Resting Heart Rate, HRV, and Wearables on a GLP-1 Microdose: What the Watch Is Seeing
Three weeks into a protocol the sleeping heart rate on the wrist is up by three beats and the recovery score has gone amber. Both numbers are real, both are expected, and both have a complete explanation. Here is what the drug does to the pacemaker, what weight loss does in the other direction, and which readings deserve a phone call.
1 to 4 bpm
MEAN RISE IN RESTING HEART RATE WITH SEMAGLUTIDE 2.4 MG, PER THE WEGOVY PRESCRIBING INFORMATION
26% vs 16%
SHARE OF SEMAGLUTIDE VERSUS PLACEBO PARTICIPANTS WHOSE HEART RATE ROSE 20 BPM OR MORE AT SOME VISIT
20%
REDUCTION IN MAJOR CARDIOVASCULAR EVENTS WITH SEMAGLUTIDE 2.4 MG IN THE SELECT TRIAL, DESPITE THE HEART RATE RISE
A man who has worn the same ring to bed for two years starts a low dose of semaglutide on a Sunday. By the following Sunday his sleeping heart rate, which had sat at 54 for as long as the app has records, reads 57. A week later it reads 58 and the overnight HRV has slipped from the low 60s to the low 50s. Nothing else has changed. He has not been ill, has not been drinking, and has slept his usual seven hours. He starts to wonder what the medication is doing to his heart.
The answer is well documented and mostly reassuring. GLP-1 receptor agonists raise resting heart rate by a few beats per minute through a direct action on the heart's pacemaker and through the autonomic nervous system, the effect is dose-related, and every large outcome trial of these drugs has shown fewer cardiovascular events rather than more. What is new is the audience. A decade ago a 3 bpm change was invisible to everyone but a trial statistician. Today tens of millions of people wear a device that reports sleeping heart rate and HRV to a decimal place every morning, and a change the label describes as small arrives on the phone as a coloured warning.
This article covers what the prescribing information and the trials say about the size of the change, the two mechanisms behind it, how dose and weight loss shape the number over time, what happens to HRV and sleeping heart rate specifically, what the outcome trials say about safety, and a table that separates the wearable readings that are the drug doing what it does from the ones that belong in front of a clinician.
Key takeaways
- •GLP-1 receptor agonists raise resting heart rate by a mean of 1 to 4 beats per minute at standard doses according to the Wegovy prescribing information, with liraglutide, dulaglutide, and tirzepatide reporting similar ranges, and the rise appears within the first weeks of treatment.
- •The average conceals a spread: 26 percent of semaglutide 2.4 mg participants had a maximum heart rate rise of 20 bpm or more at some visit, compared with 16 percent on placebo, so a subset of people see a much larger change than the mean.
- •Two mechanisms are documented: GLP-1 receptors sit on sinoatrial node cells in human heart tissue, per Pyke and colleagues in 2014, and central GLP-1 receptor signalling raises sympathetic outflow, which Holter studies of liraglutide have confirmed through reduced heart rate variability.
- •The effect grows with dose, from roughly 2 bpm at semaglutide 0.5 to 1.0 mg in the SUSTAIN trials to the 1 to 4 bpm range at 2.4 mg, so a microdose should produce an effect at the bottom of that range that many wearables cannot separate from night-to-night noise.
- •Weight loss pulls the number the other way: surgical weight loss of about 30 kg lowered resting heart rate and raised HRV over one year in the Swedish Obese Subjects substudy reported by Karason in 1999, and in the tirzepatide SURMOUNT-1 trial heart rate rose early and then eased as weight came off.
- •Every major cardiovascular outcome trial of a long-acting GLP-1 receptor agonist reduced major adverse cardiovascular events despite the heart rate rise, by 13 percent in LEADER, 26 percent in SUSTAIN-6, 12 percent in REWIND, and 20 percent in SELECT, but the labels still advise monitoring and reporting palpitations or a sustained increase.
