FIG. 8:  Thinking “outside the box” about how pulmonary rehabilitation works, a good analogy is that of the bumblebee.^[9]  According to conventional aerodynamic principles, the bumblebee should not be able to fly, because its diminutive wings are too small for its large body.  It is only after thinking “outside the box” and realizing that the bumblebee flies more as a helicopter than an airplane that it all makes sense.  One of the realities of pulmonary rehabilitation is that it does not affect the forced expiratory volume (FEV₁) of respiration; so how does pulmonary rehabilitation work?