizes, doing bench presses and curls and pull-ups and push-ups and yoga. And I thought, how did we all end up here? How did we end up in gyms? And if I were to trace a line backward in time, where would I land? Where did this start?
So I got off the Stairmaster and went to the public library because I was sure there must be a book on the history of exercise. And there wasn’t. There have been some academic books on it, of course, and papers and so forth, but nothing exactly like what I had in mind. But the idea took years to develop. It wasn’t until I won a Guggenheim Foundation Fellowship in 2013 that I really began to dig into the subject. I was able to travel, particularly in Western Europe (Italy, France, England, Sweden), and to India, and do research on the history of exercise.
So I have a natural interest in exercise, and then I’ve always had an interest in the human body and the history of medicine, the history of science. I think if I had done better in chemistry and biology in high school, I might actually have become a doctor. But that wasn’t my path. Instead, I’ve been able to explore things that interest me in my books.
Greg: A lot of Sweat deals with a person named Girolamo Mercuriale. Who was he and what was his contribution to the history of exercise?
Bill: Well, I should tell you that when I started my research, I’d never heard of him. He was, and in a way he still is, virtually unknown. But I went to a very special library here in New York City at the New York Academy of Medicine. It’s a wonderful library with a small rare books room. I’d reserved some books in advance by Hippocrates and Aristotle and Philostratus and others, and the librarian added another book to the cart as she rolled it out to me. And she said, “I think you’re going to want to look at this.” It was Mercuriale’s 1569 book De Arte Gymnastica, which is now considered the first comprehensive illustrated book on exercise.
I was thrilled. I’d never heard of him. And I carefully pulled the book—a first edition in perfect condition—out of the case and happened to open it up to an illustration of two pairs of naked men wrestling. It was captivating. But then I turned the page and realized that the entire book, which was very large, was written in Medieval Latin. I couldn’t read it. But some light bulb went on, and I knew I had to find out more about this book and this physician from the Renaissance.
I tracked down the English translator, and it sort of set me off on the journey. So Mercuriale became the main historical figure in Sweat, and I used his book and his life as kind of a jumping-off point. But of course, I wrote about as many other historical figures as I could.
But I was fascinated by Mercuriale’s life story. I should add that De Arte Gymnastica, which is “the art of gymnastics” or “the art of exercise,” is hardly the only book he wrote. He was very brilliant. And he wrote some groundbreaking books on obstetrics and dermatology—fifteen or more other books—though all of them in Latin, so many of them remain unknown to most people.
He was the personal physician to the very prominent and also very wealthy Cardinal Farnese in Rome. In that position, he had access to the Vatican Library and the Farnese family private library. So he was able to dig up these ancient Greek and Roman texts, whether by Hippocrates or Plato or others, about exercise, but also just about the body and about health and well-being and translate them and use them as his main source for De Arte Gymnastica. And it was his aim, an ambitious aim, I should say, to quote, “revive the ancient Greek art of exercise.”
Greg: Looking at De Arte Gymnastica today, how much of the writing or the illustrations would we recognize as exercises we perform now, or as sort of predecessors of modern exercises, and how much is completely foreign?
Bill: Mercuriale did write about every form of exercise known at that time. And so conveniently, there are individual chapters on walking, running, swimming, wrestling, boxing, rowing, and even forms of exercise in his mind that we might not consider exercise, such as laughing or crying, because these actions move the innards of the human body. Now, what is not included in his book are things that were not invented, like the bicycle, which didn’t come into existence until the nineteenth century. Nor did he write about yoga, which existed in the East, but I don’t think he knew about it.
Now, what is his advice like? You should know that Mercuriale definitely wrote De Arte Gymnastica from the perspective of a physician. So it’s very prescriptive in a way. And all in all, his advice is quite sensible. However, his understanding, like everyone’s understanding, of the human body was not accurate. We’re talking about the sixteenth century, when they still believed in the completely fantastical theory of the four humors, according to which the body was composed of, or operated by, these four humors—blood, bile, yellow bile and black bile—and that the humors had to be kept in balance. So when he writes about exercise, he’s always writing about how an exercise will affect the humoral balance.