Does a GLP-1 medication raise resting heart rate?
Yes. A small rise in resting heart rate is one of the most consistent findings across the entire GLP-1 receptor agonist class, and it appears in the prescribing information of every long-acting agent. The Wegovy label reports a mean increase in resting heart rate of 1 to 4 beats per minute in participants taking semaglutide 2.4 mg compared with placebo. The Saxenda label for liraglutide 3.0 mg reports 2 to 3 bpm. The labels for dulaglutide and tirzepatide report increases in the range of 2 to 4 bpm. Sun and colleagues pooled the trial data in a 2015 network meta-analysis and found the same 2 to 3 bpm increase for the long-acting agents across type 2 diabetes populations.
The mean is a poor description of what an individual will see. The Wegovy label reports that more semaglutide participants than placebo participants had a maximum change from baseline at any visit of 10 to 19 bpm, 41 percent versus 34 percent, and of 20 bpm or more, 26 percent versus 16 percent. Read carefully, that means a large rise at some point is common in both arms, because heart rate measured at a clinic visit bounces around with anxiety, caffeine, and the walk from the car park, but it is roughly 10 percentage points more common on the drug. A minority of people get a much larger effect than the average suggests, and a wearable, which measures every night rather than every few months, will show that person their own number rather than the trial's mean.
Timing matters for interpreting a wearable trend. Lorenz and colleagues reviewed the heart rate data across the class in 2017 and drew a distinction that the labels do not. Short-acting agents such as exenatide twice daily and lixisenatide produce a transient rise that follows each injection and fades within hours. Long-acting agents such as liraglutide, dulaglutide, weekly exenatide, and semaglutide produce a rise that appears within the first one to two weeks, plateaus, and persists for as long as the drug is taken. Someone on a weekly injection should therefore expect a step change early, not a gradual climb, and a number that keeps climbing past the first month is telling a different story.
Mean rise in resting heart rate by agent at standard maintenance dose, bpm
Midpoints of the ranges reported in each product's prescribing information: liraglutide 2 to 3 bpm, semaglutide 1 to 4 bpm, dulaglutide and tirzepatide roughly 2 to 4 bpm. Individual values vary widely around these means.
The class effect is remarkably uniform. Whichever long-acting agent is used, the mean rise lands between 2 and 3 beats per minute.
Participants with a maximum heart rate rise at any visit, semaglutide 2.4 mg versus placebo, percent
From the Wegovy prescribing information, section on heart rate increase. A large rise at a single visit was common in both arms; the difference between arms is what the drug adds.
- Semaglutide 2.4 mg
- Placebo
Roughly one in four people on the full dose saw a 20 bpm rise at some point. The mean of 1 to 4 bpm is not what a wearable will show that quarter.
Why do GLP-1 receptor agonists raise heart rate?
GLP-1 receptor agonists raise heart rate through a direct action on the heart's pacemaker cells and through an increase in sympathetic nervous system drive, and both are documented in tissue and in people. The direct route was settled in 2014 when Pyke and colleagues, using a monoclonal antibody validated far more carefully than the reagents behind earlier conflicting reports, mapped GLP-1 receptor expression in monkey and human tissue and found it in the cells of the sinoatrial node, the cluster of cells in the right atrium that sets the heart's rhythm. They did not find it on ventricular muscle. A drug that activates receptors on the pacemaker will make the pacemaker fire faster, and that is the simplest explanation for a rise that appears within days.
The second route runs through the brain. Yamamoto and colleagues showed in the Journal of Clinical Investigation in 2002 that stimulating GLP-1 receptors in rats raised heart rate and blood pressure and activated the brainstem neurons that regulate autonomic outflow, and that the effect could be blocked at the level of the sympathetic nervous system. Baggio and colleagues examined both routes together in mice in 2017 and found that the acute heart rate response required the autonomic nervous system while cardiac GLP-1 receptors contributed to the sustained effect. Neither mechanism is complete on its own, and the human picture, a modest steady rise with a shift in heart rate variability toward sympathetic dominance, fits both operating at once.
