Blood ammonia concentration after supramaximal treadmill running in males and females.

The purpose of this study was to investigate the difference in human blood ammonia content between the sexes and the relationship between work.lean body mass (LBM)-1 and the peak blood ammonia content following supramaximal exercise. Eight males and six females ran on a motor-driven treadmill reaching exhaustion induced in less than 70 s. Total work, heart rate (HR), blood lactate and ammonia concentrations were measured at rest, immediately after warming-up, and at 2.5, 5, 7.5, 10, 12.5, 15 min after supramaximal exercise. Total work and work.LBM-1 were significantly greater in males than in females (p < 0.01). There was a significant relationship between the peak blood ammonia content and work.LBM-1 in all of the subjects (r, 0.627: p < 0.05). Though no significant difference was found in ammonia at rest between males and females, the peak blood ammonia content after supramaximal exercise in males was significantly greater than in females (p < 0.05). These results suggest that the peak blood ammonia content relates positively to anaerobic work capacity following supramaximal exercise, and that a difference in blood ammonia content exists between the sexes.