GLP-1 and Exercise: What Personal Trainers Need to Know

Personal trainers are likely to work with clients both on and prescribed the medication, and thus, they should understand its effects to modify training programs.  

GLP-1 medications are effective weight-loss drugs that have become well-known and accessible recently (3). They can yield 15–20% weight reductions in adults, previously only possible after bariatric surgery (4). The effects of GLP-1s increase postprandial insulin secretion from pancreatic β-cells, suppress glucagon secretion from α-cells, slow gastric emptying, and reduce appetite (4).

As much of a “miracle weight-loss drug” as the media has made it out to be, it is intended to be used in adjunct to lifestyle interventions to be successful. 

If your clients are taking this drug or used to take it, exercise should be an essential variable to include. In this article, we’ll look at some reasons why exercise, primarily via resistance training, is crucial to lose the most weight while on GLP-1 and reduce weight regain when off of it 

Exercise protects against losing muscle mass

Being in a caloric deficit alone can result in 10-30%, even 40% in some cases, of the weight lost from muscle mass. This is detrimental, as muscle mass is metabolically active and contributes to many physiological processes. Some studies show that GLP-1 use without exercise leads to similar lean muscle mass loss patterns compared to medication-free weight loss (4; 10). 

Yet, other studies show a muscle atrophy-protecting effect (12; 13; 15). However, the studies showing a muscle-loss-protecting effect were done on mice and measured for muscle in ways much different from in humans. Furthermore, the human subject trials varied in length and dose, which makes it hard to conclude GLP-1 use prevents muscle loss while losing fat at this time, and we don’t know if exercise was a variable controlled for.

Why exercise when taking GLP-1s?

If your client is on a GLP-1, wouldn’t you want to do everything possible to leverage its effectiveness and help them lose the most weight while on it? How does exercise influence weight loss outcomes in those who are on GLP-1? One recent randomized control trial split participants into an exercise group, a GLP-1 group, and a combined group (11). 

The results showed that the combined group, which did 150 minutes of cardio a week, lost 6.1% in abdominal fat. The exercise group lost 2.6%, and the GLP-1 group lost 2.8%. When exercise is leveraged with GLP-1, the weight loss effect is more substantial, leading to a lower risk of type 2 diabetes and cardiovascular disease. Interestingly, GLP-1 alone was only marginally better than 150 minutes of cardio per week. 

These results show that even cardio training has a muscle protective effect compared to no exercise at all. Imagine how much better adding additional strength training would be.

Another benefit of exercising while taking GLP-1 is stronger bones or higher bone mineral density. One recent study found that Liraglutide, a GLP-1 medication, lowered bone mineral density, but when it was combined with exercise, bone density was preserved (7).

GLP-1 treatment has been shown to increase resting heart rate (Gross). However, in one study, significant increases in resting heart rate were not observed when exercise was added to GLP-1 use (8).

Most available studies on exercise and GLP-1s used only cardio-based training and didn’t use any out-of-the-ordinary guidelines. Most used the basic “150 minutes per week at moderate intensity” guideline. Future research should investigate the best exercise types while on GLP-1 (9). 

In sum, many studies show that combined exercise and GLP-1 produce the best results, both while on and after discontinued use (1; Lehman, 2021).

Exercise to maintain weight loss after GLP-1 deprescription

In 2025, many insurance providers are changing the rules to narrow the qualifications for being prescribed the drug. This will lead to many people losing access to the medication, and back to square one: weight loss through lifestyle change alone. This is where personal trainers will play a pivotal role. 

One study found that two-thirds of the weight loss was regained after one year off GLP-1 (6). Other studies show that weight regain after GLP-1 use is common (2; 14). Only some people can use GLP-1 for the long term, so what if an established exercise routine during GLP-1 use could result in maintained weight loss? 

A study investigated whether weight loss was sustained better one year after termination of a GLP-1, supervised exercise program, or combined for one year (6).

In the study, participants who received supervised exercise instruction maintained a weight loss of at least 10% of initial body weight one year after treatment termination compared with those who received liraglutide alone or placebo (6). Weight regain during the one-year post-treatment phase was 6 kg larger for participants who had previously received liraglutide alone than participants who had previously received supervised exercise alone, despite similar initial weight loss. 

These results show that adding supervised exercise during GLP-1 use improves weight loss maintenance after treatment termination. Other randomized control trials show similar results, too, with the best results coming from supervised exercise exceeding the 150-minute/week guideline (8; Wilding).

These findings from research can be used by personal trainers to share with their clients, when appropriate, to highlight the importance of exercise, especially strength training, while on and off GLP-1s. 

Exercise can help reduce self-perception of poor health

Taking medication may reinforce the belief of being unhealthy. It has been shown that seeing one’s health as poor is closely related to a higher prevalence of chronic diseases, mortality, depression, and hospital visits (5). This belief can also lead to decreased lifestyle change, triggering a spiraling downward slope.

In the study by Lundgren et al., treatment with both a GLP-1 and a placebo significantly reduced the health perception. On the flip side, adding exercise to the GLP-1 did not substantially change the patients’ general health perception, with exercise groups maintaining their initial improvement in well-being after the first weight-loss maintenance phase. 

Through increased self-efficacy, exercises protect against poor health perception that can accompany the use of GLP-1s.

Conclusion

As more research comes out, it is clear that GLP-1 is a powerful and safe weight-loss medication. It doesn’t seem to be going anywhere, and people are pouring money into it. Though changes in access are on the way that have potential to send weight-loss clients back to personal trainers.

Both patients and insurance companies want the best results from the drug, and exercise plays a vital role in its long-term success. Personal trainers can expect many new clients from this population, especially from those who no longer take the drug and did not exercise, as they look for lifestyle interventions to maintain weight loss. 

Personal trainers play a pivotal role in the success of GLP-1 users to guide and encourage exercise. Exercise can protect against many negative physiological effects, such as muscle and bone loss and increased resting heart rate. It is also intended to be used in conjunction with GLP-1, leading to much higher weight loss rates. Weight maintenance is the hardest part, however, and exercise has been shown to prevent weight regain after discontinued use of the drug. 

On a psychological note, exercise increases self-efficacy, preventing feeling unhealthy, which is all too common of a false belief many people have. 

Until more specific exercise guidelines for using a GLP-1 are released, personal trainers should treat GLP-1 users similarly to weight loss clients. Personal trainers can use the typical weight loss guidelines, such as 150 or more minutes a week of moderate-intensity cardio and, very importantly, at least two resistance training sessions a week. 

References

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