In the era of GLP-1 medications, it’s easy to fall into the trap of celebrating every pound lost. But if you’re a personal trainer working with clients on GLP-1 receptor agonists like semaglutide or liraglutide, you know that weight loss is only the beginning. In this regard, true transformation isn’t just about what’s coming off the scale; it’s about what’s being built beneath it.

To that end, this article presents a clear case that when training clients on GLP-1s, it is essential to track non-scale metrics. These are the indicators that reveal whether your client is truly improving—not just shrinking. In this next-generation model of personal training, your job is to move beyond aesthetics and help clients reclaim their strength, capacity, cardiovascular resilience, and psychological well-being.

Let’s explore the four most critical categories!

Body Composition: Because Weight Loss ≠ Fat Loss

As alluded to in my previous articles, when a client drops 15 pounds on a GLP-1 medication, the real question isn’t “How much fat did you lose?”—it’s “What amount of muscle did you keep?”

In this regard, preserving lean mass should be priority number one. Studies show that GLP-1 agonists like liraglutide promote fat loss, but muscle mass can be compromised if strength training and protein intake aren’t dialed in (Sattar et al., 2021). In these cases, body composition assessments become essential.

Tools such as DEXA scans and bioelectrical impedance analysis (BIA) provide a much more detailed understanding of health than a simple weigh-in. Additionally, skinfold calipers and waist-to-hip ratios can yield valuable insights when applied consistently. However, caution is advised when using skinfold calipers due to the close physical proximity to clients and the potential variability in accuracy if practitioners do not regularly carry out these measurements or maintain their certifications through reputable organizations, such as the International Society for the Advancement of Kinanthropometry (ISAK), which mandates thorough hands-on training for certification. These tools not only indicate whether your client is becoming smaller but also whether they are gaining metabolic strength.

This is particularly important for older clients or those with sarcopenic obesity, as research has demonstrated that resistance training with elastic bands can significantly enhance muscle mass and physical capacity (Liao et al., 2017). While much of this series has concentrated on traditional free-weight and machine-based resistance training in a gym environment, older clients or individuals with limited resources can effectively utilize band exercises to achieve meaningful training results. Ultimately, the focus should not be on the lightness of the bands but rather on the functional power they are developing.

Functional Fitness: Can They Do More Than Before?

When focusing on older clients, particularly seniors, it’s important to remember that you are not just training a body; you are training a person to achieve their goals in everyday life. This is why functional fitness is one of the most effective yet underutilized metrics that trainers can use. As the American population continues to age in the coming decades, many seniors may prefer at-home personal training services or remote training options. Therefore, it’s crucial for personal trainers to have simple, travel-ready assessments in their toolkit to meet the needs of this demographic.

To best support this population, rather than chase calorie burn, shift your lens to performance. Use tools like:

• The 30-second sit-to-stand test
  
• The 6-minute walk test
  
• Grip strength assessments
  
• Repetition maxes in basic lifts (e.g., goblet squat, incline push-up)
  

These assessments are not just performance tests; they are healthspan indicators. In older populations, functional improvements are directly linked to increased independence, improved mental health, and a reduced risk of falls.

For example, Crhová et al. (2020) found that a three-month strength training program in breast cancer survivors led to marked improvements in not only physical performance but also in psychological health and autonomic nervous system regulation. That’s the kind of total-person transformation we’re after.

To fine-tune load and effort, the Borg Rating of Perceived Exertion (RPE) scale is an excellent tool, particularly when GLP-1 clients experience fluctuations in energy levels. Ultimately, you’re not just pushing them harder; you’re helping them train smarter.

Cardiovascular Health: A Quiet Powerhouse

GLP-1 medications are now well recognized for their cardio-protective effects, particularly in individuals with type 2 diabetes (Sattar et al., 2021). As trainers, we need to honor that by integrating cardiovascular markers into our assessment and progression model.

