The lungs / chest thing is utter b.s. As is the "as wide as your shoulders" thing. They are both just old traditions with no basis in science or reality.

Wider bars give a bit more feeling of leverage, most noticeable when climbing out of the saddle. A bit noticeable if sprinting in the drops, but that depends also on your sprinting style and form. Wider bars are a bit less aero (more frontal area).

Ride the bars you like best and don't worry.