Hearts in android - thumbs down.
The hearts feature in the android app are not a good update for the way and reasons i am using duolingo. I dislike the weekly contests and stopped paying attention to them. But now the hearts show up and i am not happy with this update. I am seriously studying for my ccna and the hearts just make this take too much time away from that now. I want a quick 15 min change of pace from the serious studying i am currently doing. I have a 160 day streak that with out a doubt fall. At least i am dropping down to the minimum number of points per day if i don't leave duolingo altogether.
Perhaps you mean Health?
Hearts is the old game mechanic from ages ago. Though you still see Hearts when testing-out or taking a tree short-cut.
Health is the new system, where you lose a bar of Health with each error. When you have lost all five bars, you cannot start any new lessons. You are supposed to strengthen instead (or take a break).
If you are doing 15 minutes, then Health shouldn't be too much of an obstacle. Just do some strengthening, if you have no bars remaining. If you do the strengthening from the Health menu, then you should earn some Health back.
You must be in an A/B test; I don't have it on mine (then again, I think I'm in an A/B for the new achievement pictures, and man are they ugly...).
Would using the web site via a mobile browser (not the app) be an option? Might be a little less comfortable, but no health feature, I'd imagine.
By the way, good luck on your test! I've heard Cisco exams are...........interesting. But I'm sure you can do it! :)