Changes in blood ammonia, lactate and amino acids in relation to workload during bicycle ergometer exercise in man.

Whole body exercise at intensities up top 50% VO2max has no effect on the concentration of blood ammonia but a threefold rise in blood ammonia is observed at workloads up to maximal. There is a linear relationship between blood ammonia and lactate production during exercise which suggests that the two processes may be linked to a common process of short-term energy provision. Blood glutamine and blood alanine both show rises linearly related to power output during exercise, suggesting that if these amino acids are sinks for ammonia then the process of ammonia incorporation is saturated at high workloads.