The science behind the not-so-subtle noises during exertion.
There’s something about a guttural noise that grabs your attention. Whether it’s a harsh sneeze in a movie theater or a snoring stranger on a transcontinental flight, bodily sounds elicit instinctive reactions — surprise, annoyance, humor, disgust.
And then there’s the most gutteral of them all: the grunt.
Spend an afternoon at Equinox, and you’ll hear grunts of all kinds. A fellow member lifting weights to your left, an unusually loud member in Vinyasa Yoga, a hybrid sigh-grunt in the steam room. Maybe you’re the one grunting.
Why We Love to Hate Grunting
Maybe you followed the debate on whether grunting is "cheating" in professional tennis. Why does grunting get under so many people’s skin?
For one thing, it’s been scientifically proven to throw people off of their game, especially in competitive sports. And if you’ve ever been in a Pilates or Barre class with a serial “grunter,” you know that noise can prove incredibly distracting.
But then again, some people need those audible exhales. “As annoying as grunting at the gym can be, it is just not that black and white to be irritated by it,” says Michael Crandall, CSCS, PN2, a Tier X Trainer at E by Equinox - Hudson Yards. “Sometimes grunting is necessary.”
Turns out, there’s more to the science of the grunt than you’d expect. In fact, it may impact your performance.
Why We Grunt
Let’s start with the basics: how a grunt comes up and out.
“The physical element at work here is an increase in intra-abdominal pressure,” Crandall says. “When lifting a heavy load, we draw in a lot of air to prep for the exertion. This air serves us in a mechanical capacity to increase the amount of air pressure in our torso.”
Grunting helps your body in several ways, but most importantly, it stretches your skeletal muscles to increase potential energy and protects your spine, says Crandall.
“When lifting heavy loads, you need a large amount of intra-abdominal pressure to brace and to expand skeletal muscle for force production,” he explains. “Grunting is just an easy way to slowly exhale without full exhalation. A full exhale under heavy load would be very dangerous.”
There’s a psychological reason behind why people grunt, too. One theory, according to researchers at Drexel, is that a grunt signals the body to trigger its fight-or-flight response, thus recruiting more muscle fibers for whatever you’re preparing to lift. In their study, they found that grunting, instead of “regular breathing,” increased handgrip strength by up to 25 percent.
The power of the grunt isn’t limited to weightlifting. There’s one sport that likely comes to mind when you think of grunts: tennis. Turns out, Venus and Serena Williams have been onto something for years. A 2014 study of the sport proved that when tennis players were allowed to grunt, their forehand strokes were stronger in both velocity and force.
How We Grunt
Not all grunts are created equal, according to Crandall. In fact, there are three “styles” that you’ve likely encountered at your local Equinox.
The first is what he calls “unintentional grunting” — the kind you often hear in weight rooms. “Loud, unintentional grunting is probably a good indicator of how hard someone is working,” he explains. “For example, I could deadlift 135 pounds without thinking about it, but if I attempted 350 or so, I might make some unintentional noises to help regulate the air pressure in my torso as well as protect my spine.”
There’s also a distinct difference between grunting while lifting heavy and grunting in, say, a mat Pilates class, adds Crandall. Those sounds likely boil down to a struggle with either flexibility or appropriate breathing — or a combination of both.
“The grunting can signal that what they are attempting is hard for them,” he says. “If you take someone who isn’t that flexible, and they don’t understand respiration and try to put themself in a challenging pose, they are now trying to work into a movement while also signaling to their body to remain rigid.”
In this case, Crandall says the person might need training to shift their “grunt” to a more beneficial sound, such as the yogic exhale. “That ‘sigh’ you hear [in yoga or other classes] is likely a more experienced mover who understands how their body creates new movement or flexibility,” he says. “People sigh or constrict their larynx to more calmly regulate air pressure and create quality breaths and movement.”
And then there’s a third reason: improper breathing. “Sometimes, people just haven’t had the proper education around respiration,” says Crandall. It’s a common issue, which is why Crandall often starts his training programs with breathwork education.
Should You Try Grunting?
In 2018, a study found that even quieter sports and techniques could benefit from a grunt or two. Researchers asked martial artists, who rarely make noise when kicking, to grunt with each kick. The results were impressive. Participants who grunted kicked with about 10 percent more force.
The study suggests that adding a grunt to any burst of movement or fitness could help improve results. So, should everyone try grunting during their workouts?
“It’s a complicated thing but certainly very central to health and improving our fitness routines,” says Crandall. “I don’t know if I would tell more people to grunt without being able to have a larger conversation about why. I would say a better thing to learn is [how] to nasal breathe during exercise and only mouth breathe when the effort requires us to do so.” While there’s still much research to be done into grunting, nasal breathing has been found to improve exercise tolerance by allowing you to breath at a higher aerobic intensity than “normal breathing” through the mouth.
So, focus on your breath, and (maybe) the grunts will follow.