It really wasn’t until the seventeenth century with William Harvey’s discovery of the circulation of blood by the beat of the heart that doctors and laypeople began to really understand how the human body works, and that there wasn’t such a thing as the four humors. One of the main reasons for the lack of understanding is that cadaver dissection was forbidden for centuries. Galen and Hippocrates and others way back in antiquity really never had the chance to dissect a body and understand that the blood is circulated by the beat of the heart. But when I read De Arte Gymnastica, I already knew about the four humors, because I’d written a book about blood and a book about anatomy. So William Harvey’s discovery in the 17th century was crucial.
They did have an intuitive understanding that exercise is good for the body and the mind and the soul. They all recommended exercise.
Greg: I want to go back a little bit further to Plato and Aristotle and the ancient Greeks. What do you think has been the most significant change in thinking about exercise since that time? And do those changes relate to cultural changes over those millennia?
Bill: The very first thing that comes to mind is that in antiquity, women and girls were not allowed or encouraged to exercise. Except for one place, which I’ll mention, exercise was really a pursuit for men and boys of the upper classes. And there were gymnasia in ancient Greece and Rome. In fact, there were gymnasia in virtually every town. Men and boys exercised in the nude. What has changed? Well, we don’t exercise in the nude anymore. And technology has changed so much in how we exercise, but also in our scientific understanding of the human body.
One thing I really enjoyed when studying Hippocrates or Plato or Galen or Mercuriale was that they did have an intuitive understanding that exercise is good for the body and the mind and the soul. They all recommended exercise. And one theme that runs through the writings of all those great thinkers was moderation, to exercise in moderation. So you find Philostratus and Galen and Mercuriale coming out hard against those who are the ancient equivalent of bodybuilders, who had sort of hypertrophied bodies. The recommendations were quite sensible: to exercise moderately, to get the heart racing, and to work up a sweat.
So what has changed? I mean, women and girls are obviously very much encouraged to exercise. That really changed, though not until the 19th century. One of the frustrations I had working on the book was finding those pockets of history where women and girls become part of physical and exercise culture. And then we have all the new technological equipment. I mean, just being at the gym today and doing the Stairmaster or riding a bike, whether a stationary bike or a bicycle. But some of that ancient advice was pretty sensible. And that surprised me, and I really love that.
Greg: Why were women and girls in ancient Greece not allowed to exercise? Or how was exercise restricted for them?
Bill: Well, I think culturally, there’s such a divide between the genders. The one place where women and girls were encouraged to exercise and where it was very much part of the culture was Sparta. In roughly the tenth century BC, Sparta was a Greek state whose whole culture really was devoted to and defined by warfare. Exercise was a form of training for hand-to-hand combat and warfare. Women and girls were expected to be part of that as well, whether to be warriors themselves or, quite frankly, to be healthy women to bear male children who would be warriors as well.
But that’s one of the few spots in the ancient world, at least in the West, where women and girls were very much encouraged to exercise. You do find a philosopher like Plato saying that women and girls should exercise too, but that was not the reality of everyday life. It was definitely the preserve of men and boys of the upper classes.
Greg: Let’s return to exercise today. Based on what you learned during your research, who would you say should exercise? And who, if anyone, should not exercise?
Bill: This comes up a lot, because I often get people in the audience of one of my talks who raise their hand and admit they really hate to exercise. They ask me, “What is a form of exercise that I might enjoy?” And my advice is to exercise for how it makes you feel now, how it makes you feel in the moment, whatever that is. Because, while it is true and it’s been scientifically proven that exercise extends lifespan and can help prevent all kinds of health problems, especially cardiovascular problems, it’s no guarantee that you’re going to live a long life. You could be in great shape, you could be a marathon runner, and drop dead at forty-two.
