"I’ve become like the person at the train station saying, ‘Have you heard the word of God recently?’ Except I’m like, ‘Have you thought of strength training recently?’" she says.

The 34-year-old from Severna Park, Maryland, got serious about weightlifting in 2024, around the exact time her physician prescribed the GLP-1 medication Zepbound to support her weight-loss journey.

"I wanted to sustain this weight loss long term, and I wanted to manage metabolic illnesses like type 2 diabetes, high cholesterol, and high blood pressure that I was genetically predisposed to, and the answer to that was really building muscle," she explains.

Mendoza is far from alone. Across the United States, a growing number of individuals are making a beeline for the weight room shortly after starting a GLP-1 medication, a shift that is visibly impacting fitness centers nationwide. Between 2024 and 2025, the use of free-weight equipment saw a marked increase in U.S. gyms. According to a forthcoming report from the Health & Fitness Association, a prominent fitness-industry trade organization, gym members are now 6.7% more likely to use dumbbells, 3.8% more likely to use barbells, and 3.6% more likely to use kettlebells. Compared to 2021—the milestone year that Wegovy received approval from the U.S. Food and Drug Administration—overall dumbbell utilization has surged by an impressive 28%.

"Available data suggest that the growing interest in strength training is part of a structural, long-term trend, which in part is accelerated by GLP-1s’ increasing popularity," notes Anton Severin, vice president of research at the Health & Fitness Association.

Of course, weight-loss medications are not the sole catalyst at play. Broader cultural trends emphasizing longevity and functional strength were already nudging more people toward resistance training, Severin points out. However, the rapid ascent of GLP-1 medications introduced an element of clinical urgency. These revolutionary drugs are clinically associated with a reduction in lean muscle mass, making targeted strength training an essential tool to mitigate that loss and protect overall physical health.

Why Strength Training is Nonnegotiable on a GLP-1

To understand the physiological mechanics, any form of rapid or significant weight loss—whether achieved through strict dietary changes, bariatric surgery, or advanced pharmaceutical intervention—invariably leads to some degree of muscle mass reduction, explains Dr. Jyotsna Ghosh, an obesity medicine physician at Johns Hopkins Medicine.

"The most protective things we can do to prevent a higher percentage of muscle-mass reduction are eating enough protein and resistance training consistently," Dr. Ghosh says.

This preservation of muscle is vital because overall muscle mass is deeply intertwined with metabolic health and longevity, becoming increasingly critical as individuals age. Consequently, Dr. Ghosh advises her patients to incorporate resistance training into their weekly routines at least twice a week, aligning closely with the physical activity guidelines established by the Centers for Disease Control and Prevention, which also recommend 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity cardiovascular exercise weekly.

While resistance training can certainly be performed at home using adjustable dumbbells and elastic resistance bands, many of Dr. Ghosh’s patients, much like Mendoza, choose to join commercial fitness facilities. To ensure she continues seeing consistent physiological results, Mendoza lifts heavy weights and structures her training regimen around progressive overload, an exercise philosophy centered on gradually increasing the weight, frequency, or number of repetitions in one’s routine to continuously challenge the muscles. Because these specialized workouts require dedicated equipment, Mendoza initially joined Planet Fitness before eventually transitioning to the YMCA.

How Medicine and Science Shape Exercise Recommendations

The intersection of modern pharmacology and physical culture is far from unprecedented. Throughout modern history, the medical establishment has repeatedly redirected public fitness habits and cultural norms.

"The fields of health and medicine are always shaping how we are recommended to exercise and how we actually do exercise," explains Natalia Mehlman Petrzela, a history professor at The New School and author of Fit Nation: The Gains and Pains of America’s Exercise Obsession.

Major scientific breakthroughs have historically triggered massive cultural shifts in how the public approaches physical fitness. For instance, the landmark scientific discoveries in the late 1960s demonstrating that cardiovascular exercise significantly benefits heart health without dangerous cardiac risks fundamentally transformed public behavior. That revelation sparked a massive cardio boom over the subsequent decades, with high-energy dance aerobics capturing widespread popularity, particularly among women, throughout the 1970s and 1980s.

