Heart Rate: Wrist Against Chest Strap
Where optical wrist sensors are reliable, where they fail badly, and whether you need a chest strap for the training you actually do.
Health and Recovery Tracking
Heart rate, sleep scores, recovery numbers and blood oxygen. Which of it is measurement, which is estimate, and which you should ignore.
These are consumer devices, not medical instruments. Knowing which numbers are measured and which are modelled is the difference between useful training feedback and anxiety with a battery.
Start here
Which Health Metrics Are Worth Tracking
Which numbers on your wrist are measured, which are estimated, and which are entertainment. A plain guide to what to act on.
Read the guideMore in health and recovery tracking
Sleep and Recovery Scores, Honestly Assessed
How sleep staging and readiness scores are produced, how much to trust them, and the point at which tracking recovery starts harming it.
Gear referenced in these guides
Affiliate links. See the disclosure.
Various
Chest strap heart rate monitor
Interval training, and anyone whose wrist readings look wrong
Check priceVarious
Fitness and sleep tracking band
Sleep and daily activity, without wearing a large watch to bed
Check price