Wear Radar

Fitbit SensevsPolar Grit X

40d vs 6d
battery life
Polar Grit X lasts longer
$550
price gap
Fitbit Sense cheaper
31g
lighter
Fitbit Sense
2
more health sensors
Fitbit Sense
Fitbit Sense
Buy/Wait:bad

Overdue for a refresh — no successor announced yet. Prices should be at their lowest

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Polar Grit X
Buy/Wait:bad

Late in cycle — a new model is likely coming

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Fitbit SensePolar Grit X
Pricing
Starting price$199$749
Subscriptionℹ️ Optional — $79/yr✓ None
Hardware
Weight26g57g
Water resistance50m100m
Battery6 days40 days
Always-on display
GPS
Cellular
PlatformiOS & AndroidiOS & Android
TierSmartwatchSports GPS
Buy timing
ReleasedSep 28, 2022Apr 11, 2024
Cycle advicebadbad
Deals advicegoodgood
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Health Sensors

Fitbit Sense only
3 exclusive sensors
ECGDetects irregular heart rhythms (AFib)
EDA / StressSkin conductance sensor measuring stress responses
Skin TempOvernight changes linked to illness or cycle tracking
Both
3 shared
SpO2Blood oxygen saturation, tracked during sleep
Heart RateContinuous or on-demand pulse tracking
HRVHeart rate variability — stress & recovery scores
Polar Grit X only
1 exclusive sensor
Running PowerWrist-based watt output — tracks effort independent of terrain

Why buy each?

Fitbit Sense

Continuous EDA stress tracking

The EDA (electrodermal activity) sensor tracks physiological stress throughout the day — a feature absent from most competitors at this price.

6 months Fitbit Premium included

Comes with Fitbit Premium for advanced sleep analysis, HRV trends, stress management scores, and personalised health insights.

6-day battery, works with iPhone

Unlike Apple Watch or Galaxy Watch, Sense 2 pairs with any smartphone and runs 6 days before charging.

Polar Grit X

40-day battery for trail and ultra runners

Five times the battery of the Vantage V3 — enough for week-long mountain stages or ultramarathons without charging access.

Hill splitter auto-detection

Automatically segments your run by uphill and downhill sections, calculating pace and power for each — essential for mountain race training.

Wrist running power at mid-range price

Running power without a chest strap or foot pod — Polar's key differentiator versus Garmin at this price tier.

Quick Winner

The right pick depends on what you optimize for.

For the budget
Fitbit Sense wins

$436 vs $749 over 3 years · no required subscription.

For battery life
Polar Grit X wins

40 days vs 6 days battery.

For health depth
Fitbit Sense wins

6 sensors.

For daily comfort
Fitbit Sense wins

26g · no required subscription.

Bottom Line

Technical gaps
  1. Sense-only sensors: ECG, EDA / Stress, Skin Temp.
  2. Grit X-only sensors: Running Power.
  3. Weight. Sense is 31g lighter — relevant for all-day comfort and sleep.
  4. Water resistance. Grit X rates 100m vs 50m on Sense.
Commercial gaps
  1. Hardware cost. Sense is $550 cheaper upfront ($199 vs $749).
Pick the Fitbit Sense if…

Health-conscious users on any platform who want continuous stress monitoring (EDA sensor), ECG, and Fitbit's deep wellness coaching — without paying Galaxy Watch or Apple Watch prices. Particularly strong for iPhone users who want serious health tracking at under $250.

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Pick the Polar Grit X if…

Trail runners, hikers, and outdoor athletes who want Polar's analytics with significantly longer battery life than the Vantage V3. The titanium case and sapphire glass make it suitable for technical terrain where watch durability matters.

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