Diastra

Diastra reads every workout your Apple Watch saved in Apple Health. It finds your max heart rate from your own runs, a guided test or a number you type, and it says which one it used.

From that max, it draws three bands called Easy, Threshold and VO₂max. Easy is the Zone 2 runners know, and its top edge is split by sex.

Diastra builds a weekly plan that rebuilds around what really happened. On the watch, a tap tells you when you drift out of your band.

Over the weeks, you see whether your training is working. It works without an account.