As of this morning, iOS users can officially download Apple’s new Research app and sign up for one or more of the three studies the company announced at its WWDC event in September.

Inspired by the Apple Heart Study conducted last year in conjunction with Stanford, these three studies, focused respectively on heart health and movement, hearing loss, and women’s health, are being conducted with prestigious partners. Like the Heart Study, this research has dual goals: it will serve to improve public health, gathering data on an unprecedented scale, and it will help Apple to improve its products.

While the Apple Heart Study took about a year to complete, these three new studies are on longer — in some cases much longer — timetables. The shortest, the hearing study, will run for two years, while the longest, the women’s health study, will run for a decade, maybe more.

All the studies have been submitted to and approved by institutional review boards, and the app includes an informed consent form for each study. California residents will also see an additional document because of the state’s more stringent privacy laws. Finally, one of the three studies (the Heart and Movement study) is being conducted in conjunction with a hospital, so it includes a HIPAA authorization form.

In addition to filling out consent forms, users setting themselves up in the app will also have the opportunity to opt in to each kind of data the app wants to collect, giving them full control about what data is shared with the study team.

For each study, certain data is mandatory; if the user tries to opt out of sharing that data, they’ll be prompted to either change their mind or to exit out of the app and decline to enroll.

After that, apps will collect data through a combination of passive sensing and active tests, depending on the study. Read on for the fast facts on the three studies launching this morning.

The Apple Women’s Health Study

WHAT: Apple has come a long way since its glaring omission of period tracking from the first generation of the Apple HealthKit app. In this 10+ year study, participants will track their menstrual cycles (using Apple’s app or a third-party app) along with other health data and participate in monthly surveys. Researchers hope to uncover connections between menstruation and conditions including polycystic ovary syndrome (PCOS), infertility, osteoporosis and menopausal transition.

WHO: Apple is partnering with Harvard T.H. Chan School of Public Health and the NIH’s National Institute of Environmental Health Sciences (NIEHS) to conduct this study. Over the full course of the study, Apple hopes to enroll a million women.

ON THE RECORD: “Women make up half of the world’s population, yet even today there has been limited investment in studying their unique health needs,” Michelle A. Williams, a reproductive epidemiologist and dean of the faculty at the Harvard T.H. Chan School, said in a statement. “This study, unprecedented in scope, will greatly advance our understanding of the biological and social determinants of women’s health, and lead to better health outcomes.”

The Apple Heart and Movement Study

WHAT: The most direct follow-up to Apple’s 400,000-person Heart Study conducted with Stanford, this study will look at heart rate and rhythm data collected via a user’s Apple Watch, alongside movement and workout data collected on the Watch and phone. Researchers will study how factors that affect heart health are related to deterioration in mobility or overall health, with the ultimate goal of developing more and better preventative tools.

WHO: Apple has tapped the American Heart Association and Brigham and Women’s Hospital as partners on this study. Their goal is to enroll 500,000 participants over five years.

ON THE RECORD: “We are excited to be working with all the study participants and with Apple to identify the features of complex human physiology that lead to different outcomes in wellness or chronic disease, and to use this information to empower individuals to maximize their own health,” Calum MacRae, vice chair of Scientific Innovation for the Department of Medicine at Brigham and Women’s Hospital, said in a statement earlier this year.

The Apple Hearing Study

WHAT: Apple will collect some interesting data for this study on the affects of long-term sound exposure. It will log passive data about how often participants use their headphones and at what volume, and it will use the new Noise app on the Apple Watch to collect environmental sound data. Researchers hope to study the effects of these factors on stress levels and cardiovascular health.

This study has a randomized design: Half of the participants will receive notifications when loud sound exposure is detected, to study whether this is an effective motivator to change behavior.

WHO: Apple’s partner on this project is the University of Michigan. In addition, data will be shared with the World Health Organization’s Make Listening Safe Initiative.

ON THE RECORD: “With over a billion young people who could be at risk of hearing loss due to unsafe listening, WHO is addressing this challenge through raising awareness and setting new standards for safe listening,” Dr. Shelly Chadha, technical officer of prevention of deafness and hearing loss at WHO, said in a statement earlier this year. “The knowledge gained through this study will contribute to future public health action in this field.”