By Dave Sebastian

Amazon.com Inc. rolled out Amazon Halo, a health and wellness tracker that the company said also tracks its users' emotions, in its latest foray into wearable products as the company seeks to expand its reach into users' everyday lives.

The wristband and app track body-fat percentage, heart rate and its users' activity and sleep, among other features, Amazon said Thursday. The product, Amazon's first entry into the health and wellness space, is available for early order in the U.S. starting Thursday.

The e-commerce giant said the Halo app could monitor its users' social and emotional well-being under the "Tone" feature by analyzing voice, offering insights into their "energy and positivity." Users would also be able to consult the app for workouts and healthy habits, supported by content from Amazon as well as 8fit, Harvard Health Publishing, Mayo Clinic and other sources.

Amazon said the product's battery lasts up to seven days and fully charges in under 90 minutes. Users will also have the option of linking their Halo account with third-party programs, such as WW International Inc., formerly Weight Watchers, the company said.

The Seattle company is offering the Halo Band and six months of Halo membership for an initial rate of $64.99, before rising to its regular price of $99.99. The membership automatically renews for $3.99 a month after the initial six months, Amazon said. In comparison, the latest Apple Watch starts at $399, while trackers by Fitbit Inc. start at $69.95. Alphabet Inc.'s Google agreed to acquire Fitbit for roughly $2.1 billion last year.

Amazon said it encrypts users' health data in transit and in the cloud, and body-scan images are removed from the cloud after processing. Speech samples used to analyze a user's voice will also be deleted after processing, the company said.

Separately on Thursday, Amazon said it is opening the Amazon Fresh grocery store to select customers in Woodland Hills, Calif., before it operates for the public in coming weeks. The grocery store has Alexa virtual-assistant features to help customers manage shopping lists and navigate aisles, Amazon said. The company rolled out its checkout-free "Go" technology in a large grocery store earlier this year.

Regulators in the U.S. and abroad have been investigating Amazon's market size and power. Leaders of Amazon, Apple Inc., Facebook Inc. and Google recently appeared at a Congressional antitrust hearing, in which lawmakers questioned the companies' business practices to gain sizable positions in markets from digital advertising to e-commerce.

The company last year incorporated Alexa to products including earbuds, a multifunction oven that can double as a microwave and air fryer and motion sensor.

Write to Dave Sebastian at dave.sebastian@wsj.com