Highly sensitive information about U.S. soldiers wearing fitness devices was exposed by an Internet map that gave away their location and activities around the world.

The data is found on the Global Heat Map, which the tracking company Strava published in November.

The app can be used on smartphones and jogging devices like Fitbit. Strava has been tracking down activities since 2015, and has over three trillion GPS points uploaded to its system, the company says.

Analysts fear the map could give away the locations of military bases.

"If soldiers use the app like normal people do, by turning it on tracking when they go to do exercise, it could be especially dangerous," Nathan Ruser, founder of the Institute for United Conflict Analysts, tweeted Saturday.

Ruser began tweeting about the heat map Saturday and other military experts and analysts soon weighed in.

Tobias Schneider, a security analyst based in Germany, said the data could help those who want to attack U.S. troops.

"This is a clear security threat," Schneider told The Washington Post. "You can see a pattern of life. You can see where a person who lives on a compound runs down a street to exercise. In one of the U.S. bases at Tanf you can see people running round in circles."

But a Strava spokesman said the heat map doesn't reveal activities that are marked as private.

"Our global heatmap represents an aggregated and anonymized view of over a billion activities uploaded to our platform," the spokesman said. "It excludes activities that have been marked as private and user-defined privacy zones. We are committed to helping people better understand our settings to give them control over what they share."

A U.S. military spokesman told The Post Sunday it was looking into the heat map.