Validation of heart rate measured by the consumer-level wearable device Fitbit: a cross-sectional observational study.
Daisuke Higuchi, Yuko Takahashi, Shigeya Tanaka and 1 others
PMID 41209591WHAT IT FOUND
The Fitbit Inspire 3 generally underestimated heart rate by 2.60 beats/min.
Accuracy was high for most tasks, but error exceeded 10% during slow walking. Clinicians should account for this systematic underestimation when prescribing low-intensity exercises.
Key findings
01The Fitbit device showed a mean difference of 2.60 beats/min compared to ECG, indicating a slight underestimation of heart rate.
02Measurement error was acceptable for most tasks, but mean absolute percentage error exceeded 10% during walking at 3.2 km/h and walking with a 3 kg load.
03The study participants were healthy young university students, limiting generalizability to older adults or those with chronic conditions.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The sample consisted only of healthy, young university students, so results may not apply to older adults, people with darker skin tones, higher BMI, or cardiovascular conditions like atrial fibrillation, all of which can affect photoplethysmography accuracy. The study was conducted in a controlled laboratory setting on a treadmill, not in free-living environments where movement artifacts are more common. Sample size was not predetermined.
Declared interests
The authors declare no conflicts of interest. The work was supported by JSPS KAKENHI (Grant Number JP24K14179).
The easy way to misread this
Do not assume the Fitbit is accurate for all clinical populations. The study only tested healthy young adults. Older patients or those with conditions affecting blood flow or skin elasticity may have significantly higher measurement errors.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →