Table 1

Checklist of items that need to be considered when planning validity protocols for consumer heart rate wearables

Target population
BMIΟ
Body heightΟ
Skin toneΟ
SexΟ
Sample size calculation via pilot studyΟ
Criterion measure
Chest strap or ECGΟ
Placement according to manufacturer’s instructionsΟ
Index device
Placement according to manufacturer’s instructionsΟ
Pretest preparations
Standardised meal replacementΟ
Control caffeine intakeΟ
Medical screeningΟ
Exclude participants with medication affecting cardiovascular functionΟ
Control for previous intense physical activityΟ
Testing: laboratory conditions
Minimum of 3 walking intensitiesΟ
Minimum of 2 running intensitiesΟ
Minimum of 3 biking intensitiesΟ
Steady-state (2–5 min)Ο
HR kinetics (transitions and recovery)Ο
Validity level
1. Graded ergometer test with a wide range of exercise intensities reported as % of HRmax (or VO2max) including rest and recoveryΟ
2. Graded ergometer test with a wide range of exercise intensities in absolute values (ie, speed/incline, W/rpm) including rest and recoveryΟ
3. Graded ergometer test with a moderate range of exercise intensities as % of HRmax (or VO2max) including rest and recoveryΟ
4. Graded ergometer test with a moderate range of exercise intensities reported in absolute values (ie, speed/incline, W/rpm) including rest and recoveryΟ
5. Graded ergometer test with a low range of exercise intensities reported as % of HRmax (or VO2max) including rest and recoveryΟ
6. Graded ergometer test with a low range of exercise intensities reported in absolute values (ie, speed/incline, W/rpm) including rest and recoveryΟ
Testing: semifree-living (sport-specific) conditions
Intermittent activities (ie, soccer, basketball, etc)
1. Inherent environmental conditions (eg, standard playing field, etc)Ο
2. Inherent no of players includedΟ
3. Inherent duration with a minimum of 15–20 minΟ
Continuous activities (running, walking, biking, swimming)
1. Minimum of three intensities (40 %, 60 %, 80% of HRmax)Ο
2. Inherent duration with a minimum of 2 min of each intensityΟ
Activities with domestic behaviour (doing laundry, gardening, home construction)
1. Minimum of 15–20 minΟ
Testing: free-living conditions
Subject’s wear index and criterion device for a minimum of 24 hoursΟ
Exclude subject’s not presenting HR data above 40% of HRmaxΟ
Exclude recordings missing more than 5% of the data (index or criterion device)Ο
Processing
Criterion measure processing
1. Apply an automated method for filtering ectopic beats and motion artefactsΟ
Index measure processing
1. No post processing of the end-user data is allowedΟ
2. Resampling into a window of 5 s is allowedΟ
Epochs for analysis/window size
1. Sample criterion measure with same epoch as available with the index measureΟ
2. Window size should be 5 s or shorterΟ
Index and criterion synchronisation
1. Automated method for synchronisation (cross correlation or similar)Ο
Statistical analysis
Standard Bland-Altman LoA analysis for steady-state conditionsΟ
Repeated measure LoA analysis for non-steady state conditions (multiple paired observations of HR epochs per individual)Ο
Evaluate within-device precision by comparing the within-person variability in average HR over 5 s windows separately for steady-state activity of at least 2 min durationΟ
  • BMI, body mass index; HR, heart rate; HRmax, maximal heart rate; LoA, limits of agreement; rpm, repetitions per minute; VO2max, maximal oxygen uptake; W, Watts.