Two other contributors are worth naming because a wearable cannot distinguish them from the drug. Blood volume falls in the first weeks of any GLP-1 protocol because fluid intake drops alongside food intake and thirst is blunted, and a heart pumping a smaller volume beats faster to maintain output. Mild nausea and the gastrointestinal upset common during titration also raise heart rate through the stress response. Both effects are largest early, both respond to hydration and a calorie floor, and both sit on top of the pharmacological rise rather than replacing it.
Does a GLP-1 microdose raise heart rate less than a full dose?
The evidence points to a dose-related effect, so a microdose should produce a smaller rise, although no trial has measured heart rate at true microdose levels and the honest answer includes that gap. In the semaglutide SUSTAIN programme for type 2 diabetes, the 0.5 mg and 1.0 mg doses raised heart rate by roughly 2 bpm relative to comparators, while the 2.4 mg dose in the STEP programme is described in the label as 1 to 4 bpm. Lorenz and colleagues' 2017 review found the sustained rise with long-acting agents clustered at 2 to 3 bpm at standard doses across the class. The pattern across those data is a shallow dose-response curve: more drug produces more heart rate, but the slope is gentle.
Extrapolating downward, a person taking a quarter to a third of a standard maintenance dose should expect a mean effect somewhere between zero and 2 bpm. That is a real change, and a sensitive wearable with a long baseline can detect it as a trend over weeks, but it is smaller than the typical night-to-night variation in sleeping heart rate, which runs 2 to 5 bpm for most adults depending on alcohol, training, room temperature, and sleep timing. A single elevated night on a microdose means almost nothing. A 14-day rolling average that has shifted upward and stayed there is the drug.
The dose relationship cuts both ways for the subset of people with a large response. Someone whose sleeping heart rate rose 12 bpm on a standard dose has, in effect, run their own dose-response experiment, and a lower dose is a reasonable thing to discuss with a prescriber before deciding the medication does not suit them. The receptor mechanism is the same at every dose; only the magnitude changes.
Illustrative mean rise in resting heart rate by semaglutide dose, bpm
Conceptual curve drawn from the SUSTAIN and STEP trial ranges and the Lorenz 2017 review. The 0.25 mg point is an extrapolation; no trial has measured heart rate at that dose as a maintenance level. Drawn to show the shape of the relationship, not to predict any individual's value.
The slope is shallow. Going from a microdose to a full dose roughly doubles the heart rate effect while multiplying the drug exposure by five to ten.
Why does weight loss pull heart rate the other way?
Losing fat lowers resting heart rate, and after enough weight has come off that effect can cancel or exceed the drug's direct effect, which is why many people on a GLP-1 protocol end the first year with a lower resting heart rate than they started with. The clearest human evidence comes from the Swedish Obese Subjects study. Karason and colleagues reported in the American Journal of Cardiology in 1999 that participants who lost roughly 30 kg through bariatric surgery had a lower resting heart rate and a higher heart rate variability one year later, while matched obese controls who did not lose weight showed no change. The mechanisms are mechanical and hormonal: a lighter body needs less cardiac output, blood volume falls in proportion to body mass, insulin sensitivity improves, and the sympathetic overactivity that accompanies excess adiposity recedes.
The two forces play out in sequence rather than at once. The drug's chronotropic effect arrives within a week or two and plateaus. Fat loss accumulates over months. The result is a heart rate trajectory that rises first and then drifts back, and the tirzepatide SURMOUNT-1 trial reported by Jastreboff and colleagues in 2022 showed that shape: heart rate rose during the early months of treatment and then eased as weight loss accumulated, ending modestly above placebo at 72 weeks. A wearable will show the same arc, and the arc is the reason a heart rate that is up 3 bpm at week three should not be read as the permanent new number.
