By Archie Belfield & Professor Leigh Breen, School of Sport, Exercise and Rehabilitation Sciences at the University of Birmingham on behalf of the ATTAIN Healthy Ageing Network
GLP-1 receptor agonists offer promise for the treatment of obesity and related conditions like Type 2 Diabetes. They include well publicised brand names like Ozempic and Wegovy, that have received well-publicised celebrity endorsements. In the UK and US, off-label prescription of these medicines has surged, and demand far exceeds supply.
This class of medications act to mimic the effects of a hormone which the body produces called GLP-1 to promote weight loss through reducing food intake. This is done by providing the GLP-1 hormone in injectable or tablet form. The widespread use of these medicines comes with considerations for clinicians, exercise professionals and patients. However, while they offer great promise as a treatment in a manner that is comparable to bariatric surgery, these interventions share a common challenge; – unintended skeletal muscle mass loss during the reductions in body weight.
When people with obesity take GLP-1 receptor agonists, substantial weight loss occurs. The downside is that an estimated 25-39% of the weight lost comes from muscle mass. This contribution is similar to that seen with diet-induced weight loss. Without exercise or physical activity intervention, muscle mass loss accounts for 28-35% during diet-induced weight loss.
Considering the importance of skeletal muscle for mobility and functional tasks and the body’s largest organ, with diverse roles in metabolism, maintaining skeletal muscle mass is essential for overall human health.
The potential adverse effects of GLP-1 agonist treatment on muscle strength and function should raise concern for healthcare practitioners and exercise professionals, but more research is required to understand the clinical implications of muscle mass loss with these new diabetes medicines. However, there is clear evidence that concurrent lifestyle intervention, such as the promotion of physical activity, may help to support muscle maintenance in those using weight loss medicines. The preferential loss of fat over muscle mass is undoubtedly conducive to long-term weight loss maintenance (i.e., lowering risk of weight re-gain), with the potential for profound impact on healthcare economies as the incidence of obesity and Type 2 Diabetes continues to rise.
Physical activity and exercise are well established strategies to promote muscle mass and strength maintenance during weight loss. With resistance exercise or combined resistance and aerobic exercise training the contribution of muscle mass loss to overall body weight loss can be dramatically reduced. So, how does this happen? During the ’energy-stress’ that occurs with GLP-1 receptor agonist treatment, the body may prioritise energy towards metabolic processes in fat tissues, which has a negative effect on skeletal muscle metabolism. Exercise and physical activity act directly on skeletal muscle metabolic processes to support the maintenance of muscle mass, strength and function during periods of weight loss.
Whilst these new class of diabetes medicines may appear remarkably effective for weight loss and the treatment of metabolic disease conditions, physically active living and structured exercise interventions are vital to ensure that sustainable healthy weight loss is achieved.
Outside of the clinical setting, community initiatives such as water aerobic activity and musculoskeletal (MSK) health hubs pioneered by ukactive offer a bridge to healthy weight loss in those with obesity and Type 2 Diabetes, especially in deprived and/or ethnically diverse communities, where the prevalence of these conditions is disproportionally high and long-term complications are often more severe.
To find out more about the ATTAIN Research Ageing Network, click here.
To access ‘Guidance for sport and physical activity on understanding the use of Weight Management Medications’ developed by ukactive and CIMSPA, click here.
Disclaimer: Any views or opinions expressed are solely those of the author and do not necessarily represent those of ukactive.
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