Just that really. He doesn't seem to understand what "one form of exercise a day" means. Yesterday he went to the shops (about a mile round trip, he walked), took DC on a walk and then decided to go on a bike ride! I can understand the first 2, we need to eat and DC need to exercise, but a bike ride after 2 walks is just taking the piss right? On top of that, I'm an NHS worker and am treating coronavirus patients daily, so he's more likely to pass it on than most people. I tried telling him, but he apparently "needs" a daily bike ride 
(it's not like DC are going out every day either, they prefer to exercise in the garden so he can go on a bike ride then). Anyone know how to explain this to a stubborn middle aged man?