How Accurate Are Wrist Heart-Rate Sensors, Really?
Wrist sensors are reliable for some things and poor at others. Here is why, and when to trust them.
Wearables
Smartwatches and fitness trackers.
GPS Accuracy in Running Watches: What Causes Drift
Why your watch says you ran further than you did, and what dual-band actually fixes.
Sleep Tracking: What Wearables Can and Cannot Measure
Wearables infer sleep stages from movement and heart rate. Here is what that can and cannot show.
Smartwatch Battery Life: What Actually Drains It
Quoted battery figures assume you leave features off. Here is what actually drains a smartwatch.
Fitness Tracker vs Smartwatch: Which Fits Your Training
The line has blurred considerably. Here is how to work out which one your training needs.
Best Smartwatches for Running
GPS drift and heart-rate accuracy against a chest strap reference.