title: Aggravation of exercise performance in patients with anemia by 3% carboxyhemoglobin.
abstract: To evaluate the effect of breathing 50 ppm carbon monoxide (CO) on exercise capacity in persons with anemia, 10 nonsmoking subjects with chronic anemia (mean hemoglobin 8.9 g%) were studied. No subject had heart or lung disease. By double-blind, randomized, crossover design, duration of fatigue-limited exercise after breathing CO and purified air for 1 hr was compared. Mean carboxyhemoglobin levels increased from 2.14 to 3.38% after breathing CO and decreased from 2.15 to 1.86% after breathing purified air, P less than 0.004. Mean exercise duration decreased from 270.8 to 221.0 sec after breathing CO in contrast to an increase from 267.9 to 271.6 sec after breathing purified air, P less than 0.0001. Hence, in the absence of clinical heart or lung disease, increasing carboxyhemoglobin concentrations aggravate exercise performance in nonsmokers with chronic anemia.
mesh_terms: D000368:Aged; D000740:Anemia / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D002248:Carbon Monoxide / Q000494:pharmacology*; D002263:Carboxyhemoglobin / Q000032:analysis; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000187:drug effects*; D011897:Random Allocation; D012146:Rest
chemical_list: D002248:Carbon Monoxide; D002263:Carboxyhemoglobin