A microdose produces a smaller version of both forces. The drug effect is at the low end of the range, and the slower fat loss means the counterbalancing decline takes longer to appear. The net line on a microdose is flatter and closer to zero throughout, which is one of the more concrete reasons a low dose tends to leave the morning numbers alone.
Illustrative resting heart rate change over 24 weeks at a standard dose: drug effect, weight loss effect, and net, bpm
Conceptual curves. The drug effect steps up in the first two weeks and plateaus at about 3 bpm, consistent with Lorenz 2017. The weight loss effect accumulates gradually, consistent with Karason 1999 and the SURMOUNT-1 trajectory. Net is the sum. Not a prediction for any individual.
- Drug effect
- Weight loss effect
- Net change
The week-three number is the peak, not the destination. By six months the two effects are roughly balanced in this illustration.
What happens to HRV and sleeping heart rate?
Heart rate variability falls modestly on a GLP-1 receptor agonist, and the change is visible at night, which is exactly when wearables measure it. Kumarathurai and colleagues published the most careful study in Diabetes Care in 2017: a randomised, double-blind, placebo-controlled crossover trial of liraglutide in people with type 2 diabetes and stable coronary disease, using 24-hour Holter monitoring rather than clinic pulse checks. Liraglutide raised 24-hour heart rate by roughly 6 bpm and reduced SDNN, the standard deviation of beat-to-beat intervals and the most widely used HRV summary, with the change present during sleep as well as waking hours. Nakatani and colleagues reported the same direction of HRV change with liraglutide in 2016. Both groups interpreted the pattern as a shift in autonomic balance toward sympathetic tone.
Two things about those findings deserve care before they are mapped onto a ring or a watch. The Holter studies used a full dose of liraglutide in people with diabetes and heart disease, a population with impaired autonomic function to begin with, and the 6 bpm 24-hour figure is larger than the resting figure in the labels because it includes daytime activity. A wearable reports a single overnight HRV number, usually RMSSD rather than SDNN, in a healthier person on a lower dose. The direction should carry over. The magnitude will be smaller, and it will be sitting inside noise that is larger than the signal: a glass of wine, a late coffee, a hard workout, or a short night each depress overnight HRV by 10 to 20 percent in many people.
The practical consequence is that recovery scores go amber in the first weeks of a protocol and most people should expect it. The device is not wrong. It is reporting a sympathetic shift that the pharmacology predicts, and it is not equipped to know that the same shift has been present in every outcome trial that showed cardiovascular benefit. Weight loss improves HRV over months, as the Swedish Obese Subjects substudy showed, so the same arc that applies to heart rate applies here: an early dip, then a slow recovery as fat comes off. Comparing seven-day averages against the pre-protocol month, rather than reacting to single nights, is the only way to see the drug's effect through the noise.
Is a higher resting heart rate on a GLP-1 medication dangerous?
For the population taking these drugs at standard doses, the answer from the outcome trials is no, and it is an unusually well-powered no. A higher resting heart rate is associated with worse cardiovascular outcomes in the general population, which is why the finding attracted attention when it first appeared, and the trials that followed were designed with enough participants and enough years to detect harm if it existed. LEADER, reported by Marso and colleagues in 2016, followed 9,340 people with type 2 diabetes on liraglutide for a median of 3.8 years and found 13 percent fewer major adverse cardiovascular events. SUSTAIN-6 with injectable semaglutide found 26 percent fewer. REWIND with dulaglutide, reported by Gerstein and colleagues in 2019, found 12 percent fewer over a median of 5.4 years. SELECT, reported by Lincoff and colleagues in 2023, followed 17,604 people with overweight or obesity and established cardiovascular disease but no diabetes on semaglutide 2.4 mg and found 20 percent fewer events. Every one of those populations had the heart rate rise. None of them had the harm.
