How do I turn off pre-workout activity sharing pop-ups on my Apple Watch?

Every time I start a new workout from my watch, I get two annoying interstitial screens asking if I want to share fitness activities with my friends. I currently do not, and if I did, I would not want to be prompted at the start of EVERY workout to send them a notification about it. How to I turn off these pre-workout pop-ups on my watch?