TikTok is where fitness trends come to thrive — from the "12-3-30" workout that features a treadmill routine for weight loss, to the "ab dance," a standing abdominal move that involves crunching your abs while swinging the arms.
Another move that has gained popularity among social media users: an isometric abdominal exercise called the "stomach vacuum."
If you search the hashtag #stomachvacuum on TikTok, you'll see a stream of dramatic snapshots from the move, particularly the drastic inhalation, sucking in the stomach and exposing the lower ribs.
Jenny Brennecke, a physical therapist and online coach, started her TikTok account @drjennypt about two years ago, posting mostly humorous and motivational fitness-related videos with some exercise tutorials sprinkled in. One of the moves she broke down for her audience? The "stomach vacuum."
How to perform the 'stomach vacuum' exercise
On April 17, Brennecke shared a "stomach vacuum" tutorial guiding followers through a visual demo, which has racked up more than 210k views. She recommends performing this exercise first thing in the morning on an empty stomach.
Start by exhaling all of the air out of your lungs.
Drive your belly button back toward your spine. Brennecke uses the analogy of walking into a cold lake or pool in order to contract the abdominal muscles.
Hold your breath for 10 to 15 seconds, then release.
Repeat for five sets; three-four times a week.
What does the 'stomach vacuum' exercise do for the body?
At its core (pun intended), the "stomach vacuum" is a strengthening move that targets the front abdominal muscles, especially the transverse abdominal, through an isometric hold.
Dr. Jordan D Metzl, a Sports Medicine Physician at Hospital for Special Surgery and author of “The Workout Prescription,” calls the move “a biceps curl for your abs” and compares the exercise to a plank.
Katie Wang, personal trainer and founding trainer at Barry’s X, likens it to “doing an isometric squat hold, just for your core, like a hollow body hold. When you’re doing a hollow body hold, you’re practicing a (different version) of that 'stomach vacuum.'"
While the stomach vacuum has caught fire on social media more recently, Wang told TODAY that the move is nothing new to the fitness space. “They’ve been around for forever,” Wang said, explaining that most people have likely done the move during a workout without even realizing it.
“I promise you, your yoga instructors have talked about it, your Pilates instructors have talked about it ... any time we’re saying, ‘belly button to the spine,’ it’s a version of that stomach vacuum,” Wang explained.
Brennecke’s TikTok tutorials may be recent, but she first learned about the isometric abs exercise when she pursued her doctorate in physical therapy, where they refer to the move as “hollowing” or “bracing.” Brennecke says that she teaches the "stomach vacuum" to her clients to help them to connect on a deeper level with their body, in addition to reaping other rehabilitative benefits.
"This is a technique used in physical therapy, so it is safe, it is effective, and it does have a lot of research to support it," Brennecke said in her video. "So it can also help reduce your low-back injury risk, it can control the postural control and stability within your spine and your pelvis, as well as to be able to control and strengthen your abdominals on command."
For Wang, she sees the "stomach vacuum" as a way to connect deeper with your body, too, specifically with your breath and how it can help abdominal muscles contract.
“There is this level of fitness that you can unlock when you start to mentally connect with your body during a workout and during your breath. So I think therein lies the beauty of the technique," Wang explained. "It's breathwork, it's isometric contraction, muscle connection. And as the sculpting and the toning comes, or the shifting of your body composition comes toward the end, that's great. But I think the (benefits) to highlight are more so a strength that can come from it, and a deeper connection and contraction."
Is the 'stomach vacuum' exercise safe?
All three experts agreed that there is no major risk in doing the isometric strength move. However, if you have high blood pressure, Wang and Brennecke both cautioned against doing the "stomach vacuum" as it can cause an increase in blood pressure.
If you're trying this move for the first time, don’t push your limits of how long you can hold your breath. While Wang said that calling the move “dangerous” is “dramatic,” she suggested building up tolerance before performing a lengthier "stomach vacuum" versus jumping right in with more than your body is used to.
“Holding your breath … always comes with downsides. That’s why people (who) preach 'stomach vacuuming' often suggest starting with shorter periods of time. But if you start to feel lightheaded, you don’t want to be doing them,” she cautioned.
Brennecke recommends starting with a smaller increment, such as 10 seconds, and working your way up to 30 seconds over time.
The "stomach vacuum" is versatile in that it can be done from multiple positions: standing up, lying down, leaning on a surface, in a chair. But when it comes to beginners, Wang suggested starting on the ground and getting more advanced from there. That way, you're already lying on the ground in case you do get lightheaded from not being used to the breathwork.
The downside of the "stomach vacuum" exercise
The biggest risk is one you can’t see: the misinformation and visuals on TikTok that can take a toll on your mental health.
Some TikTokers demonstrating the "stomach vacuum" claim it results in a slimmer waistline and a flatter stomach — but all three experts TODAY spoke with confirmed that this is highly exaggerated.
“You’re not going to master 'stomach vacuums' and all of a sudden have the flat stomach, if you’re not also looking at your diet and everything else you’re doing as well,” Wang explained, calling the ideology behind that “dangerous.”
And it’s not just misinformation that can be harmful: The visuals after searching “stomach vacuum” on TikTok can be problematic for those who have body image issues or have battled eating disorders. TikTok has noticed this, too. Searching for “#stomachvacuum” on the platform triggers a resources page for the National Eating Disorder Association.
Wang said that if you go into doing the "stomach vacuum" with the mindset of wanting to “save inches” off your waist, practicing the move can become “less healthy.”
“With any trends in fitness, it can always be a little risky, and with any trends in general on the internet, it comes with the caveat of, it works for some people and it doesn’t work for others,” Wang said.
But as long as you approach the exercise with a healthy mindset, Wang said that there are benefits to be reaped — from helping with posture to strengthening core muscles to deepening the connection with your breath.
How to incorporate the 'stomach vacuum' into your routine
When it comes to who can reap the benefits of the "stomach vacuum," the answer is everyone.
The one caveat Metzl has with the "stomach vacuum" is that it primarily focuses on strengthening the front muscles of the core, making it a disproportionate move to the back muscles. There's no harm in that, Metzl said, but he explained that if you're primarily interested in strengthening your core muscles, you might want to look for a move that tackles both the front and the back.
"If you’re a bodybuilder, and you just want to look good up on the stage with ripped abs, that’s fine," Metzl said. "But if you actually want a back (for) playing golf and with your kids, and you know, doing a triathlon and playing baseball, I’m much more a fan of strengthening the muscles in the front and the back of the spine at the same time."
An alternative move that does? The plank. "Planks ... they really work; I would come down strongly in favor of planks. Because it strengthens both the front and the back. It's a similarly isometric exercise, meaning it doesn't get longer or shorter, and so I'm a big fan of that," Metzl said.
If you are already actively working out, Wang suggested incorporating the "stomach vacuum" into a program that you’re already doing, paying attention to engaging your core throughout and controlling your breath to deepen that connection.
All of this is to say, the "stomach vacuum" — trend or not — can be an effective fitness tool when used in the right way and for the right purposes.
"When you see a trend on TikTok, whatever it is, whether it's 'stomach vacuums,' or slugging or your next beauty viral thing, do your research, keep looking, stay curious, hear more opinions and narratives and experiences. And then see how it fits in within your lifestyle," Wang said.