Open Community Question @LabDetective_OR • 60+M • 50mg Metoprolol Succinate ER • Week 10

▲ 27 Helpful • 2 Peer Replies

My smartwatch shows resting heart rate of 48-52 on metoprolol succinate 50 mg. Is that sensor error or real bradycardia?

Beta-blockers are expected to lower resting heart rate, so a reading of 48-52 bpm can be real. Wrist optical (PPG) sensors can also under- or over-read because of motion, a loose band, cold skin, or tattoos. Check it yourself: sit quietly for 5 minutes, count your radial pulse for a full 60 seconds, and compare it with the watch. If the two agree within about 3-5 bpm, the watch is probably accurate. Call your prescriber promptly if the rate stays below 50 bpm with dizziness, fainting, new shortness of breath, or unusual fatigue. A rate in the 50s without symptoms is often acceptable but should still be reviewed. Do not stop metoprolol on your own. The label carries a boxed warning about abrupt cessation, which can cause rebound tachycardia, angina, or heart attack. Bring 7 days of logged readings to your next visit.

⚕ Pinned FDA / NIH / PubMed Clinical Context • Nattapong Srisai — Literature & Label Auditor

The FDA DailyMed label for metoprolol succinate ER lists bradycardia as a warning and includes a boxed warning against abrupt discontinuation in ischemic heart disease. Dosing runs 25-400 mg once daily, and the dose is adjusted by clinical response, including heart rate and blood pressure.

Connected Clinical Guides: Condition: Atrial Fibrillation Condition: Hypertension Rx: Metoprolol Rx: Apixaban Supplement: Magnesium Taurate Supplement: Magnesium Glycinate

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Verified Peer Replies (2)

@PrairieWalker_KS • Verified Cohort Member • Week 20

Wrist PPG usually tracks resting heart rate well in sitting, still conditions. Accuracy falls with movement, loose fit, and low skin perfusion. If you are on both metoprolol and diltiazem, the labels warn about additive AV-node slowing. Report any resting rate under 50 with symptoms, or any fainting, the same day.

@HighPlainsRancher_WY • Age 60+ • Week 14

I checked my pulse by hand for a full minute against my watch for a week. They matched within 2-3 bpm. I then logged morning and evening readings and showed the list to my cardiology nurse. That was more useful to her than a single screenshot.