Health is a way of pacing Duolingo lessons to discourage binging behavior, which is shown to be ineffective for learning a new language (consider users who don’t care how many mistakes they make but simply progress through lessons to achieve status). You lose Health by answering incorrectly too many times, which has been encouraging users to pay closer attention to what they are answering before hitting “submit”.
Why do we have Health?
Because it’s better for learning. Our research shows that if people advance too quickly on Duolingo in one day, it can actually negatively impact their learning because they are less likely to remember what they’ve learned. We know that users learn best when they study every day and take the time to practice and review what they’ve learned. The Health feature encourages users who are making mistakes to take a breather and review previous lessons before moving forward.
What about other platforms?
Health and Gems are only available on iOS for now. We will be testing these mechanics on Android in the future. We do not currently have plans to bring this to Web.