What's a good Android app for tracking my sleep patterns and heart rate, especially something that's actually reliable during those crazy 12-hour shifts?

Okay, so I've been using Zepp for about six months now, and honestly, it's been a lifesaver. As a nurse, I need something that's actually reliable and doesn't crap out on me mid-shift. Zepp tracks my sleep patterns – which, let's be honest, are a mess – and my heart rate, which is useful for spotting trends. It's like having a pocket reference guide for my own body! The best part? It hasn't crashed once in six months. I'm too tired to learn complicated apps, but this one has a no-fuss approach. I can glance at the data and actually understand what's going on. It helps me make sure I'm getting enough rest (or at least trying to!) and not pushing myself too hard. Seriously, it just works when you need it to, which is more than I can say for some of the other apps I've tried.