Adults with obesity who lose weight using glucagon-like peptide-1 (GLP-1) receptor agonist medications significantly decreased their physical activity, according to a study presented on June 14 at ENDO 2026, the Endocrine Society's annual meeting in Chicago, Illinois.
The study examined adults taking GLP-1 receptor agonists such as semaglutide, liraglutide, dulaglutide, and tirzepatide. These medications are known to reduce both fat and lean muscle mass. Sajana Maharjan, M.D., of HSHS St. John's Hospital in Springfield, Illinois, said that this makes physical activity essential for preserving strength and long-term health.
Researchers conducted a retrospective pre–post cohort study using data from the National Institutes of Health's All of Us Research Program. This program links participants' electronic health records with Fitbit activity data. Of the 1,950 adults with obesity who started a GLP-1 medication, researchers analyzed 753 people who had sufficient wearable-device data for analysis. The group was predominantly female (78.6%) with an average age of 52.7 years.
The research compared each participant’s physical activity before and after starting treatment by looking at daily step counts and moderate-to-vigorous physical activity minutes. On average, daily steps decreased from 5,047 to 4,487 per day while moderate-to-vigorous physical activity minutes dropped from 28 to 22 per day after beginning a GLP-1 receptor agonist medication.
The largest declines were seen in men and individuals experiencing joint or muscle pain; however, factors such as age, heart failure, or prior stroke did not alter these results. The study also found no evidence that weight loss resulting from these medications led to increased physical activity.
According to the authors, this is the first large-scale study analyzing wearable fitness tracker data among adults taking GLP-1 receptor agonists.
