# How to use Apple Watch support features for fitness > Updated: 2026-07-04 · Source: https://dorsi.ai/topics/apple-watch-support Your Apple Watch flags AFib with 71% sensitivity against standard ECG. That's good, but doesn't tell you what to do next. The same goes for training… Apple Watch support means two things to me: your watch syncing reliably with Dorsi (heart rate, HRV, sleep, workouts, all of it) and a human you can talk to when something breaks. Email me directly at support@dorsi.ai. I answer within 24 hours, usually faster. This page covers exactly what Dorsi pulls from your Apple Watch and how to fix common syncing issues. Your Apple Watch flags AFib with 71% sensitivity against standard ECG. That's good, but doesn't tell you what to do next. The same goes for training readiness: HRV drops can mean overreaching or just that you had coffee. Making sense of these alerts requires context. Dorsi provides that context, analyzing your wearable data alongside your training history and sleep. No green-yellow-red algorithms. Instead, it adapts your daily plan, whether you have 20 minutes or an hour. This page covers the key questions users ask about Apple Watch support: how to pair, what metrics matter, and when to trust the watch versus your own body. ## How do I fix a no-sync workout? When your Apple Watch fails to sync a workout to your phone, the fix is usually simpler than you think. Check both devices have Bluetooth on. Restart the app before restarting the watch. If that fails, unpair and re-pair the watch via the Watch app on iPhone. That resolves 80% of sync issues. Don't waste time on forums before trying these. ## Calibrate your watch for accurate distances The watch uses GPS and accelerometer for distance tracking. If your runs or walks show wonky distances, recalibrate: go to a flat outdoor track, open the Workout app, set to Outdoor Walk, and walk for 20 minutes at your normal pace. Repeat for Outdoor Run. This trains the stride model. Do it once a month if you see drift. ## When should I replace the battery? Batteries degrade over time. If your watch dies before midday or can't last through a 90-minute workout, it's time for a battery service. Apple charges $79 for most models. Check battery health in Settings > Battery > Battery Health. Below 80% capacity, replacement is worth it. Don't wait until it can't keep up with your training.