Exact model-family answer directory

Fitbit Sense 2 troubleshooting

Fitbit Sense 2 (FB521): sense 2 (from the Wikipedia page); sense heritage, and a fix for each symptom below.

Sense 2 (from the Wikipedia page)
Released September 23, 2022 with EDA, ECG and SpO2 sensors and stress tracking.
Sense heritage
The original Sense arrived at the end of September 2020 and received FDA approval for its electrocardiogram function.

Not chargingBattery drainPairingNot syncingNotificationsHeart rate

Part of Fitbit wearable model troubleshooting guide

Reviewed records

2 exact answers

Diagnose the exact device problem

Fitbit · not charging

Fitbit Sense 2 will not charge

Open record Fitbit · workout missing

Fitbit Sense 2 workout or activity was not recorded correctly

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Which units this covers, and how to tell yours is one of them

Model numbers and patterns: FB521

Published specification

What is true of this model and changes how you fix it

Model — Sense 2 (health smartwatch)
Fitbit's health-focused smartwatch with the most sensors: continuous EDA (all-day stress), ECG, skin temperature, blood oxygen and heart rate, plus built-in GPS. It has a MICROPHONE (for voice) but NO speaker — so voice input works, but it cannot play call audio; speaker/mic symptoms apply only to the mic side.
No cellular
No cellular — notifications and voice go through the connected phone. 'Cellular not working' does not apply.
Body Response (cEDA)
Its standout is continuous EDA stress tracking via the Body Response sensor; readings need good skin contact, so fit matters.

Where these figures were read. store.google.com/product/fitbit_sense_2_specs?hl=en-US (health smartwatch, continuous EDA, ECG, skin temp, mic; no speaker)

Manufacturer support for this product line. Google Fitbit Help — Fitbit help. Official Fitbit setup, charging, sensor, notification and sync guidance.

Also read for this model. Wikipedia — Fitbit.

Exact questions

Questions that only have an answer for the Fitbit Sense 2

Can I take calls on my Fitbit Sense 2?+

Not with audio on the watch — the Sense 2 has a microphone (for voice commands and quick replies) but no speaker, so it cannot play call audio through the watch. You can see and manage calls from your phone and use voice for replies, but you talk on the phone. So the speaker side does not apply; the microphone does. It also has no cellular, so it relies on your paired phone.