Population reassurance is not individual clearance, and the labels are written accordingly. The Wegovy and Zepbound prescribing information both include a warning on heart rate increase that advises monitoring heart rate at regular intervals, instructs patients to report palpitations or feelings of a racing heartbeat while at rest, and advises discontinuing the medication if a sustained increase in resting heart rate occurs. The outcome trials describe what happens to the average participant; the label describes what to do about the outlier. Both are correct at the same time.
The people for whom the question is not settled are those with pre-existing arrhythmia, particularly atrial fibrillation, and those already on a rate-controlling medication such as a beta blocker, because the trials enrolled relatively few of them and a sympathetic shift is a different proposition in a heart that is already irritable. Anyone in that group should be tracking heart rate with their cardiologist in the loop rather than with a ring alone, and a microdose, which produces the smallest version of the effect, is the more conservative way to start the conversation.
Hazard ratio for major adverse cardiovascular events in the GLP-1 outcome trials
Primary endpoint results from LEADER 2016, SUSTAIN-6 2016, REWIND 2019, and SELECT 2023. Values below 1.0 favour the GLP-1 receptor agonist. Every trial population showed the class-typical heart rate rise during treatment.
The amber line is no effect. Four trials, more than 40,000 participants, and every bar sits to the left of it.
What should a wearable reading prompt you to do?
A sleeping heart rate that steps up 2 to 4 bpm in the first weeks and then holds is the expected signature and needs nothing but a note of the new baseline. A larger jump with a sharp HRV drop, thirst, or lightheadedness on standing is more often dehydration and under-eating, which a GLP-1 medication produces by suppressing thirst and appetite together, and which resolve with fluid and a calorie floor. A number that keeps climbing past the first month or sits above about 90 to 100 bpm at rest is the sustained increase the labels describe and should go to the prescriber. Palpitations, chest discomfort, breathlessness, or fainting are not wearable questions at all.
Before any of those readings is attributed to the drug, the ordinary causes deserve a pass. Alcohol raises sleeping heart rate and lowers HRV for a night or two. Caffeine after mid-afternoon does the same. A hard training session, a viral illness, a hot bedroom, a late meal, and the second half of the menstrual cycle each move the overnight numbers by as much as a standard dose of semaglutide does. The table below matches the common patterns to what is most likely behind them and what to do next. Whatever the pattern, the useful comparison is a seven-day average against the month before the protocol began.
| Pattern | Most likely cause | Practical approach |
|---|---|---|
| Sleeping heart rate 2 to 4 bpm above baseline within the first two or three weeks, then flat | The direct chronotropic effect of the medication on the sinoatrial node | This is the expected pharmacological signature and needs no action. Record the new baseline, keep the dose where it is, and expect the number to drift back down over the following months as fat loss and lower blood volume pull heart rate the other way. |
| Sleeping heart rate 8 to 10 bpm or more above baseline, HRV down sharply, dark urine, thirst, or lightheadedness on standing | Dehydration and under-eating, which raise heart rate independently of the drug | Thirst is blunted on a GLP-1 medication and fluid intake usually falls with food intake. Aim for two to three litres a day with electrolytes, put a floor under daily calories, and re-check the wearable after three well-hydrated days before drawing any conclusion about the medication. |
| Resting heart rate climbing week on week past the first month, now sitting above about 90 to 100 bpm at rest | A sustained increase, which the prescribing information singles out for review | The Wegovy and Zepbound labels advise monitoring heart rate and discontinuing if a sustained increase occurs. Share the trend with the prescriber rather than waiting for a scheduled visit. Thyroid function, haemoglobin, and ferritin are worth checking because low intake can shift all three. |
| Palpitations or a racing heartbeat while sitting still, chest discomfort, breathlessness, or fainting | A symptom cluster that needs a clinical assessment and usually an ECG | These are not wearable questions. The labels instruct patients to report palpitations or a racing heartbeat at rest, and the assessment should happen promptly. Do not adjust the dose on your own in the meantime. |
| HRV 10 to 20 percent below the previous month's average with heart rate only slightly changed | The sympathetic shift documented on liraglutide in Holter studies, plus ordinary noise | Alcohol, late caffeine, a hard training day, short sleep, and illness each move overnight HRV by that much on their own. Compare seven-day rolling averages rather than single nights, and expect HRV to recover partially as weight comes off, as it did after surgical weight loss in the Swedish Obese Subjects substudy. |
2 to 5 bpm
Typical night-to-night variation in sleeping heart rate for a healthy adult, larger than the mean effect of a microdose
7 days
Minimum averaging window for a wearable trend to reflect the medication rather than last night's wine, coffee, or workout
100 bpm
Resting heart rate above which sustained tachycardia is defined and a prescriber conversation is warranted regardless of cause
The watch is right. It just lacks the context.
