Measurement · Moderate evidence
Limitations of Smartwatches and Wearables
Smartwatches help monitor trends, but energy expenditure and other metrics can carry error and vary by device and activity.
Systematic review and meta-analysis · 1 source · 2 min
What the studies show
- Steps and heart rate are the most reliable metrics; energy expenditure is the least.
- Error varies by device, activity, and intensity.
- Trends are more useful than absolute values.
How Letz applies it
Exercise calories from wearables appear as context and are never added to the target; the adaptive TDEE already absorbs real expenditure.
Who it applies to
Consumer wearables used in daily life.
Limits
Results from one brand or metric do not automatically transfer to all sources.
Sources
- Chevance et al., JMIR mHealth and uHealth, 2022 DOI 10.2196/35626
More in Measurement
- Limitations of Image-Based Dietary AssessmentPhotos can make logging easier, but energy and portion sizes carry significant error; user review remains necessary.