Fitness App A service member looks at a fitness app on his smartphone at the Pentagon, Feb. 1, 2018. The Defense Department is concerned about a “possible vulnerability” of the use of GPS-enabled electronic devices after a Strava heat map showed the routes of exercise enthusiasts who used the app to track their fitness activities, including at military installations worldwide. DoD photo by Lisa Ferdinando SHARE IMAGE: Download Image: Full Size (1.14 MB) Photo By: DoD photo by Lisa Ferdinando VIRIN: 180201-D-BN624-0001.JPG Photo Gallery