A GLP-1 receptor agonist speeds the sinoatrial node directly and shifts the autonomic nervous system toward sympathetic tone, and the result is a resting heart rate a few beats higher and an HRV a little lower, arriving within the first two weeks and holding while the drug is taken. The size of the change tracks the dose, which places a microdose at the bottom of a range that is already small. Fat loss then pulls heart rate and HRV back in the other direction over the months that follow, so the week-three reading is the peak of the curve rather than the new normal. Across more than 40,000 people in four outcome trials the heart rate rise coexisted with fewer heart attacks, strokes, and cardiovascular deaths, not more. What remains is the individual: the one in four whose heart rate jumped 20 bpm at some visit, the person whose number keeps climbing past the first month, the person who feels their heart racing at rest. The labels tell those people what to do, and a wearable, used as a trend over weeks rather than a verdict every morning, is a good way to notice that they are one of them.
"Three beats a minute is the pharmacology. Thirty beats a minute is a phone call. The device cannot tell the difference. The trend can."
Frequently asked questions
Does a GLP-1 medication raise resting heart rate?
Yes, by a small amount in most people. The Wegovy prescribing information reports a mean increase in resting heart rate of 1 to 4 beats per minute with semaglutide 2.4 mg, and the labels for liraglutide, dulaglutide, and tirzepatide report similar ranges of roughly 2 to 4 bpm. The average hides a wide spread: in the semaglutide trials, 26 percent of treated participants had a maximum rise of 20 bpm or more at some visit, compared with 16 percent on placebo. The increase appears within the first few weeks of a long-acting agent and persists while the drug is taken, although weight loss tends to pull the number partly back over the following months.
Why do GLP-1 receptor agonists increase heart rate?
Two mechanisms are documented. GLP-1 receptors are expressed on the cells of the sinoatrial node, the heart's natural pacemaker, as Pyke and colleagues showed in human and monkey heart tissue in 2014, so the drug can speed the pacemaker directly. GLP-1 receptor signalling in the brain also raises sympathetic nervous system outflow, which Yamamoto and colleagues demonstrated in rodents in 2002 and which Holter studies in people taking liraglutide have confirmed through reduced heart rate variability. Baggio and colleagues showed in mice in 2017 that both cardiac GLP-1 receptors and the autonomic nervous system contribute, which fits the human picture of a small, steady rise with a shift toward sympathetic tone.
Does a GLP-1 microdose raise heart rate less than a full dose?
The available evidence points that way, although no trial has measured heart rate at true microdose levels. Across the semaglutide development programme, the heart rate increase grew with dose, from roughly 2 bpm at 0.5 and 1.0 mg in the SUSTAIN trials to the 1 to 4 bpm range reported at 2.4 mg. Lorenz and colleagues' 2017 review found that long-acting agents produce a sustained rise of about 2 to 3 bpm at standard doses. A person on a quarter or a third of a standard maintenance dose should expect an effect at the low end of that range, on the order of 0 to 2 bpm, and many wearables will not resolve a change that small from night-to-night noise.
Why does resting heart rate sometimes fall on a GLP-1 medication despite the drug effect?
