• by Mark Walsh  @markfwal, April 11, 2014

How big the wearables market will be is a subject of debate. Some see enormous potential for intelligent accessories that do everything from tracking our vital signs to displaying apps, all while making a fashion statement. Others aren’t so optimistic.

Research firm IDC has weighed in with its own outlook, suggesting the market is only now getting beyond the early adopter phase as more functional and stylish products start to gain traction. It says health and fitness-related devices such as the Nike+ FuelBand, Jawbone UP and FitBit will lead the nascent market through 2018.

Specifically, IDC forecasts shipments of wearable devices overall will surpass 19 million units this year and grow at an annual rate of 78.4% to 111.9 million units in 2018. For comparison’s sake, consider more than 1 billion smartphones were shipped last year, and 217 million tablets worldwide.

Apart from fitness bands, which IDC refers to as “complex accessories,” which usually operate in connection with other devices like a smartphone, tablet or a PC, is a segment it calls “smart accessories.” This includes smartwatches like the Samsung Galaxy Gear Fit that let users add third-party apps that provide more robust interaction.

“While not quite ready for prime time, these devices will take longer to gain acceptance as awareness increases and the offerings improve. A third category IDC terms “smart wearables,”symbolized by Google Glass, function with fully autonomy from other devices except to access the Internet. To succeed, they have to get people to shift to a new type of user experience and a wide selection of apps.

That means being able to cross the street while checking Gmail, using Google Maps and reading The New York Times via a head-mounted display. Try that in Times Square.

When it comes to brands in the wearables space, an IDC survey of more than 50,000 consumers in 26 countries found Samsung was the most trusted name, ahead of Apple, Sony and Google. Apple will reportedly introduce a long-rumored iWatch as earlier as next quarter, but the company hasn’t made any official announcement about launching a smartwatch.

For his part, Ramon Llamas, research manager, mobile phones, at IDC, doesn’t expect Apple will enter the wearables market until next year. “Apple is good at standing on the shoulders of those that have gone before them (see iPhone, iPod), and those companies can suffer the slings and arrows of critics and end users. Look at how much criticism Samsung took with the first Gear watch,” he wrote in an email.

For now, Apple enthusiasts will have to settle for the company’s earphones.