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GLP-1 drugs like Ozempic and Wegovy have rewritten the weight-loss conversation almost overnight, but nearly everything we hear about them comes down to the number on the scale. What actually happens inside the body, to your heart rate, your sleep and your recovery, has stayed largely invisible. Until now.
WHOOP strapped wearables onto GLP-1 users and matched them against a control group, and the data tells a fuller story than any before-and-after photo ever could: genuine weight loss and more daily movement on one side, a measurable jump in resting heart rate and a dip in recovery on the other. Here is what the numbers reveal, and why they matter whether you are already on one of these drugs or just weighing it up.
What WHOOP's GLP-1 Study Measured
The WHOOP performance science team analysed data from 132 WHOOP members collected between 7 November 2023 and 16 April 2024: 66 members using a GLP-1 medication and 66 matched controls. The study ran for 12 weeks and used causal inference methods to isolate the effect of the medication from normal day-to-day variation.
The results were peer-reviewed and published in the American Journal of Physiology, Heart and Circulatory Physiology, one of the first pieces of real-world evidence on how GLP-1 therapy interacts with physical activity, rather than lab conditions or a drug trial.
Weight Loss on GLP-1, According to WHOOP Data
The headline number is weight loss. 90 percent of GLP-1 users in the study lost at least 5 percent of their body weight within 12 weeks, and the average member lost 10 percent of their body weight over the same period. WHOOP notes that both figures exceed the weight loss typically reported in pharmaceutical trials of the same medications.
Members can track body weight and lean mass on WHOOP directly in the app, which is how the study measured composition changes week to week rather than relying on a single before-and-after weigh-in.
Resting Heart Rate and HRV Changes on GLP-1
Weight loss was not the only change WHOOP picked up. Across the 12-week study, GLP-1 users saw an average 3 beats-per-minute increase in resting heart rate (RHR) and a 6 millisecond decrease in heart rate variability (HRV) on WHOOP. A rising RHR alongside a falling HRV is generally read as added strain on the cardiovascular system, even while the medication is doing its job on the scale.
WHOOP’s own read on the finding is straightforward: these are notable changes in heart health markers, and worth monitoring closely if you are starting a GLP-1 medication, not just tracking your weight.
Why Exercise Blunts the Heart Rate Spike
The more encouraging finding sits inside the same data set. On average, GLP-1 users added 30 minutes of physical activity a week on WHOOP, and the members who exercised more saw smaller increases in resting heart rate than those who did not. WHOOP frames this as the first real-world evidence that staying active can help counteract some of the cardiovascular side effects of GLP-1 therapy, rather than just a general health tip.
Keeping up strength training matters too. WHOOP’s own guidance is that GLP-1 therapies can lead to a reduction in lean muscle mass if you do not actively maintain a strength-training routine, which is why WHOOP recommends resistance work and lean-mass tracking alongside any GLP-1 prescription, not cardio alone.
Tracking Your Own GLP-1 Response
WHOOP now logs GLP-1 use as one of more than 300 behaviours in its Journal feature, so members on the medication can see, in their own data, how their weight, resting heart rate, HRV and activity levels move together week to week rather than guessing from how they feel.
If you are starting or already on a GLP-1 medication, WHOOP is currently offering a free month to try it, which is enough time to see a full month of your own RHR and HRV trend against the benchmarks in this study.
WHOOP GLP-1 FAQs
Ozempic is a brand name for a specific GLP-1 medication. Other common brand names for GLP-1 therapies include Wegovy, Mounjaro and Trulicity, according to WHOOP.
WHOOP analysed 132 members over 12 weeks, 66 using a GLP-1 medication and 66 matched controls, between November 2023 and April 2024. The results were published in the American Journal of Physiology, Heart and Circulatory Physiology.
WHOOP's data found that GLP-1 users who increased their physical activity saw smaller increases in resting heart rate than less active users, suggesting regular exercise may help offset some cardiovascular effects of the therapy.
Yes. WHOOP notes GLP-1 therapies can reduce lean muscle mass if you do not actively maintain a strength-training routine, which is why it recommends resistance training and lean-mass tracking alongside the medication.
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