Because fat loss lowers resting heart rate, and after enough weight comes off that effect can outweigh the drug's direct effect. Karason and colleagues reported in 1999 that surgical weight loss of about 30 kg in the Swedish Obese Subjects study lowered resting heart rate and raised heart rate variability over a year, while obese controls did not change. Lower blood volume, less cardiac work, improved insulin sensitivity, and lower sympathetic tone all contribute. In the tirzepatide SURMOUNT-1 trial, heart rate rose during the early months and then eased as weight loss accumulated, which is the same two forces playing out in sequence.
Does a GLP-1 medication lower HRV?
In the Holter studies available, yes. Kumarathurai and colleagues reported in Diabetes Care in 2017 that liraglutide raised 24-hour heart rate by roughly 6 bpm and reduced SDNN, a standard measure of heart rate variability, in people with type 2 diabetes and coronary disease. Nakatani and colleagues found a similar HRV reduction with liraglutide in 2016. Both findings are consistent with a shift toward sympathetic tone. Wearables that report an overnight HRV or recovery score will often show a modest dip in the first weeks of a protocol, and the dip tends to shrink as weight comes off because weight loss itself improves HRV.
Is a higher resting heart rate on a GLP-1 medication dangerous?
The outcome trials say no for the average patient at standard doses. Every large cardiovascular outcome trial of a long-acting GLP-1 receptor agonist has shown fewer major adverse cardiovascular events despite the heart rate rise: LEADER with liraglutide reduced events by 13 percent, SUSTAIN-6 with semaglutide by 26 percent, REWIND with dulaglutide by 12 percent, and SELECT with semaglutide 2.4 mg by 20 percent in people with established cardiovascular disease and no diabetes. The labels still advise monitoring heart rate, and a sustained large increase, palpitations at rest, or a racing heartbeat is a reason to contact the prescriber. The population data are reassuring; the individual outlier still needs to be looked at.
What does a wearable heart rate reading on a GLP-1 protocol actually mean?
A sleeping heart rate 2 to 4 bpm above the previous baseline that appears in the first two or three weeks and then holds steady is the drug's expected signature and needs no action. A rise of 8 to 10 bpm or more, especially with a sharp HRV drop, thirst, or lightheadedness on standing, is more often dehydration and under-eating, both common on these medications because thirst and appetite are suppressed together. A resting rate that keeps climbing past the first month or sits above about 90 to 100 bpm at rest is the sustained increase the labels describe and should be shared with the prescriber. Compare seven-day averages rather than single nights, because alcohol, caffeine, training, and short sleep each move the numbers by as much as the drug does.
When should a heart rate change on a GLP-1 medication be reported to a clinician?
The prescribing information for semaglutide and tirzepatide instructs patients to report palpitations or a feeling of a racing heartbeat while at rest, and advises discontinuing the medication if a sustained increase in resting heart rate occurs. In practice, a resting heart rate that has risen by more than about 10 bpm and stayed there for several weeks, a resting rate persistently above 100 bpm, palpitations, chest discomfort, breathlessness, dizziness, or fainting all justify a call. Thyroid function, haemoglobin, ferritin, and hydration status are usually worth checking at the same time because reduced intake can push each of them in a direction that raises heart rate on its own.
Clinical references
- Novo Nordisk. Wegovy (semaglutide) injection 2.4 mg: prescribing information, warnings and precautions, heart rate increase. US Food and Drug Administration; 2021, with subsequent revisions.
- Eli Lilly. Zepbound (tirzepatide) injection: prescribing information, warnings and precautions, heart rate increase. US Food and Drug Administration; 2023, with subsequent revisions.
- Novo Nordisk. Saxenda (liraglutide) injection 3 mg: prescribing information, warnings and precautions, heart rate increase. US Food and Drug Administration; 2014, with subsequent revisions.
- Lorenz M, Lawson F, Owens D, et al. Differential effects of glucagon-like peptide-1 receptor agonists on heart rate. Cardiovascular Diabetology. 2017;16(1):6.
