The default
A new account shares nothing. Your visibility settings decide what each audience sees, item by item, and an audience you have not opted into sees nothing at all.
What a peer sees
A peer who can see your progress sees your band and the things you chose to share. They never see the sleep or heart figures the band was built from.
What an employer sees
An employer sponsor sees group figures only, and never one member. A group too small to be anonymous is withheld rather than shown.
Changing your mind
Every sharing choice is reversible from Settings, then Privacy, and takes effect immediately.