How apt that I reflect on reading Sarah Everts’ The Joy of Sweat as Britain broils in a mini heatwave, my fan whirrs away and I am ever poised to dab droplets from my forehead.

The central paradox that the author unpicks is how so many of us are embarrassed by this natural moisture and its smell, and yet hordes of us pay to break a sweat while in gyms and yoga studios, for example, or chase ‘runner’s high’ as we beat the pavement.

There is even a market for pseudo sweat, catering for anyone from forensic scientists to clothing manufacturers keen to ensure their dyes don’t run thanks to human perspiration.  

In the introduction, medical historian Michael Stolberg also notes how sweat is associated with purification, sexual attraction and masculinity. “That’s a lot of emotional baggage for one bodily fluid to carry,” Everts quips.

The science journalist, who also holds a masters in chemistry, was first drawn to the topic by her own self-consciousness – always being among the first to reach for a towel in a class. But then, having moved to Berlin in the early 2000s, she noticed how much pleasure people took in communal sweat sessions in saunas. Everts often refers to this shared feeling as a catharsis.

As the research begins, it doesn’t take long for her to appreciate that sweat is our “evolutionary superpower”. Part of a highly efficient cooling system that humans have developed over centuries, allowing them to travel far and wide, and to hunt their (often much quicker) prey.

There are between two and five million sweat glands on the average adult human body. No other land mammal comes close in terms of bare surface area – not even our primate cousins, the chimpanzees, who are much hairier and so have to pant to cool down (just like man’s best friend). Meanwhile, cats lick away when they are hot and vultures pee on themselves to evaporate excess heat. As far as potentially awkward cooling methods go (those involving bodily fluids), it could be much worse.

One early revelation is that the nasty whiff many fear to give off – a stigma that dates back to Roman times – is not sweat. “For most of us, a majority of our body odour originates in the apocrine sweat glands found in armpits,” writes Everts. “The other kind, eccrine sweat glands, release the floods of salty fluid when we exercise or are too hot.

“Starting in puberty, apocrine glands begin oozing waxy, fatty molecules into the armpit. Although expelled in microscopic quantities and odourless themselves, the waxy molecules are like candy to the millions of bacteria living in armpits, particularly a genus called Corynebacterium. As the tiny microorganisms devour and metabolise the greasy apocrine molecules, they produce chemical waste. It’s this waste – in effect, bacterial poop – that makes us stink.”

Everts’ investigation takes her from a smell-dating event in Moscow (where participants try to attract an instinctive match by dabbing their sweaty pits with cotton pads that others rank anonymously) to a towel-twirling sauna theatre at the Aufguss World Championships in Finland. In her quest to find the joy of sweat, she has a lot of fun … and so do we.

But the pong of paranoia does linger and I dare you to not feel more conscious of your body odour as you read this book. Why the shame? Well, there are lots of fascinating historical facts to help us understand how we got here. My favourite is young entrepreneur Edna Murphy’s early 19th-century antiperspirant Odorono and how, with the help of J Walker Thompson copywriter James Webb Young, her company put the fear of stink in women (ladies first, of course) and paved the way for an industry worth more than $70 billion.

“His advertisement in a 1919 edition of Ladies’ Home Journal didn’t beat around the bush. ‘Within the Curve of a Woman’s Arm. A frank discussion of a subject too often avoided,’ announced the text below an image of a romantic situation between a man and a woman. ‘A woman’s arm! Poets have sung of its grace; artists have painted its beauty. It should be the daintiest, sweetest thing in the world. And yet, unfortunately, it isn’t, always.”

This one is just plain rude.

In other words, if you want to keep your man then buy Odorono. In the post-Depression era, attention then turned to exploiting the insecurities of men, whose natural scent was once a virtue of their masculinity. This time the message was: if you want to keep your job, use Odorono.

Sweat-related images in the media, and the associations they create in popular culture, are rarely positive. Think of the anxious job interviewee, the emaciated worker, the guilty suspect, the loser about to blow his chance with the girl, the clammy politician lying through his teeth on TV… I mean Jordan Peele #sweatingprofusely is the go-to gif for feeling nervous.

Is it any wonder that the likes of Mikkel Bjerregaard have felt so traumatised by their excessive sweating and their inability to control the most basic of bodily functions? Everts interviews him for the book and he tells her how this affliction has plagued him all the way from high school to the workplace. His desperation is clear to see.

“’I started to feel like this was just how my life was going to be,’” he tells her. “’I really wanted a permanent solution.’ Which is how it came to be that Bjerregaard asked a surgeon to permanently sever the nerve fibres responsible for telling his armpits and hands to sweat [a procedure known as endoscopic thoracic sympathectomy or ETS].”

Everts later laments how this taboo places unbearable pressure on unfortunate people like Bjerregaard. “Regardless of the treatment – if any – that someone with hyperhidrosis decides to seek, I can’t get over feeling that as a society we’ve failed each other and especially people with hyperhidrosis by stigmatising sweat.

“People from Manila to Montreal describe shame associated with sweating too much. How can it be that this fundamental aspect of humanity is so stigmatised that people are moved to take great risks to their bodies to hide, block or eliminate it?”

Another curious and contentious topic is sweat monitoring. The ability to detect extreme fatigue in an elite sportsman so the manager can make a crucial substitution, for example, or to make a timely intervention if a pilot is under significant stress. Perhaps one we can all get behind is the opportunity to  “give a rocket boost in quality of life” for people with diabetes who never want to see another needle or tube. 

It is this ability to be both trivia-tastic and funny, and yet also quietly moving and thought-provoking, that makes Everts a pleasure to read. She is an associate professor yet the language is beyond accessible, eschewing the pitfalls of dry academic text in favour of a “did you know…” approach.

The Joy of Sweat is hardly a call to throw away our spritzes and sprays, and with them our consideration for others, as some people are mistakenly claiming on social media. Rather it is an illuminating re-examination of the body and what it is to be human.

Buy here.