The natural hot springs of Japan’s Kusatsu Onsen. Courtesy of Getty Images. Sweating is often considered a nuisance, one that necessitates frequent mopping of brows or the rethinking of fashion choices on a steamy day. Yet, physiologically speaking, says Dr. Patricia Christie, a lecturer in chemistry and biology at the Massachusetts Institute of Technology, it’s a thing of beauty. Sweating naturally occurs when the body’s core temperature exceeds a certain threshold (typically between 99 and 100 degrees), at which point the brain receives a signal that triggers the release of perspiration onto the skin. There, the beads of moisture — composed mostly of water, salt, potassium and trace minerals — evaporate, removing heat from the body and cooling it down, says Christie.
The process of thermoregulation is a finely tuned adaptation that allowed early humans to chase down fast-moving prey without collapsing from heat exhaustion after a few minutes. Today, it’s the reason we can survive, for example, a gruelling workout class, says Dr. Christopher Minson, a professor of human physiology at the University of Oregon. Sweating, he explains, is part of a cascade of events that increase circulation, repair damaged muscle tissue, lower blood pressure, reduce inflammation, moisturise the skin, fend off harmful bacteria and possibly even boost immunity. “Our ability to sweat and tolerate high temperatures really shaped human evolution,” he says.
In fact, sweating is considered sacred in many cultures. Since the ninth millennium B.C. in parts of Mexico and Central America, people have gathered inside temazcals, enclosed huts heated to blazingly high temperatures with volcanic rocks, as part of a healing ceremony that might also involve drumming and chanting and typically lasts for hours. (The experience is similar to a fever dream, some say.) The ritual is meant to symbolise rebirth and encourage the release of negative energy. In the Middle East and northern Africa, bathing in the steam of a hammam is a form of religious purification, one often practiced before prayer. In Finland and Russia, the custom of visiting the sauna is as much about sweating in 180-degree heat as it is about socialising — both of which deliver health benefits, says Minson. And in Japan, onsens, the thermal springs found throughout the country, can easily reach 122 degrees and serve as a sort of natural hot tub, restoring the body and mind.
Such sweat-inducing rituals haven’t lost their appeal, says Juhi Singh, the founder of the Juhi Ash Center, a holistic wellness space in Manhattan that will soon reopen in a new space equipped with an aromatherapy steam shower and a sauna that uses far-infrared light waves to warm the body. Both options put a modern spin on the traditional Ayurvedic therapies that Singh grew up with in India, and that “combine heat and steam to balance the system,” she says. “Sweating is a key component of good health and helping the body heal and repair internally,” she adds. “I don’t think people realise how important it is.” For those that do, there are also ways to encourage perspiration at home, such as Higher Dose’s Infrared Sauna Blanket V3, which revs up your temperature with electromagnetic field energy and can be enjoyed while you’re on the couch in a state of repose.
The part of sweating that’s less cherished, of course, is the ensuing scent. Pure perspiration, when it’s first released from your pores, is sterile and odorless; it’s the reaction of sweat mixing with the bacteria on your skin that can cause a pungent aroma, says the New York dermatologist Dr. Rachel Nazarian. Antiperspirants can minimise the issue by blocking the pores with aluminium salts. But concerns about the safety of these formulas have inspired some to seek out alternatives, including natural, aluminium-free versions that neutralise smells rather than inhibiting sweat.
The latest plant-based options are both more soothing and stylish than the crumbly, messy natural solids of the past, which often absorbed moisture using baking soda — an alkaline ingredient that tends to dry out and irritate delicate underarm skin, says Dr. Nazarian. Corpus’s botanical range pairs calming vegan glycerin with deodorising minerals, degreasing tapioca starch and refreshing scents derived from neroli, geranium leaf and cardamom. Iyoba’s Probiotic Deodorants hydrate skin and rebalance the microflora of the armpit, allowing healthy bacteria to flourish in order to prevent the bad-smelling kind from taking over — a concept that Dr. Nazarian finds “intriguing and very promising.” Other solids, such as Beautycounter’s the Clean Deo ($28) and Dove Beauty’s 0% Aluminum deodorants ($15 each), come in waste-free, refillable containers and glide on easily thanks to softening emollients.
The downside of sticks is that in high heat — think oven-like 90-degree days — the residue can feel tacky or too slick. But there are other, ultralightweight solutions that sink in like the essences and toners of one’s skin-care routine. Kosas’s Chemistry Deodorant, for instance, has a serum-like consistency and contains alpha hydroxy acids that fight odours, says Dr. Nazarian. Náu’s Floral Cream Deodorant is a remarkably nongreasy concoction made with sweat-wicking rice bran oil and clary sage. Additionally, certain old-school solutions still do the trick: Dr. Hauschka’s talc-free Silk Body Powder, first released in 1968, has rice starch, ground silk and plant extracts to mop up moisture, and Weleda’s classic 12H Sage Deodorant dispenses an antibacterial blend of sage, rosemary and lavender in a nonsticky, aerosol-free mist.
Or, you might decide to go au naturale and simply wash your underarms with a gentle bacteria-ridding soap that leaves behind a light fragrance, such as Binu Binu’s Shaman Charcoal Soap ($20), made with lavender and purifying charcoal. Just be aware that, whether you switch to a natural deodorant or to wearing nothing at all, giving up antiperspirant often involves an adjustment period, during which time the acid mantle — the thin acidic layer on the surface of skin — rebalances itself. “It takes a couple of weeks for the buildup of antiperspirants to completely dissipate from your skin,” says Dr. Nazarian. “This causes a flourishing of bacteria, which can change the way you smell until you shift back to your baseline or ‘normal’ mix of flora.”
It can feel like you’re sweating more during this so-called detox period but, in fact, your perspiration rate is the same, it’s just that using antiperspirants lessens the effect. And if this should create a slightly stronger aroma, is that so bad? After all, scent is highly subjective. In 2012, the Brooklyn-based artist Martynka Wawrzyniak bottled the essence of her own sweat, tears and hair as part of a solo exhibition, “Smell Me,” and later received requests to sell the resulting eaux. Minson would prefer that we embrace the wonders of thermoregulation and not stem the flow of sweat entirely. “As humans, we are becoming thermostatic — we don’t like to feel hot or cold, we don’t like to sweat, we prefer to go from perfectly air-conditioned houses to our cars to work,” he says. “But challenges that either raise or drop our temperature provide good forms of stress, recovery and adaptation.” When the next heat wave hits, who knows, you might find yourself throwing open the windows.
