There are things Zepraug does not settle, and that is deliberate.
A health app that asserts everything is an app that invents. On these three subjects, the literature does not allow a target to be set for you: we show you your values, and what is published, as it stands, and we stop there.
Aim for 20% deep sleep
The National Sleep Foundation panel publishes a range (16 to 20% deep sleep, set for adults aged 26 to 64), observed in the laboratory and with weak consensus. The app shows it to you as such from 18 to 64, and shows none before 18 or from 65 on. Never as a target: a watch can see far less deep sleep than the laboratory, 43 minutes less in a study of the Apple Watch Series 8.
Do 80% of your cardio in zone 2
The two reference meta-analyses find no difference between the models for anyone who is not a competitor. The app shows you where you spend your time, without telling you where to spend it.
Past 7,000 steps, keep climbing
Past 7,000, the two meta-analyses diverge: one finds a plateau, the other a benefit that continues to 17,000. Nobody settles it, and neither does the app.
The benchmarks the app does show are all sourced. Our benchmarks and their sources.