Wearable tech products are still in their infancy, with companies large and small scrambling for footholds in what most assume will be a monster global market. Earlier this year, CCS Insight predicted that by 2020, 411 million smart wearables will be sold worth $34 billion. Numbers of those magnitudes excite solution-seekers as well as companies that just want to ride the wave to pull out a portion of the revenues. But beyond the projected and very raw numbers, the question remains: Why? What will motivate people to spend money on wearable technology?

YouGov sought the answers to buyer motivation and other key issues in its Wearables tracker study. The group interviewed 2000 non-owners of wearable devices and 1,000 current wearable device owners.The study quantifies market growth by market penetration, key features, future purchase intent, brand awareness and ownership, and other metrics of interest. Let’s assume that some people buy wearables because they’re early-adopters, tech-lovers, style conscious, or just want to be in on what’s hot at the moment. Beyond the consumer-ish motivations, however, wearable tech has to fill a real need or solve an actual problem.

It’s tough to argue that smartwatches, for example, solve a problem with having to look at smartphones when a call or text comes in. It turns out, however, based on the YouGov study, that a desire for better health is what currently drives consumers to purchase wearable tech. The YouGov study reports data on types of devices consumers are likely to buy, the brands they consider, and where they seek advice on wearable purchases.

Getting to the heart of the matter, however, health is the most common consumer motivation and interest. Asked to choose from a list of 15 features that would be important to them in a wearable device, the highest ranking choice (56 percent) was for tracking heart rate. More than half of those surveyed also chose tracking daily fitness measures (54 percent) and checking the time and date (51 percent). Other popular choices included tracking sleep (44 percent), email and message notifications (37 percent), integrated GPS (35 percent). Fewer than one out of three wanted a device for making and receiving calls.

It may be that citing health-related features for wearable purchase is a rationalization to justify an emotional decision. From a market assessment perspective, however, whether consumers actually need and will use wearables for health purposes or just say that’s why they want to buy a wearable so they’ll feel better about it doesn’t matter in early market stages. The takeaway from the YouGov study is consumers are most interested in features that promote, support, or provide information about health.