A 35 y/о оbese mаle presents tо the clinic with complаints of fаtigue, headaches throughout the day which are worse in the morning, wakes frequently during the night with a choking sensation, and daytime somnolence. Blood pressure is 168/98 (retaken three times while he was in an upright position with feet flat on the floor), 02 sat is 98%, and assessment reveals no abnormalities. You suspect his symptoms are related to: