Who knows where you ran last week? If you're privacy-minded, perhaps just you... and your running app. But our fitness apps often share more information than we realise. The Strava app, and now Polar Flow, have released maps that gave away potentially sensitive military locations.

This week, it was reported that fitness app Strava had published data that allowed ordinary citizens to determine the locations of secret military installations around the world. Strava publishes heatmaps showing the most popular running and cycling routes used by professional and amateur athletes who use their platform. A uni student looked at the heat maps in several conflict zones and was able to ascertain the locations of military bases from his observations. But the blame isn't with Strava - the personnel involved are the problem.

Sharing your running and cycling routes is the whole point of using Strava - you can see whether you're the fastest in your neighbourhood at climbing that big hill, or take on a friend's favourite running route to see how you compare. But this weekend, Australian analyst Nathan Ruser pointed out that the app's heatmap of popular routes reveals, oops, data about military bases and the people who are stationed there.