I'm not sure what smoking can do to your nage, but I know what it can do to your uke.
Smoking causes a host of tissue issues in the circulatory system, as well as the muscular system. It lowers red blood cell production, your macrophages lower, and increases micro-vascular occlusion and tissue ischemia. Platelets in the tissues can also become hyper-adhesive, and inflexible. (most of these issues are caused by increase of carbon in the system, so weed is in trouble too here.
All in all, if you take a bad fall on your shoulder, or get twisted up on a projection, it will take a smoker almost 4times longer to heal those injuries. A statistic that grows after the age of 30 dramatically.
Indeed! It's like I've told my friends: look in your bong; you're coating your lungs and cardiovascular system with the same stuff. Combine the information you provided with the Chinese Medicine perspective expressed a short while back and it seems pretty clear to me that the somewhat subtle nature of some of the effects are cause enough for serious caution, let alone with the very obvious effects on the lungs.