The map, made by Strava Labs, shows the movements of its app users around the world, indicating the intensity of travel along a given path.

In large cities and well-known locations, the highlighted routes are hardly surprising. But paths that were illuminated inside desert compounds in the Middle East or around insurgent-held cities made it clear the data were being gleaned from military users.

"We are going to take a look at the Department-wide policy to ensure that we have operational security and force protection," Pentagon spokesman Colonel Rob Manning told reporters.

"Recent data releases emphasize the need for situational awareness."

On Strava's map, Iraq appears largely dark, indicating limited use of the Strava app, but a series of well-known military bases where American and allied forces have been deployed as part of their war against the Islamic State (IS) group are highlighted in detail.

Similarly in Syria, what appear to be bases in the north -- where US troops are aiding local partners in the fight against IS -- are lit up brightly against an otherwise darkened background.

The concentration of activity at a base or along a patrol route could be used by insurgent groups to plan attacks on military personnel.

Manning said the review would look at the use of all wearable electronics and smartphones. He said commanders already have the tools at their disposal to ensure "force protection."

"DoD personnel are advised to emplace strict privacy settings on wireless technologies and applications, and such technologies are forbidden at specific DoD sites and during specific activities," he said.

Manning said he was not aware of any request to Strava to take down its map.

But the issue could have been fairly easily avoided.

According to Strava, "athletes with the Metro/heatmap opt-out privacy setting have all data excluded" from the mapping project.