You could say something along the lines of:
"Hey, Friend, what's so good about weed? Why are you always smoking it?"
If he's smoking it for medical purposes, then just drop it, but if it's illegal and he's doing it to "look cool", then I would further ask questions about it.
After a workout, your body needs time to rest and repair itself from the previous workout. According to the Mayo Clinic, running too far too often, lifting too much weight or simply pushing yourself too far can lead to muscle strains and sprains, shin splints, and stress fractures.
True Because if you think about it , it makes total sense