Aggravation of exercise performance in patients with anemia by 3% carboxyhemoglobin.

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.

Duke Scholars

Author Michael Hugh Sketch Jr. Medicine, Cardiology