Ozempic: Muscle Loss & Weight Loss Risks
New Weight-Loss Drugs May Impact Long-Term Health, Researchers Warn
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University of Virginia researchers are urging caution and further study on the long-term effects of GLP-1 drugs on cardiorespiratory fitness, a key indicator of overall health and longevity.
Siddhartha S. angadi, PhD, Associate Professor of Kinesiology at UVA’s School of Education and Human Progress, and his colleagues have reviewed available data on the effects of GLP-1 drugs, a popular class of medications used for weight loss and diabetes management, on cardiorespiratory fitness (CRF). Their findings raise concerns about potential long-term consequences for patients.
Understanding Cardiorespiratory Fitness (CRF)
CRF, often measured as VO₂max, is a critical metric that quantifies how efficiently the body utilizes oxygen during physical activity. It serves as a valuable tool for healthcare professionals to assess the integrated function of the heart, lungs, muscles, and blood vessels. Crucially, CRF is a powerful predictor of all-cause and cardiovascular mortality.
Patients with obesity frequently exhibit lower CRF. This can be attributed to insufficient muscle mass or compromised muscle quality due to fat infiltration.
“cardiorespiratory fitness is a potent predictor of all-cause and cardiovascular mortality risk across a range of populations, including obesity, diabetes and heart failure,” explained Angadi, a cardiovascular exercise physiologist with UVA’s Department of Kinesiology. “In a recent study by our group that examined mortality outcomes from almost 400,000 individuals across the world, we found that CRF was far superior to overweight or obesity status for predicting the risk of death. In fact, once CRF was factored in, body weight failed to predict the risk of mortality. This is why it’s so vital to understand the effects of this new class of drugs on it.”
GLP-1 Drugs and CRF: A Mixed Picture
The researchers’ review of existing medical literature revealed that while GLP-1 drugs demonstrate improvements in certain aspects of heart function, these benefits do not appear to translate into important enhancements in VO₂max.
While some smaller studies have suggested that exercise might help improve VO₂max in patients taking GLP-1 drugs, the researchers note that these studies had limitations in their controls. Larger, well-designed studies are needed to confirm these potential benefits.
Ensuring Healthy Weight Loss
The researchers’ ultimate conclusion is that GLP-1 drugs “substantially reduce body weight and adiposity, along with a substantial FFM [fat-free mass] loss, but with no clear evidence of CRF enhancement.” This lack of CRF advancement raises concerns about the potential impact on patients’ metabolic health, healthspan, frailty, and overall longevity.They emphasize the need for additional research to fully understand the drugs’ effects and to ensure optimal patient outcomes.
Promising Avenues for Future Research
Despite these concerns, there are promising signs that future interventions could mitigate these effects. The researchers highlight a monoclonal antibody currently in development that might potentially be able to counteract lean muscle loss.
“This is an area of active research, and we are hopeful that better solutions are coming soon,” said Liu. “But for now it is important that patients prescribed GLP-1 drugs have conversations with their healthcare providers about strategies to preserve muscle mass. The American Diabetes Association recommends screening for malnutrition and low muscle mass risk before starting these medications and promoting adequate protein intake and regular exercise throughout treatment.”
Angadi added, “Exercise training during GLP1 therapy remains to be assessed in its ability to preserve or improve VO₂max during GLP1 therapy.”
Findings Published
The researchers have published their findings in the Journal of clinical Endocrinology & Metabolism. This work was supported by the National Institutes of Health, grants R01DK124344 and R01DK125330.