Adults utilizing GLP-1 medications for weight loss are significantly reducing their physical activity, according to a new study that highlights potential risks for muscle mass loss and overall long-term health. The research found that participants using drugs such as Ozempic and Wegovy experienced a notable decrease in daily steps and moderate-to-vigorous physical activity.
The study, presented at the Endocrine Society's annual meeting, analyzed data from 753 individuals with obesity who began a GLP-1 medication. Researchers observed an average daily step count reduction from 5,047 to 4,487. Moderate-to-vigorous physical activity also dropped from 28 minutes to 22 minutes per day. The most significant declines in activity were seen in men and individuals reporting joint or muscle pain.
Sajana Maharjan, M.D., lead author of the study, stated that GLP-1 drugs reduce both fat and lean muscle mass. "The findings in our study reinforce that exercise cannot be optional for people taking these medications," Maharjan said. "People need targeted interventions that encourage physical activity alongside medication for obesity."
Experts caution that weight loss achieved through calorie deficit can sometimes lead to a lower metabolic rate, as the body conserves energy. Additionally, side effects associated with these medications, such as nausea and fatigue, may further diminish a person's inclination or ability to exercise. Without adequate physical activity, a substantial portion of weight lost may be from muscle rather than fat.
Specialists emphasize the importance of incorporating resistance training and regular daily movement, like walking, into the routines of GLP-1 users. This is considered crucial for preserving lean muscle mass, maintaining metabolic health, and supporting sustainable weight management. Exercise also plays a vital role in supporting bone and joint health, as well as enhancing cardiovascular fitness.
However, one contrasting view from board-certified internist Dr. Amanda Kahn suggests that her clinical experience differs. Kahn believes that weight loss often acts as a motivator for patients to become more physically active and engaged in their health. She argues that when GLP-1 medications are prescribed with careful attention to nutrition, resistance training, body composition monitoring, and laboratory testing, patients can achieve weight loss while improving their strength and motivation for exercise.
Kahn stressed that the success of GLP-1 therapy is closely linked to the provider's expertise. If a patient experiences excessive fatigue, nutritional deficiencies, or significant muscle loss while on these medications, she considers it a monitoring issue rather than a problem with the medication itself, underscoring the need for close clinical oversight. She advises that preserving strength, function, and metabolic health is as important as the number on the scale.