Apple Watch Heart Rate Not Working? 8 Fixes

1Wear the Watch Higher and Tighter on Your Wrist

Fit is the most common cause of bad heart rate readings — and the easiest fix:

• Wear the watch one finger-width above your wrist bone (not on the wrist bone itself)
• The band should be snug but not cutting off circulation — no gap between the sensor and your skin
• During workouts: tighten slightly more than normal — movement causes the watch to shift
• Loose bands reduce sensor contact by 40–60%

2Clean the Sensor and Your Wrist

The four green LED sensors on the back of the watch need clean contact:

1. Remove the watch and clean the back sensor panel with a slightly damp, lint-free cloth
2. Dry completely before putting back on
3. Clean your wrist too — lotion, sunscreen, sweat residue, and soap all interfere with the optical sensor
4. Never use alcohol wipes or abrasive cloths on the sensor

3Check Heart Rate Settings

Heart rate monitoring may be disabled in settings:

1. Watch app on iPhone → Privacy → Health → Heart Rate → make sure it's ON
2. Watch app → Heart Rate → verify Heart Rate is enabled
3. If you disabled Background App Refresh, heart rate background measurements also stop

4Wrist Detection Must Be On

If Wrist Detection is off, the watch doesn't know it's being worn and won't auto-measure:

1. Watch app on iPhone → General → Wrist Detection → ON
2. Note: turning off Wrist Detection also disables Apple Pay and automatic lock

5Restart Apple Watch

1. Hold the Side button until the power slider appears
2. Drag Power Off to the right
3. Wait 30 seconds, then hold the Side button to restart
4. Put it back on your wrist — the sensor re-initializes on restart

6Update watchOS

1. Watch app on iPhone → General → Software Update
2. Install any pending update
3. Heart rate sensor calibration improvements are included in many watchOS updates

7Check for Tattoo or Skin Interference

This is a well-documented Apple Watch limitation:

• Dark or dense tattoos on the wrist can block the LED light, causing the sensor to misread or show dashes
• Very dark skin tones in combination with very low ambient light can occasionally cause reading delays (rare with newer models)
• Workaround: wear the watch on the opposite (untattooed) wrist, or use a chest strap heart rate monitor paired via Bluetooth during workouts

8Unpair and Re-pair Apple Watch

A full re-pair resets all sensor calibration data and clears software issues:

1. Watch app on iPhone → your watch name → tap (i) → Unpair Apple Watch
2. A backup is made automatically
3. Re-pair the watch and restore from backup
4. After re-pairing, wear the watch continuously for 24 hours — the sensor re-calibrates over time