The so-called “heat maps” generated by service members who wear electronic devices while exercising could pose a significant security risk, Pentagon officials fear. The devices probably provide too much information regarding the whereabouts of joggers, and maps of military installations in which they run, Army Col. Robert Manning III told reporters during a Jan. 29 Pentagon press briefing. Potential adversaries could use such data to plan attacks against bases or individuals, he said. Devices made by Strava, in particular, are specifically of concern because they allow users to upload their data to its web site. Other Strava users can use that information to plan their own exercise regimens. The Defense Department is advising all personnel to use the most stringent security settings their devices would allow. In some areas, the devices are not permitted at all.