Wrist-worn fitness trackers are becoming increasingly popular. However, research has shown that the reliability and accuracy of these devices can vary. Darker skin tone has been suggested as one cause of error among these Light Emitting Diode (LED) based measurement devices. The purpose of this study is to determine whether skin tone has an effect on the accuracy of heart rate measurements in these wearable devices. Participants will be recruited by word of mouth at Southern Utah University (SUU), and through the SUU Office of International Affairs. Demographics will be recorded, and participants must be apparently healthy adults with a BMI less than 30 kg/m². To classify skin tone, pictures of the dorsal side of the wrist will be taken for each participant and classified by two separate investigators at a later time using Felix Von Luschan’s chromatic scale (VLCS). In addition, a different investigator will classify the skin phototypes of all participants using the Fitzpatrick skin phototypes criteria. The average VLCS score must match the Fitzpatrick classification for participants to be included. Participants will then be grouped based on their Fitzpatrick category I-VI with approximately ten in each classification group. Participants will wear the fitness trackers (Fitbit Ionic, Polar Vantage M, and Garmin Vivoactive 3) during 15-20 minutes of rest and 15-20 minutes of submaximal cycling at a perceived exertion of “moderately hard”. Heart rate measurements from the trackers will be compared to data from a polar chest-strap heart rate monitor as the criterion measure. Heart rate error values will be compared across classification groups for each device using ANOVA to determine if skin color impacts the accuracy of heart rate measurements in each group for each device. Results are yet to be determined.
