Looking forward GfK forecasts 51.2 million wearables will be bought globally in 2015, three times the size of 2014.

And although health and fitness trackers (HFT) accounted for 77% of overall volume sold, the report predicts smartwatch sales will overtake HFT this year as a number of companies enter the market with new products.

The popularity of HFTs last year was helped by their lower average sales price compared with full-feature smart watches as well as activity tracking being seen as the most important function of a wearable, according to GfK’s survey of 5000 smartphone owners across five countries.

Dr Jan Wassmann, global product manager for wearables at GfK, said: “Many consumers are not yet aware of the additional benefits a smartwatch has to offer. We believe this will now change, driven by the marketing efforts of the industry this year. Added to this, there is a clear convergence of both segments. HFT manufacturers are introducing new models which incorporate smart functions, such as reading notifications and messages. And many new smart watches now come with heart rate sensors and activity tracking capabilities and are being marketed as hybrid fitness devices.”