Table 4.

Summary table of current investigations determining validity of various wearable technology devices compared to a criterion measure for heart rate.

Reference	Subjects	Activity	Device(s)	Validity - MAPE	Validity – correlation to criterion
An et al. 2017 (1)	N = 35 (18 females, 17 males), 31.0±11.8 yrs	Treadmill: 3 minutes at 3.2, 4, 4.8, 5.6, 6.4, 8.04 km/h Over-ground: indoor track 24 hr Free-living	Fitbit Zip, Withings Pulse, Jawbone UP 24, Basis B1 Band, Garmin VivoFit, Sense Wear Mini, Fitbit Flex, Misfit Shine, Polar Loop, Nike + FuelBand	All devices and treadmill speeds = 8.2% All devices over-ground = 9.9% Free-living = 18.48%	Fitbit Zip & Withings Pulse r=1.0 > Jawbone UP24 & SenseWear Mini r=0.9 > Basis B1 Band, Fitbit Flex, Misfit Shine, & Nike+Fuel Band r=0.8 > Garmin VivoFit & Polar Loop r=0.7
Chen et al. 2016 (2)	N = 30 (15 females, 15 males), 21.5±2.0 yrs	Treadmill: 5 minutes at 3.2, 4.8, 6.4, 8.04 km/h Other: 6 Simulated daily activities	Fitbit Flex, Garmin VivoFit, Jawbone UP,	Absolute Percent Error (APE) all devices and speeds = 1.5–9.6% APE for 8.04 km/h with all devices < 2.5%	Devices over counted steps At 4.8 km/h: JawboneUP = 64.4 Gamin Vivofit = 87.8 Fitbit Flex = 157 And at 8.04 km/h: JawboneUP = 54.6 Gamin Vivofit = 85.4 Fitbit Flex = 79.1
Fokkema et al. 2017 (8)	N = 31 (15 females, 16 males), 32.0±12.0	Treadmill: 10 minutes at 3.2, 4.8, 6.4 km/h	Garmin VivoSmart, Fitbit Charge HR, Polar Loop, Apple Watch Sport, Pebble Smartwatch, Samsung Gear S, Misfit Flash, Jawbone UP Move, Flyfit, Moves	All devices = 0.0–26.4% Best Devices: Garmin VivoSmart = −0.2–9.0% Fitbit Charge HR = −.07–5.2% Apple Watch Sport = 0.0–1.9%	All devices ICC = −0.02–0.97, Slow 3.2 km/hr ICC = 0–0.95 Average 4.8 km/hr ICC = 0–0.98 Vigorous 6.4 km/hr ICC = 0–0.92
Huang et al. 2016 (10)	N = 40 (15 females, 25 males), 23.9±2.8 yrs	Treadmill: 3 minutes at 3.2, 4.8, 6.4 km/h Flat ground testing Stairs testing	Nike+FuelBand SE, Jawbone UP 24, Fitbit One, Fitbit Flex, Fitbit Zip, Garmin Vivofit, Yamax CW-701, Omron HJ-321	All devices = 0.1–16.7% At level walking all <1% except Garmin Vivofit, Fitbit Flex, & Nike+FuelBand SE All devices on stairs = 1.1–7.9%, except Nike+FuelBand SE = 34.3%	Trends of systematic bias for Jawbone UP 24 (slope = 0.4, R = 0.20), Garmin Vivofit (slope = 0.4, R = 0.19), Fitbit Flex (slope = 0.8, R = 0.49) and Nike+FuelBand SE (slope = 1.1, R = 0.54)
Nelson et al. 2016 (13)	N = 30 (15 females, 15 males), 48.9±19.4 yrs	5 minutes of self-paced sedentary, household, ambulatory, walking, jogging, stairs, cycling	Fitbit One, Fitbit Flex, Fitbit Zip, Jawbone UP 24, Omron HJ- 720IT (criterion)	All monitors for Household activities = 54–79%, Ambulatory activities= 3–6%, Walking = 2–11%, Jogging = 3–8%, Cycling = 70–93%	Sedentary: No monitors significantly differed from researcher step count, Household: Only Fitbit One not statistically different from Omron, Ambulatory: FitbitZip significantly more steps than Omron, Walking, Jogging, Stairs: no statistical difference from Omron except FitbitFlex Cycling: Only Jawbone significantly different from Omron