A modest increase in resting heart rate is a recognised effect of this drug class, and many people notice it as an awareness of their heartbeat rather than anything alarming. What matters is telling that apart from palpitations that come with chest pain, breathlessness or fainting, which are not medication questions and need urgent assessment.
Call emergency services if palpitations come with:
- Chest pain, pressure or tightness
- Breathlessness
- Fainting or near-fainting
- Pain spreading to the arm, jaw, neck or back
- Sweating with any of the above
Contact your prescriber promptly for: a heartbeat that is persistently fast at rest, an irregular or erratic rhythm, episodes that keep recurring, or palpitations alongside dizziness.
For how this fits alongside the other effects of these medications, see GLP-1 Side Effects: The Complete Management Guide.
The recognised class effect
A small rise in resting heart rate has been observed with GLP-1 medications and appears in the prescribing information. For most people it is modest and not something they notice at all.
Where people do notice, it is usually as being more aware of their heartbeat, particularly when lying still at night. That is different from a racing heart, and different again from an irregular one.
The other causes worth checking first
Several things common on these medications produce palpitations independently, and they are more likely explanations than the drug acting on your heart.
Dehydration. A low fluid volume makes the heart work faster. Very common here and easy to correct.
Low blood sugar. In people taking insulin or a sulfonylurea, a racing heart with shakiness and sweating that eases after eating is a classic presentation. Check with a meter rather than guessing.
Electrolyte disturbance. Significant vomiting or diarrhea shifts the salts that govern heart rhythm. This is one of the reasons persistent fluid loss is treated seriously.
Undereating. Very low intake produces palpitations in its own right.
Anaemia and thyroid problems. Both cause palpitations and both are worth excluding with blood tests if symptoms persist.
Caffeine, alcohol and anxiety. Ordinary contributors that do not stop being relevant because you started a new medication.
What to record before you call
This turns a vague symptom into something a clinician can act on.
- Your resting pulse, counted for a full minute while sitting quietly, on several occasions
- Whether the rhythm feels regular or irregular
- How long episodes last and what you were doing
- Whether it relates to your injection day or a recent dose increase
- What you have eaten and drunk
- All your medications, including anything for diabetes or blood pressure
Many phones and watches record heart rate, and those traces are useful even though they are not diagnostic.
If you have existing heart disease
Tell your prescriber before starting, and mention palpitations early rather than monitoring them yourself. The threshold for getting assessed should be lower if you have a known cardiac condition, an arrhythmia history, or take medication affecting heart rhythm.
Dehydration and low blood sugar both present this way, so fluid status and electrolytes are worth ruling out first. Caffeine adds to the effect, as coffee and caffeine notes.
Frequently asked questions
Is a faster heart rate dangerous?
A modest rise is recognised with this class and is usually not a problem in itself. Persistently fast, irregular, or symptomatic needs assessment.
Will it settle?
Many people find awareness of it fades. Persistent or worsening palpitations should be reported rather than waited out.
Should I stop the medication?
Not on your own judgement, unless you are having emergency symptoms, in which case seek care and tell them what you take.
Can dehydration alone do this?
Yes, and it is one of the more common explanations here.
Are smartwatch readings reliable?
Useful for spotting patterns, not diagnostic. Bring the data, but expect proper testing if something looks off.
Why is it worse at night?
Lying still with few distractions makes people more aware of their heartbeat. That awareness is not the same as a change in rhythm.