Reply: Matters Arising ‘Investigating sources of inaccuracy in wearable optical heart rate sensors’
Brinnae Bent, Oana M. Enache, Benjamin A. Goldstein, Warren A. Kibbe, Jessilyn Dunn
Abstract
This is a response to the Matters Arising (MA) that examines our original article, ‘Investigating inaccuracies in wearable optical heart rate sensors’ 1 . We performed this original study to address the concern that there was inadequate published research on the potential effect of skin tone on wearable device accuracy. The central hypothesis tested in the original study was that darker skin tones have decreased photoplethysmography-based heart rate measurement accuracy as compared with lighter skin tones. The MA suggests improvements surrounding two aspects of the original study: the sample size and the use of the Fitzpatrick skin tone (FP) scale to categorize skin tones. The original study was designed and powered according to the above hypothesis. We acknowledge that visual skin tone scales are imperfect, and that a study can never prove the null hypothesis to be true. We, too, encourage more work examining wearable device accuracy across skin tones. In this reply, we aim to address questions surrounding the sample size, covariates, and choice of skin tone scale in the original article.