Fitbit, a company that makes wearable devices that monitor fitness activity, says it's changing its practice of selling users' personal data to advertisers after concerns were raised about consumer privacy.

The San Francisco-based company's move comes after U.S. Sen. Charles Schumer of New York asked the Federal Trade Commission to investigate what he called a troubling policy.

Many Americans wear fitness bracelets and monitors or using mobile apps to monitor their activity. Data from the devices can be sold to advertisers or other third parties without the users' consent.

Fitbit says it will no longer sell data that can identify an individual unless the individual has given permission first.

Schumer said Friday that the makers of other tracking devices should follow suit.