Eventually, the pendulum swung toward resistance training during the 1990s and 2000s, as mounting medical research suggested that lifting weights could drastically improve bone density and help prevent osteoporosis. Now, more than twenty years later, the mainstream adoption of GLP-1 receptor agonists for chronic weight management appears to be driving yet another profound evolution in how Americans approach physical conditioning.

How Gyms Are Adapting

Fitness operators across the country are actively responding to these shifting consumer behaviors. According to Petrzela, many gyms are physically clearing out underutilized traditional cardio machines to make room for expanded free-weight areas and heavy-duty rack systems. Severin notes that empirical data showing declining usage of standard cardio equipment has led many facility operators to rethink spatial allocation altogether, placing a renewed emphasis on robust strength-training infrastructure. Concurrently, metrics for personal training and small-group training are on the rise, with individual personal training sessions surging by 22% between 2024 and 2025.

Forward-thinking fitness centers are also investing heavily in educating trainers and staff members on the specific physiological needs of clients utilizing GLP-1 medications, developing specialized coaching frameworks tailored to this demographic. This proactive methodology is mirrored at Body Space Fitness, a semiprivate personal training facility in New York City where Kelvin Gary serves as CEO and head coach. To better accommodate a growing clientele of GLP-1 users, Gary ensures his coaching staff receives formal education regarding these medications, which he views as a valuable component of a comprehensive weight-loss strategy when paired with proper resistance training.

"The key for us is helping [these clients] maintain lean muscle mass," Gary says. "Our point is making sure that everyone has a sound understanding of the importance of maintaining their lean muscle mass, and when you’re not eating as much that might mean we need to modify your workout a little bit."

Gary notes that reducing exercise intensity can sometimes be necessary, particularly because GLP-1 medications frequently present side effects such as nausea that can directly impact an individual’s energy levels and workout capacity.

Larger fitness enterprises are scaling similar adaptations. Two years ago, luxury health club brand Equinox introduced a research-backed GLP-1 protocol designed specifically to guide its personal trainers when working with members using the medications. Other nationwide fitness brands have ventured even further into the clinical space. In 2023, Life Time launched Miora, a specialized longevity and performance clinic spinoff offering integrated medical guidance, personal training, recovery therapies, and access to GLP-1 prescriptions. Even lower-cost commercial chains are entering the ecosystem; Planet Fitness announced a strategic partnership with Ro, a telehealth provider specializing in the distribution of GLP-1 injections and oral medications.

GLP-1s Allow Exercise to Have New Meaning

Historically, physical activity has been heavily marketed and perceived primarily as a tool for weight loss. However, with millions of individuals now relying on pharmacological interventions to manage their weight, a profound cultural shift is underway regarding the intrinsic purpose of exercise.

"If people are using GLP-1s as their primary strategy to lose weight, fitness is going to be for accomplishing all sorts of other things, whether that’s building muscle, finding community, or cultivating discipline and newer healthy habits," Petrzela observes.

Dr. Ghosh observes this philosophical transformation firsthand within her own clinical practice. "One cultural shift that I see is that women are more excited to be strong," she notes, adding that outdated stereotypes regarding women avoiding heavy weights out of fear of becoming "bulky" have largely faded into obsolescence.

For Mendoza, allowing a GLP-1 to serve as her primary weight-loss mechanism provided the cognitive bandwidth to reimagine her relationship with physical fitness. "Zepbound helped me clear away space in my brain to actually focus on the evidence-based journey for strength training," she reflects.

Although patients may eventually transition off the medication, many—including Mendoza—have no intention of abandoning their newfound strength routines. Gary expresses optimism that this will become the standard trajectory for individuals who discover weightlifting through their medical weight-loss journeys.

"There is the longevity part of strength training that I think people are going to realize, ‘Yes, we do feel better. We’re at a lower risk for injury,’" he says.

Mendoza wholeheartedly agrees with that sentiment. "If we want to live independently in our old age, especially women, building muscle is so important," she says. "It has really become a huge part of my life."