ADRB2 and cor pulmonale: While we did not, and were not expecting to observe severe or even moderate exercise induced arterial hypoxemia (SaO2, <88% or 88–93%, respectively) given the present workload intensities coupled with an absence of cardiopulmonary disease, it is still consistent with these data that relative to each group a modest‐to‐moderate pattern of decreased CaO2 occurred for adults demonstrating the Arg16Arg β2AR genotype.