GLP-1 Drugs and Exercise: A Complex Relationship

GLP-1 medications, such as semaglutide—which is found in Ozempic and Wegovy—have truly transformed weight loss treatments for the better. However, recent research indicates that individuals on these drugs may feel less motivated to maintain other healthy habits.

A team of doctors from HSHS Saint John’s Hospital in Illinois looked into Fitbit data from people dealing with obesity who were prescribed GLP-1 medications. They discovered that, after starting treatment, patients’ physical activity significantly decreased. Although it’s still early days for this study, the researchers suggest that promoting exercise could be vital in the overall care of patients on these drugs.

The GLP-1 Paradox

Exercise might not be the biggest factor for weight loss for many people, but it has traditionally been recommended alongside dietary changes. When individuals lose weight, they typically shed both fat and lean mass—muscle included. Engaging in exercise can help prevent this muscle loss, which is essential for maintaining physical strength and overall functionality.

Even though lifestyle changes can lead to weight loss on their own, GLP-1 treatments have been shown to be much more effective, on average. The researchers aimed to gauge how these medications might change exercise patterns, so they utilized data from the All of Us research program, which monitors the health of a diverse group of Americans.

They concentrated on a selection of 753 volunteers who were prescribed a GLP-1 for obesity and had available Fitbit activity data from before and after their prescriptions. The medications included newer options like semaglutide and tirzepatide, alongside older variants like liraglutide and dulaglutide.

The findings revealed that physical activity among GLP-1 users declined after starting their medication. For instance, the average daily steps dropped from 5,047 to 4,487, and moderate-to-vigorous activity time decreased from 28 minutes to 22 minutes. Notably, men and individuals reporting musculoskeletal pain experienced a sharper decline in their exercise levels.

Next Steps

The team plans to present their research at ENDO 2026, the annual meeting of the Endocrine Society. As such, the findings should be interpreted with caution, given their preliminary nature. Other studies, including findings from substantial clinical trials, suggest that muscle loss might not be a significant issue for GLP-1 users, and many report improvements in physical functioning while on these drugs.

That said, some users, particularly older adults, could be more vulnerable to muscle loss. It’s important to consider that exercise remains one of the healthiest actions a person can take, regardless of their weight or medication. It’s concerning if many GLP-1 users are scaling back their gym or walking habits. The researchers emphasize the need to remind patients about the significance of keeping up with exercise.

“These findings suggest that weight loss alone may not promote increased physical activity, highlighting the need for targeted interventions that encourage physical activity alongside pharmacologic therapy,” they concluded in their paper.