Free 78-page report
Your wearable gives you a number. This report shows how far off it is.
Seven brands ranked on eleven metrics, using only the numbers from 71 peer-reviewed validation studies.
No brand wins every metric. Kygo connects them all and uses the most accurate source for each.
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One email with the PDF, then four short follow-ups. Unsubscribe anytime.
- 78 Pages of findings
- 71 Peer-reviewed studies
- 7 Wearable brands ranked
- 11 Metrics compared
Inside the report
Metric charts. Every brand on one chart, ranked by its error.
Brand profiles. Where each brand is best, worst and untested.
Buyer's guide. The pick for sleep, recovery, training and more.
Five numbers from the report
5.96%
Oura Ring 4 overnight HRV error vs chest-strap ECG (Dial 2025).
52.4%
Share of awake time Apple Watch Series 8 caught in a lab sleep study (Robbins 2024, Oura-funded).
+43.8 min
Extra sleep Garmin Forerunner 245 Music counted per night vs a sleep lab.
Over 9%
Calories: no brand came within 9% on the max treadmill test, and weight training errors ran from 41.7% to 114.9%.
6.7% vs 56%
Garmin VO2 max error with a chest strap vs wrist only.
How the medals were decided
- Numbers decide; each sub-measure is ranked and ranks combine with equal weight.
- Brand-funded studies are marked and count unless independent tests disagree.
- Only the feature a buyer gets, and only peer-reviewed tests.
- Newest model with a published number.
- Head-to-head studies beat single-brand studies when they disagree.
- Healthy adults decide the order; clinical samples check it.
Free 78-page report
78 pages, seven brands, one rule: the numbers decide.
Get the full ranking, every brand profile and the buyer's guide in one PDF.
Send me the report
One email with the PDF, then four short follow-ups. Unsubscribe anytime.
No brand paid for this report or saw it before publication. Every figure comes from the paper's own tables.