Resting heart rate explained: what is normal, and what a change means

Resting heart rate (RHR) is the number of beats a minute when you are fully at rest. It is simple, it is measured accurately by nearly every modern wearable, and it moves in response to fitness, illness, alcohol, heat, stress and some medicines. That makes it one of the most useful numbers on the screen.

How wearables define it

Devices do not all mean the same thing by "resting". Oura's readiness contributor uses the lowest heart rate during the night. WHOOP takes it from your sleep. Fitbit, in the large study below, used a proprietary formula intended to approximate the heart rate lying down just after waking. A sleeping minimum will usually sit a few beats below a seated daytime reading, so compare like with like.

The normal range, from 33 million days of data

In 2020 Scripps Research published resting heart rate data from 92,457 US adults who wore a Fitbit for at least 35 weeks between March 2016 and February 2018. Each person contributed a median of 320 days of readings, close to 33 million daily values in all.

The most striking finding was how different healthy people are. Two individuals' normal resting heart rates could differ by as much as 70 bpm. Age, sex, BMI and sleep together explained no more than 10 percent of the differences between people. Within one person, though, RHR was remarkably stable from week to week. That is the core of how to read it: compare yourself with yourself.

Why it matters over the long term

A 2016 meta-analysis in CMAJ pooled 46 prospective studies with 1,246,203 people and 78,349 deaths. Each 10 bpm higher resting heart rate was associated with a 9 percent higher risk of death from any cause (relative risk 1.09) and 8 percent higher cardiovascular mortality. Compared with the lowest category, people above 80 bpm had a 45 percent higher all-cause mortality. These are observational associations, the studies were heterogeneous, and the authors detected publication bias. Fitness, illness and medicines all sit behind the number, so it is a marker more than a cause.

What moves it day to day

How accurate is wearable RHR?

Better than almost any other wearable metric. In a 2021 study against multi-lead ECG, all seven devices tested reported resting heart rate accurately. In a 2022 sleep laboratory study of 53 adults, the mean overnight heart rate bias was within about 1 bpm for Apple Watch, Polar, Oura and WHOOP, with higher error for one Garmin model in that test. A 2020 review of 158 publications concluded that heart rate is measured reasonably well in laboratory settings, with accuracy varying by brand. Error rises during exercise, when motion disrupts the optical signal. At rest, the reading is reliable. See wearable accuracy.

When to pay attention

• A rise well above your usual range for several days with no obvious reason (alcohol, travel, a hard week). Infection is a common cause; after vaccination, the rise in the Scripps data peaked on day 2 and was gone by day 6.
• A sustained rise after starting or increasing a medicine. The Wegovy and Saxenda labels tell prescribers to monitor heart rate at regular intervals and to stop the drug if a sustained increase in resting heart rate occurs. Tell your prescriber.
• A very high or very low RHR with symptoms such as dizziness, breathlessness, chest pain or fainting needs medical attention, whatever the device says.
• A fall over months as you get fitter is the normal, healthy direction.

Logging it

Peptide AI takes resting heart rate from Oura, WHOOP, Garmin, Apple Health or Health Connect through wearable integrations and flags it when it moves outside your own baseline range. Because it sits on the same timeline as the dose log, a rise after a dose step is easy to see and easy to show a clinician.