Hence, easy-to-track metrics that can leverage many popular wearable devices, like Whoop, Oura rings, or Apple watches, include:

• Resting heart rate (RHR)
  
• Blood pressure (BP)
  
• Heart rate variability (HRV)

Improvements in these areas often correlate with enhanced balance of the autonomic nervous system and improved aerobic conditioning. This becomes especially powerful when paired with wearable technology or simple, consistent pulse checks.

According to Schwendinger et al. (2023), accelerometer-based metrics, such as step counts and time spent in moderate-to-vigorous activity levels, are strongly associated with cardiorespiratory fitness. Clients want to feel their hearts working better—and these metrics can help prove that they are.

Finally, let’s not forget that even if your client hasn’t lost a single pound that week, better RHR or BP readings can be celebrated as the life-extending wins they are.

Psychological Variables: The Hidden Progress Markers

Ask any experienced coach, and they’ll tell you: behavior change doesn’t happen in the body first. It occurs in the mind. That’s why tracking mood, motivation, and emotional regulation should be a cornerstone of your check-in process, not just the quantifiable metrics.

This is particularly important for clients on GLP-1s, where the appetite suppression and body changes can sometimes be emotionally disorienting. In this regard, implementing brief weekly check-ins—either written or verbal—on mood, sleep, stress, and energy can uncover powerful qualitative insights that numbers can’t touch.

To illustrate this point, Clifford et al. (2005) demonstrated how cardiovascular rhythms can reveal stress and sleep-related disruptions that may not otherwise be captured. By pairing psychological check-ins with physical monitoring, you create a truly comprehensive feedback loop.

Ultimately, when clients feel more focused, less stressed, and more in control of their habits, they’re not just healthier—they’re more likely to stay the course.

In Summary: Let’s Reframe the Finish Line

Your clients may have started their journey on GLP-1s to lose weight—but that’s not the finish line. In fact, the further they go, the less the weight itself matters.

In this regard, real coaching is centered around performance, functionality, resilience, and well-being. It establishes a strong foundation that not only drives weight loss but also promotes vitality, longevity, and independence. 

By consistently and clearly tracking these non-scale metrics, you don’t just achieve results—you create genuine transformation.

References

Clifford, G., Zapanta, L., Janz, B., Mietus, J., Youn, C., & Mark, R. (2005). Segmentation of 24-hour cardiovascular activity using ECG-based sleep/sedation and noise metrics., 595-598. https://doi.org/10.1109/cic.2005.1588171

Crhová, M., Hrnčiříková, I., Střeštíková, R., Šoltés-Mertová, K., Komzák, M., Kapounková, K., … & Ondračková, A. (2020). Effect of a 3-month exercise intervention on physical performance, body composition, depression and autonomic nervous system in breast cancer survivors: a pilot study. https://doi.org/10.5817/cz.muni.p210-9631-2020-50

Liao, C., Tsauo, J., Lin, L., Huang, S., Ku, J., Chou, L., … & Liou, T. (2017). Effects of elastic resistance exercise on body composition and physical capacity in older women with sarcopenic obesity. Medicine, 96(23), e7115. https://doi.org/10.1097/md.0000000000007115

Sattar, N., Lee, M., Kristensen, S., Branch, K., Prato, S., Khurmi, N., … & Gerstein, H. (2021). Cardiovascular, mortality, and kidney outcomes with GLP-1 receptor agonists in patients with type 2 diabetes: a systematic review and meta-analysis of randomised trials. The Lancet Diabetes & Endocrinology, 9(10), 653-662. https://doi.org/10.1016/s2213-8587(21)00203-5

Schwendinger, F., Wagner, J., Knaier, R., Infanger, D., Rowlands, A., Hinrichs, T., … & Schmidt-Trücksäss, A. (2023). Reference values for accelerometer metrics and associations with cardiorespiratory fitness: a prospective cohort study of healthy adults and patients with heart failure. Current Issues in Sport Science (CISS), 8(2), 029. https://doi.org/10.36950/2023.2ciss029