- Sun F, Wu S, Guo S, et al. Impact of GLP-1 receptor agonists on blood pressure, heart rate and hypertension among patients with type 2 diabetes: a systematic review and network meta-analysis. Diabetes Research and Clinical Practice. 2015;110(1):26-37.
- Pyke C, Heller RS, Kirk RK, et al. GLP-1 receptor localization in monkey and human tissue: novel distribution revealed with extensively validated monoclonal antibody. Endocrinology. 2014;155(4):1280-1290.
- Yamamoto H, Lee CE, Marcus JN, et al. Glucagon-like peptide-1 receptor stimulation increases blood pressure and heart rate and activates autonomic regulatory neurons. Journal of Clinical Investigation. 2002;110(1):43-52.
- Baggio LL, Ussher JR, McLean BA, et al. The autonomic nervous system and cardiac GLP-1 receptors control heart rate in mice. Molecular Metabolism. 2017;6(11):1339-1349.
- Kumarathurai P, Anholm C, Larsen BS, et al. Effects of liraglutide on heart rate and heart rate variability: a randomized, double-blind, placebo-controlled crossover study. Diabetes Care. 2017;40(1):117-124.
- Nakatani Y, Kawabe A, Matsumura M, et al. Effects of GLP-1 receptor agonists on heart rate and the autonomic nervous system using Holter electrocardiography and power spectrum analysis of heart rate variability. Diabetes Care. 2016;39(2):e22-e23.
- Karason K, Mølgaard H, Wikstrand J, Sjöström L. Heart rate variability in obesity and the effect of weight loss. American Journal of Cardiology. 1999;83(8):1242-1247.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. 2022;387(3):205-216.
- Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine. 2021;384(11):989-1002.
- Marso SP, Daniels GH, Brown-Frandsen K, et al. Liraglutide and cardiovascular outcomes in type 2 diabetes. New England Journal of Medicine. 2016;375(4):311-322.
- Marso SP, Bain SC, Consoli A, et al. Semaglutide and cardiovascular outcomes in patients with type 2 diabetes. New England Journal of Medicine. 2016;375(19):1834-1844.
- Gerstein HC, Colhoun HM, Dagenais GR, et al. Dulaglutide and cardiovascular outcomes in type 2 diabetes (REWIND): a double-blind, randomised placebo-controlled trial. Lancet. 2019;394(10193):121-130.
- Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and cardiovascular outcomes in obesity without diabetes. New England Journal of Medicine. 2023;389(24):2221-2232.
- Shaffer F, Ginsberg JP. An overview of heart rate variability metrics and norms. Frontiers in Public Health. 2017;5:258.
Medical disclaimer. This article is for general educational and informational purposes only. It is not medical advice and is not a substitute for the prescriber or clinician responsible for your care. Nothing here describes a treatment for tachycardia, arrhythmia, atrial fibrillation, hypertension, cardiovascular disease, obesity, type 2 diabetes, or any other condition, and no GLP-1 receptor agonist is approved for any effect on heart rate or heart rate variability. GLP-1 microdosing is an off label approach, no published trial has measured heart rate or HRV at microdose levels, and several charts in this article contain illustrative, conceptual, or approximated values, labelled as such, which should not be read as measured results or as targets. Consumer wearables are not medical devices and their heart rate and HRV readings have not been validated for detecting cardiac conditions. Do not start, stop, or change the dose of any GLP-1 medication, beta blocker, antiarrhythmic, thyroid medication, or any other prescription on the basis of this article. Palpitations or a racing heartbeat at rest, chest pain, breathlessness, fainting, or a sustained resting heart rate above 100 beats per minute requires prompt medical attention. Anyone with a history of arrhythmia, atrial fibrillation, heart failure, or structural heart disease should discuss heart rate monitoring with a cardiologist before starting any GLP-1 protocol.