About 12 out of 15 of the best fitness apps actively share your personal data with third parties, de-facto selling out your privacy. Strava and Fitbit are among the most data-hungry, collecting 84% of all potential data points.

These are some of the worrying findings from new research released by Surfshark, one of the best VPN services on the market, after looking at data collection and sharing practices of the most popular fitness mobile applications.

Strava and Fitbit came out as the most data-hungry apps, both gathering 21 unique types of data. In comparison, the most private workout application, Centr, collects just three types of data (User ID, Product Interaction, and Crash Data) with only one of these contributing to user tracking.