Polar Flow best for user data privacy Fitbit and Strava the worst
Most people just grab a fitness app and never think twice. But dig into the App Store and you’ll see they don’t all treat your data the same. We looked at popular health and fitness apps and found some are way more grabby than others. Fitbit and Whoop use your data for all sorts of things, while Polar Flow and Apple Fitness barely touch it.
How Apple privacy labels actually work
Every iOS app now includes a section called App Privacy. This lists what types of data the app collects and why. It’s Apple’s attempt to bring structure and transparency to mobile data practices without forcing users to read long policies.
The labels break data into 35 types across 16 categories. Think of things like Name, Email, Health Data, Identifiers, Location, and so on. Each type must be matched with one or more purposes, such as App Functionality, Analytics, Advertising, or Product Personalization.
If a developer declares a type for App Functionality only, Apple assumes the data is used solely to make the app work. If they include anything beyond that, like analytics or marketing, it gets flagged as used beyond core functionality. Apple also has a specific section for tracking. If that appears, it means the app is sharing data across services for advertising or measurement purposes.
To keep things simple, we looked at just three things for each app:
- First, how many data types each app collects in total.
- Second, how many of those are used for more than just app functionality.
- Third, whether Apple shows a tracking section at all.
What we found in the data
All data was gathered manually from the App Privacy sections as of January 13, 2026.
Here’s how it looks:
App name | Total data type | Only for functionality | Used beyond app functionality | Some are used for tracking |
|---|---|---|---|---|
Fitbit | 23 | 5 | 18 | No |
Strava | 21 | 0 | 21 | Yes |
Nike training club | 20 | 4 | 16 | Yes |
Whoop | 17 | 1 | 16 | No |
Mi Fitness | 16 | 11 | 5 | No |
Suunto | 15 | 6 | 9 | No |
Runna | 15 | 11 | 4 | Yes |
Withings Health Mate | 13 | 4 | 9 | No |
Zepp Health | 12 | 10 | 2 | No |
Garmin Connect | 12 | 6 | 6 | No |
Samsung Health | 9 | 4 | 5 | No |
Apple Fitness | 9 | 1 | 8 | No |
Peloton | 7 | 0 | 7 | Yes |
Polar Flow | 5 | 3 | 2 | No |
What stands out is how varied the data use is between apps that might appear similar at first glance. Strava, Nike Training Club, Runna and Peloton all declare tracking under Apple’s rules. That means at least one type of data is used in a way that links it across services or apps for ad-related purposes.
Others like Fitbit and Whoop collect a high number of data types and use most of them beyond pure functionality, but stop short of what Apple defines as tracking. Mi Fitness and Runna sit at the opposite end, with more data locked down for internal use.
Garmin, Samsung and Zepp Health land in the middle. Their apps collect moderate amounts of data, but Apple’s labels suggest they are mostly used within each company’s own ecosystem.
Polar Flow stands out for how little data it collects. It only declares five data types total, and just two are used beyond basic app functionality. That makes it the most restrained app in our whole review. Peloton is also privacy friendly.
What this actually tells us
Of course, Apple’s privacy labels don’t reveal everything. They don’t measure how much data is sent, or how often, or what happens on the server side. But they do make one thing very clear: not all fitness apps treat your data the same way.
Tracking isn’t the same as advertising, and not all data used beyond functionality is bad. But when an app collects 20+ data types and links them to ad purposes or third-party services, that’s useful to know.
This article is based on data compiled by Gadgets & Wearables.
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