Increasing physical activity has been strongly recommended to reduce mortality and healthcare costs. Various wrist‐worn accelerometer‐based devices have been developed to measure level of physical activity, yet little is known about the ability of the devices to precisely estimate physical activity measurements among different locations (i.e., left vs. right; distal vs. proximal).PURPOSEWe, therefore, investigated whether there are differences in heart rates, step counts, and calories estimated from newly developed wearable device (NeoFit) worn at different locations.METHODSThirty‐two healthy subjects (26 ± 6.6 years) participated in both laboratory and free living activities while wearing Neofit at four different locations: right proximal (RP), right distal (RD), left proximal (LP), or left distal (LD). Laboratory activities consisted resting, slow walking (53.6 m/min), brisk walking (107.3 m/min), running (160.9 m/min) on a treadmill, and recovery. Free living activities included lying down, shopping, climbing stairs, laundry, cleaning, working on the computer, stretching, walking, jogging, and sports activity. Repeated measures ANOVAs were performed with a Neofit monitor placement as a within‐subjects factor on a total of 15 laboratory and free‐living activities for each outcome measurement. Bonferroni technique was used to adjust the alpha level of .003 (.05/15). The Greenhouse‐Geisser (G‐G) adjusted F and degrees of freedom were reported.RESULTSThere were no significant differences in heart rates among four different locations in both laboratory and free living activities. However, step counts and calories were significantly different among devices during running: F(2.00, 62.04) = 12.58, G‐G p < .001 and F(1.96, 58.86) = 10.22, G‐G p < .001, respectively. Step counts and calories estimation in NeoFit monitors worn at left arm were markedly higher than those recorded from right arm (steps: LP & LD > RD, LD > RP; calories: LP & LD > RP & RD). In free‐living activities, significant differences in step counts and calories were observed during shopping, F(1.67, 51.54) = 15.90, G‐G p < .001 and F(1.94, 60.01) = 9.07, G‐G p < .001, respectively); laundry, F(1.50, 46.63) = 10.25, G‐G p = .001 and F(2.58, 79.85) = 7.08, G‐G p = .001, respectively); and sports, F(1.31, 39.21) = 10.70, G‐G p = .001 and F(2.28, 70.53) = 15.79, G‐G p < .001, respectively). NeoFit monitors worn at left arm also displayed higher step counts and calories than those from right arm during sports (steps: LP & LD > RP, LP > RD; calories: LP & LD > RD, LP > RP). In contrast to the results of laboratory activities, step counts and calories estimated from right arm were considerably higher than those from left arm during shopping (steps: RP & RD > LP & LD; calories: RP & RD > LP; RP > LD) and laundry (steps: RP & RD > LP & LD; calories: RP > LP & LD; RD > LD). No significant difference between proximal and distal placements was found during all activities.CONCLUSIONWe found that NeoFit placement sites does not markedly affect the estimation of heart rates. The estimation of step counts, and calories during the laboratory‐based and free‐living activities were somewhat different between left and right arms. Further investigation is warranted to examine the accuracy of NeoFit monitors against criterion measures of physical activity.Support or Funding InformationSupported by MEDIPLUS SOLUTION.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.