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IF YOUR SOCIAL media feeds are filled with dumbbell curls and hot takes about training tempo, the same algorithm that might have served you this article has also likely been populated with clips of fitfluencers—like this one and this one—sucking their belly in and standing with their stomach flat like a pancake. They’re not just goofing around—they’re performing a stomach vacuum, a classic bodybuilding pose.
Their claims regarding its benefits are exciting for a move that doesn’t require any equipment (other than maybe a mirror): Suck in your stomach to strengthen your deep ab muscles, shrink your waist, and protect your low back. It’s simple enough to do, so you’re probably wondering where this hack has been all this time, and how you can get started.
While the stomach vacuum is an exercise that can benefit some people, it’s also a reemergent trend that is being overstated and overhyped. To separate the legitimate benefits from the internet myth-making, we consulted Dr. Pat Davidson, a PhD in exercise science and a competitive bodybuilder, as well as Ebenezer Samuel, C.S.C.S., Men’s Health fitness director.
What Is the Stomach Vacuum?
“The stomach vacuum is where you suck your gut in by pulling your belly button to your spine,” Davidson explains. The move primarily targets your transversus abdominis (TA)—the deepest layer of your core that wraps around your midsection like an internal weight belt. It stabilizes your spine, supports your pelvis, and regulates the movement of your ribs when you breathe.
The stomach vacuum shows up in several corners of the fitness world. Yogis use it during breathwork practices that emphasize diaphragmatic control. Physical therapists use versions of the maneuver with clients recovering from back pain to promote deep-core activation. Bodybuilders practice it to demonstrate elite abdominal control on stage.
It’s hard to pinpoint who first performed the stomach vacuum, but the technique became iconic thanks to Frank Zane, a three-time winner of bodybuilding’s most prestigious competition, the Mr. Olympia. When Zane stepped on the Olympia stage in the ’70s, he’d throw his hands overhead and pull his stomach so far inward it looked like someone had hollowed out his midsection. The move mesmerized fans and judges, and has since become a standard in competitions for anyone trying to demonstrate serious abdominal control.
What the Science Says
Zane wasn’t using the vacuum as a training exercise, but as a way to present his physique to the judges. But today’s content creators often blur that line, selling the vacuum as a shortcut to a smaller waist when, historically, it was more about showmanship. But if not aesthetics, what is the move’s actual function?
The level of control necessary to achieve the vacuum, Samuel explains, can lead to healthier shoulders and back muscles as well as improved ranges of motion over time.
Most research on the stomach vacuum—usually studied under terms like “abdominal drawing-in” or “abdominal hollowing”—looks at what the movement does to your deep core muscles, not whether it shrinks your waist. Because there are very few studies examining the stomach vacuum on its own, many influencer claims are extrapolations based on general deep-core training benefits. Here’s what the science actually supports so far.
Stomach Vacuums Can Strengthen Your Core
Stomach vacuums reliably activate the transversus abdominis (TA), the deepest abdominal muscle that wraps around your waist like an internal corset. The TA is always working in the background to stabilize your spine during daily movement, but it rarely gets targeted the way your biceps or chest do during traditional strength training. The vacuum gives you a way to directly engage and strengthen this hard-to-reach muscle.
Research (like this small study) on abdominal hollowing show that this pattern can increase TA thickness and engage other deep-core stabilizers (like the internal obliques and multifidus) as effectively as classic core exercises such as bird dogs or curl-ups.
Stomach Vacuums Can Help Ease Back Pain
The stomach vacuum is not a cure for back pain, but its ability to improve deep-core activation has been shown to help some people with chronic low-back discomfort. In one 40-subject study, abdominal drawing-in improved spinal stability without adding load to the spine. In another small four-week trial, participants who focused on activating the TA saw greater reductions in disability scores compared to those doing conventional exercises.
Again, the benefit isn’t from “sucking in.” It’s from teaching your deep core to fire consistently and support your spine during movement.
Stomach Vacuums Will Not Shrink Your Waist
Despite what you see on social media, there’s no scientific evidence that stomach vacuums can reduce waist circumference or body fat. Even ab training on its own merits doesn’t change your waist size unless paired with changes to your body composition.
“I think it’s just anecdotes and opinion that vacuums can shrink your waist,” Davidson adds. “But you can get better at performing the action and holding the position, so you can consciously present a more sucked in stomach look by holding the position.”
So How Do I Shrink My Waist?
The stomach vacuum may give the illusion of a small waist, but, really, there’s only one definitive path toward a tighter midsection: Strength train your abs so they appear larger, and eat in a sustained caloric deficit so your waist circumference drops and your abs become more visible.
The good news is that this is a simple and proven strategy that will work for anyone. The tougher pill to swallow is that this approach requires more planning and consistency, and, depending on your starting physique, may take several months to years to achieve.
Stomach Vacuum vs. Bracing
Both bracing and the stomach vacuum engage your core muscles, but they achieve two very different things. The stomach vacuum selectively activates and strengthens your deepest core muscles; it’s low-load, slow, and focused on control. Bracing, on the other hand, is a technique used during heavy lifts, such as back squats or deadlifts. Instead of pulling the stomach inward, you expand and flex your midsection outward to create rigid trunk stiffness and protect your spine under load.
“Very often when we’re in the gym, we’re bracing, and we’re taught to, you know, stand up tall, squeeze our shoulder blades,” says Samuel. “That’s kind of good posture, but none of that is hitting the notes that we get with a stomach vacuum.”
How to Do the Stomach Vacuum
If you do want to give the stomach vacuum a try, Samuel says you don’t need to train it much. Just two to three sets of five reps or five minutes of total work is enough to help teach you about breathing and expanding your awareness in those target areas. Start with two to three sessions per week. Here’s how to do it:
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First, choose your starting position. You can do it flat on your back, on your hands and knees, or from standing. Try it lying down first.
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Breathe in through your nose and expand your stomach with air so it rises up. Take in as much air as possible.
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Exhale and blow to release all of the air. Take as long as you need to empty your stomach and lungs.
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Once you’ve exhaled all the air you can, suck your belly button up toward your spine so your mid-section looks like it’s been scooped out. Hold this position for 20 to 40 seconds, then breathe in and begin your next repetition. Try for five reps and build from there.
So, are stomach vacuums worth trying? Sure. A few short sessions per week can help you strengthen your deep core muscles, improve your breath control, and—if you’re a bodybuilder—give you a tighter-looking midsection on command.
But you’re not going to get you a major performance boost or transform your physique by sucking in your belly. The stomach vacuum is a tool, not the quick-fix hack that TikTok often makes it out to be.
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