If you carry around an iPhone and wear an Apple Watch, those devices are probably already absorbing information about your motion and health. Both devices can track your steps. The Watch measures your pulse, and—if it’s a Series 4 or later—it can even take an ECG or look out for a fall. Plus, these products are obviously input devices—women can use their phone or watch to keep track of data related to their menstrual cycles, for example.

With the release of a new app, Apple hopes to collect health information to conduct research and possibly develop new products. The company hopes to gather info from hundreds of thousands of people—and you can be one of them, if you consent. Here’s what to know about the new Research app out of Cupertino, which is available as of today for people in the United States.

The app is a hub for three new studies: one focused on women’s health, one on noise and hearing, and another on heart health and movement. In brief, the women’s health study will collect data that participants enter regarding their menstrual cycles, plus gather movement and heart information, and ultimately look for any connections between data like that and afflictions such as osteoporosis. The hearing study will explore the relationship between the noise around you, or songs piping in through your AirPods, and how well your ears are doing. And unsurprisingly, the heart and movement study will examine cardiac and motion metrics. Apple might be able to tease out connections—perhaps someone’s pace slows over time, and then they notice that they fell; those two phenomena could be related.

So what’s Apple incentive? In addition to possibly helping improve public health and contributing to the research community (they’ve partnered with organizations like the NIH and the American Heart Association), it wants to make better products that you, naturally, may want to purchase.

To get a sense of the process, I signed up for the hearing study. Apple, which has partnered with the University of Michigan’s School of Public Health for this initiative, states that the study will consider information like sounds I’m exposed to through my headphones or environment, and will ultimately see if that affects my hearing or even my heart health. It also says it will aid the company to “develop new products.” In other words, they’re being clear that perhaps someday the latest generation of AirPods will be engineered in part using data they collect.

It also says that they hope some 150,000 people like me will participate. After providing information like my phone number and email address, I signed a consent form. I also gave my Apple Watch permission to monitor the noise levels around me. Finally, I took a survey that asked questions such as how important music is to me, how many pairs of headphones I use, how good I think my hearing is, and much more. If you love taking surveys, this app is for you. (I didn’t get to the point yet where I got to take a hearing test.)

Apple is targeting a huge number of people—the heart and movement study could include as many as half a million subjects, according to the app, and for the women’s health study, they’re aiming for 500,000 at a minimum.

Of course, this isn’t Apple’s first foray into research. They previously launched ResearchKit, which allowed developers to create research apps, and the company also already completed a 419,297-person study focused on heart health, the results of which were published today in The New England Journal of Medicine.

If you’re interested in participating in these three new studies, download the Research app from the app store. If you’re not, don’t.