The Department of Defense (DoD) is studying security issues raised by physical conditioning trackers that also can be used to track servicemembers' whereabouts. The concern comes from a 'heat map' posted by Strava, the makers of a fitness tracking application, that shows the routes servicemembers run or cycle in their daily exercises. These maps can show military bases and may be used to target individuals. The heat map incident re-emphasizes the need for servicemembers to be cautious about what data to share via wearable electronic devices. Soldiers and civilians who are interested in learning about more ways to protect their online presence can study the U.S. Army's Social Media Handbook and read this Military.com article.