Fitbit said its active user base passed 25 million in 2017, as it also talked-up engagement among its network.

The company said its growth “demonstrates both the health of the wearables category and retention of Fitbit users”. There have been question marks over the future for this market – particularly single-purpose health bands – with Fitbit itself not immune to the challenges.

Retention and engagement are seen as key challenges for fitness bands.

The Charge 2 band, Fitbit said, is the top selling fitness tracker in the US, with Amazon stating it was one of its top sellers in the health and fitness category over the Christmas holiday sales period.

Following the introduction of the Ionic smartwatch in 2017, the company argued it is “well positioned to succeed in the evolving wearables category given its range of devices including both trackers and smartwatches, price points, broad compatibility across Android, iOS and Windows, and long battery life”.

Fitbit said more than 20 million people are using the Feed feature within the Fitbit app and users have joined groups more than 4.7 million times, covering topics such as running, swimming, diabetes or heart health.

“We see continued demand for trackers, powered by the enterprise and healthcare sectors, and we strategically entered the smartwatch category with Fitbit Ionic at a time when consumers are moving to smarter, fuller featured devices,” said James Park, Fitbit co-founder and CEO.