In the finasteride group , the eupneic ventilatory parameters were unchanged ; however , the AT was decreased ( 38.9 0.6 mm Hg vs. 37.7 0.9 mm Hg , P = 0.02 ) and the CO reserve was increased ( -2.5 0.3 mm Hg vs. -3.8 0.5 mm Hg , P = 0.003 ) at follow-up , with a significantly lower hypocapnic ventilatory response , thus indicating increased breathing stability during sleep .