So I always say to people, find a form of exercise that you enjoy, that makes you feel good now, in the moment. That doesn’t have to be in a gym. It doesn’t have to be running on the streets. It could be playing with your kids in the backyard or playing with your dog or dancing alone in your apartment for fifteen minutes. I think the word exercise sort of has a bad reputation, understandably. So I encourage people to think of exercise as synonymous with the word movement. It’s really just about moving your body, getting your heart rate up, getting a sweat going.
I also think the body—it might sound strange the way I say it, but I really feel this way—the body wants to move. There’s a great phrase from Ivan Pavlov, the Russian scientist, where he talked about the feeling of “muscular gladness.” That there’s a feeling of muscular gladness when you are using your body and maybe pushing it a little. It doesn’t mean you have to be a bodybuilder. But take a vigorous walk or play in the park with your dog. It’s just about getting the body moving.
Greg: What did you discover during your research that most surprised you?
Bill: Lots of things. It was quite a fun journey, I have to tell you. My mind immediately goes to antiquity. That’s a period that just fascinates me. I was surprised to learn that gymnasia were common in most towns in the Greek and Roman Empire. They were actual buildings, and they had gym managers that had titles and they had towel boys who had titles.
But more surprising was the fact that ancient Greeks considered the sweat of athletes a prized commodity. So much so that they developed a special instrument called the strigil, which was sort of shaped like a celery stalk and made of bronze or another metal. Athletes would scrape the sweat and oil from their bodies (because they also oiled up before competing) and funnel it into small clay pots. This funky mixture (because I’m sure it’s funky smelling) was called gloios, and it was sold in gyms for medicinal purposes. And the better the athlete or the more famous the athlete, the more expensive was this medicinal potion. So that surprised me because so many people today don’t want to sweat, feel disgusted by sweat and can’t imagine it having that kind of purpose.
Speaking of sweat, sweat has such an important function in keeping us alive. The true physiological purpose of sweating is thermoregulation, to cool the body down if you overheat. So it’s a very sort of ingenious and very simple way to cool the body when it overheats.
But then at the other end of the spectrum, I want to bring this question back to the twentieth century. I didn’t cover every single decade and century in the history of exercise. I just couldn’t do that. But I knew I had to write and wanted to write about Jane Fonda. I grew up in the era when she first came on the scene. I’m sixty-one. And I approached her, with a certain skepticism. I thought it would be sort of campy. But on the contrary, I looked at her early videos and read her early books and read her autobiography and I was really struck by how sensible and how good the workouts were. They would hold up today. The only things that maybe don’t hold up are the gym outfits, the pastels and the leg warmers.
But Jane Fonda was a very gifted teacher, she was great on video, and she truly democratized exercise, especially for women all around the world. Women would “do Jane,” and they could do it at home, didn’t have to get a babysitter, didn’t have to join a gym. They did have to buy a VHS tape, but those were pretty inexpensive. And she continually came out with new routines and new exercise tapes aimed at different audiences, such as menopausal women or postpartum or pregnant. I actually think she is one of the most important figures in the entire history of exercise, male or female. And she was also part of this phenomenon of the fitness industry exploding in the 1970s and 80s and becoming this huge, multibillion-dollar global industry.
Greg: Returning to the ancient Greeks and gloios, what would the people who bought gloios do with it?
Bill: Good question. One would think you would buy gloios in order to become a better athlete yourself, to run faster and lift more. But no. The Greeks used gloios for really ordinary dermatological problems like hemorrhoids and warts. I don’t know how they came up with that exactly. But they believed that gloios contained the essence of arete, or excellence. And somehow that quality could be curative for ordinary dermatological problems.
If anyone’s wondering if this is true, there are examples of strigils in museums like the Met Museum here in New York. I’m sure major museums in many cities would have them too. They’ve been excavated, and you see them on amphorae and vases from that period with athletes scraping off their sweat. It was a real thing.
For a firsthand look at the history of exercise, enter the giveaway for a hardcover copy of Bill Hayes’s book Sweat at the top of this page.