GLP-1 Weight-Loss Medicines and Exercise: What Fitness Professionals Should Monitor

EFWA KNOWLEDGE HUB · NUTRITION & WEIGHT MANAGEMENT

By Dr Mert Eray Onen, Founder & Academic Director, EFWA · ORCID 0000-0001-8510-7293

Estimated reading time: 7 minutes

Fitness professionals can support clients who use GLP-1 or dual GLP-1/GIP weight-management medicines by coaching appropriate exercise, observing changes in function and recovery, and staying firmly within professional scope. They should not advise on dose changes, stopping treatment or managing medicine-related symptoms. Those decisions belong with the prescribing clinician.

Medicines such as semaglutide and tirzepatide have changed conversations about weight management. They can produce clinically meaningful weight loss for eligible people, but body weight is only one part of physical health. Strength, aerobic fitness, mobility, confidence and the ability to perform everyday tasks still need attention. This creates a legitimate role for a suitably qualified fitness professional—provided that role is clearly defined.

What do GLP-1 medicines change—and what do they not replace?

GLP-1 receptor agonists, and medicines that act on both GLP-1 and GIP pathways, influence appetite and metabolic regulation. Current NICE guidance for semaglutide and tirzepatide places these medicines alongside a reduced-calorie diet and increased physical activity for defined eligible groups. The MHRA’s guidance, updated on 5 February 2026, describes them as prescription-only medicines and stresses that treatment changes belong with a healthcare professional.

Exercise therefore remains relevant, but not simply because it might change the number on the scale. Its value includes maintaining or improving physical capacity. In a 2026 secondary analysis of a randomised trial, structured exercise—alone or combined with liraglutide—improved cardiorespiratory fitness after diet-induced weight loss, whereas liraglutide alone did not produce the same fitness improvement. This is useful evidence, but it is drug-specific and should not be treated as proof that every programme produces the same result with every medicine.

Why the scale is not enough

Weight loss includes changes in more than one tissue compartment. Research reports often use terms such as lean mass or fat-free mass; definitions vary by measurement method, and neither term is synonymous with skeletal muscle. These measures can also reflect water, organs, bone and other tissues. A change in lean mass on a scan does not, by itself, tell an instructor whether a client has lost meaningful strength or function.

For coaching purposes, a broader picture is more informative. A client may be lighter while also becoming stronger, walking further or completing daily tasks more comfortably. Conversely, repeated reductions in training performance, recovery or participation should not be dismissed merely because scale weight is falling. EFWA’s educational position is that weight-management coaching should track capability as well as body mass.

The EFWA SCOPE framework

The SCOPE framework is an EFWA teaching aid, not a medical protocol. It helps fitness professionals organise what they can responsibly observe and what must be referred.

S — Start with the training context

Use normal pre-exercise screening and establish the client’s current activity, training experience, goals and any restrictions communicated by their healthcare team. Ask whether the prescriber has given instructions that affect exercise. Do not attempt to interpret laboratory results or decide whether a medicine is suitable.

C — Calibrate from current capacity

Do not assume that a client can—or cannot—tolerate a particular session simply because they use a GLP-1 medicine. Begin from observed ability. Select loads, exercise complexity and work-to-rest ratios that allow sound technique and a manageable effort. Progress should be based on repeatable performance rather than a predetermined timetable.

O — Observe function and recovery

Useful non-clinical measures include attendance, repetitions completed with stable technique, perceived effort, recovery between sets, walking or cycling tolerance, and simple functional tasks relevant to the client. Review trends rather than reacting to one unusual session. The purpose is better programme adjustment within the instructor’s competence, not clinical surveillance.

P — Protect professional boundaries

A fitness professional must not recommend changing a dose, pausing treatment, switching products or obtaining a medicine from an unregulated source. Nor should an instructor diagnose the cause of symptoms. Medication questions go to the prescriber or pharmacist. Nutrition support must remain within the professional’s qualification and local scope; complex dietary needs warrant referral to a registered dietitian or appropriate clinician.

E — Escalate when the question becomes clinical

If a client reports a new or concerning symptom, cannot train as usual, or asks whether treatment should be altered, pause the coaching decision and direct the question to the healthcare professional responsible for the medicine. The instructor can document what occurred during the session without attempting a diagnosis. In an urgent situation, follow local emergency procedures.

A worked coaching example

Consider a client who has recently started medical weight-management treatment and wants to preserve strength. Their trainer establishes a baseline using several submaximal exercises, a comfortable walking task and ratings of session effort. The first block includes whole-body resistance training plus aerobic activity matched to present tolerance, preference and relevant clinical advice. The precise prescription is individual rather than medicine-specific.

Across several weeks, body weight falls and exercise attendance remains consistent. The client performs more controlled repetitions at the same load and reports that stairs feel easier. The coach records these functional gains rather than claiming that they prove muscle has been preserved. If performance repeatedly declined or symptoms disrupted training, the next action would be a conversation with the prescribing team—not an improvised medication or nutrition intervention.

What is established, emerging and interpretive?

• Established evidence: licensed weight-management medicines are prescribed for defined eligible groups and used with dietary and physical-activity support. Exercise can improve fitness and function independently of scale weight.
• Emerging evidence: research on the best exercise programme during treatment is developing. Results from one medicine, population or body-composition method cannot automatically be generalised to all clients.
• Expert interpretation: combining simple performance, function and recovery measures gives a fitness professional a more useful coaching picture than scale weight alone.

For a broader discussion of resistance training and dietary protein during intentional weight loss, read EFWA’s guide to preserving muscle during weight loss. Students and professionals can explore further evidence-informed resources in the EFWA Knowledge Hub.

Evidence limitations

Direct trials combining modern weight-loss medicines with well-described exercise programmes remain limited. Studies vary in medicine, treatment duration, participant characteristics, exercise supervision and methods used to estimate body composition. The cited exercise trial used liraglutide and does not establish identical effects for semaglutide, tirzepatide or every client. Fitness professionals should therefore avoid universal claims about muscle preservation, performance or the “best” programme. This article supports professional education and does not replace individual clinical care.

References

1. European Medicines Agency. (n.d.). Mounjaro. https://www.ema.europa.eu/en/medicines/human/EPAR/mounjaro
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5. Medicines and Healthcare products Regulatory Agency. (2026, February 5). GLP-1 medicines for weight loss and diabetes: What you need to know. https://www.gov.uk/government/publications/glp-1-medicines-for-weight-loss-and-diabetes-what-you-need-to-know/glp-1-medicines-for-weight-loss-and-diabetes-what-you-need-to-know
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7. National Institute for Health and Care Excellence. (2023). Semaglutide for managing overweight and obesity (TA875). https://www.nice.org.uk/guidance/ta875
8. National Institute for Health and Care Excellence. (2024). Tirzepatide for managing overweight and obesity (TA1026). https://www.nice.org.uk/guidance/ta1026