During a Harry Styles concert at the Forum in Inglewood, Calif., last month, Shealee Governatori suddenly found herself short of breath. The culprit wasn’t excitement. It was the tightfitting waist trainer she was wearing under her clothes.
After being squeezed into the corset-like contraption for “like eight hours,” the 20-year-old, who works in social media, tweeted: “I’m breathing like it’s 1600s England.” She wasn’t sure she’d ever put it on again. Yet she returned to wearing it for quick walks and workouts, vowing to never “wear it so long on a normal day,” she said.
Women lately are getting bent out of shape by a product designed to give them a new shape—or a very old one. Waist trainers—latex undergarments that wrap tightly around the belly and cinch in the waist for an hourglass figure—came into vogue around 2015, when Kim Kardashian West and her sisters began praising them on Instagram.
The item, which mimics the look and shape of an old-time corset, is the latest front in the battle between comfort and fashion; women’s reactions vary by generation, their feelings about beauty standards—and whether they don’t mind forgoing eating or breathing.
Unlike a girdle or a pair of Spanx, which are worn for temporary smoothness, these trainers are often touted as weight-loss aids that will trim and shape the waist if worn throughout the day or while exercising. Fitness experts have doubts about any lasting benefits, however, and some wearers are calling them torture.
“My insides felt crushed from the moment I put it on,” said Kate Proud, a small-business owner in Ballarat, Australia, who wore one to a wedding earlier this year. She had enlisted her husband and a friend to help get her into the waist trainer, but once she got to the event she decided to take it off. After 20 minutes, it made her “very hot” and “like my internal organs were being squashed together,” she said.
Ms. Proud recently posted a picture of herself on Instagram struggling to fit into a waist trainer, alongside a picture of Ms. Kardashian West wearing one seemingly effortlessly. “I decided to bring awareness to all women that being a real woman is OK,” Ms. Proud said.
Ms. Kardashian West didn’t immediately respond to a request for comment.
Stephanie Rodriguez found wearing a waist trainer tough at first, with “broken fingernails, grunting, laying on bed to put on,” but now “it’s like a second skin.” The 34-year-old administrative assistant in Chicago said she wears hers every day. After some doubts, she believes it is helping her reduce stomach fat, but she’s realistic. “Diet and exercise will help a lot, not just a waist trainer.”
Sari Alvarez of Fort Lauderdale, Fla., called her attempt to wear a waist trainer for a day last year the “worst decision ever.”
“As soon as I took it off, my back was in such tremendous amounts of pain. I could not sleep properly for a few days,” she said. The 28-year-old legal assistant tried using it just while exercising, but even that felt uncomfortable.
“I understand losing belly fat is the hardest part of working out, but I would not go through those lengths to achieve that goal,” she said.
Fitness trainer Tracy Anderson warned against using them on her website. The post notes that women who wear them can find eating uncomfortable because their abdomens are so squeezed.
“I would argue these devices should be called waist de-trainers because that is what they are actually doing,” said Steve Ball, professor of exercise physiology at the University of Missouri. If worn over long periods, the constant external support can lead the core ab muscles to become weak. “In fitness, there is no quick fix,” he says.
Waist trainer manufacturers such as Waist Gang Society, Waist Shaperz and Angel Curves have called those claims overblown and unproven. Some companies post disclaimers on their websites, saying results will vary from person to person or encouraging diet and exercise for the best results.
Ruben Soto, president of Hourglass Angel, a Riverside, Ill., company that has been making waist trainers since 2007, says the benefits of wearing one include “a slimmer-looking waist, which can be a confidence booster,” improved posture “for a more confident look,” and “the added benefit of feeling fuller faster when eating given that the waist trainer is compressing the midsection.”
Some even say they have “thermogenic action” (or heat-producing) technology that makes the stomach core area sweat while worn. Trainers, which often cost from $70 to $150, are promoted on Instagram, where some brands have hundreds of thousands of followers.
The look, of course, predates social media. Corsets—constricting upper-body undergarments with laces, hooks and eyes in the back—were worn throughout the Western world starting in the 16th century.
Around the time of the French Revolution, corsets fell out of favor as aristocratic styles became frowned upon and ideas of liberation extended to women’s clothing. But they sprang back into fashion by the 1810s. For the next century, “boned corsets were an essential component of women’s fashion,” as Valerie Steele, director of the Museum at the Fashion Institute of Technology in New York, writes in her book “The Corset, a Cultural History.”
Even then, the old-fashioned corset was perceived by some as an “instrument of torture” and a cause of ill health and even death. While tight corsets could be uncomfortable and in some cases cause fainting, there is no evidence that they split a wearer’s ribs or caused tuberculosis, as some claimed, Ms. Steele said in an interview.
The image of Scarlett O’Hara gripping onto a bedpost as Mammy tightly laces her corset in “Gone with the Wind” endures as visual shorthand for the difficulties of wearing one.
The “proper old-school corset” made a comeback with Nathalia Urban, who bought one after liking the way her waist trainer made her look and feel. The 30-year-old translator, who lives in Edinburgh, Scotland, said “it was hard as hell to put on. I ended up tied to my room’s doorknob,” after watching one too many YouTube tutorials on how to lace herself up in one. She finally asked for her partner’s help to squeeze into it.
“It’s still uncomfortable, and I walk like a robot when I’m wearing it,” she said. “But I feel super sexy and powerful when I have my corset on.”
Write to Ray A. Smith at ray.smith@wsj.com