['To examine the effects of acute exposure to carbon monoxide and hypoxia on plasma lipids, lipoproteins, and apolipoproteins.', 'Random-order assignment to blinded, inhaled exposures of carbon monoxide and hypoxia.', 'Research laboratory of ambulatory subjects.', '10 elderly, male nonsmokers with chronic stable angina.', 'Random-order two-hour inhaled exposure to clean air at sea level, carbon monoxide at sea level, carbon monoxide at high altitude, and clean air at high altitude.', 'Fasting plasma lipids, lipoproteins, and apolipoproteins before and after exposures.', 'No differences were noted between fasting plasma lipid, lipoprotein, or apolipoprotein levels before and after exposures.'] Does acute exposure to carbon monoxide affect plasma lipids , lipoproteins , and apolipoproteins?