title: Blood ammonia and lactate concentrations during endurance exercise of differing intensities.
abstract: The purpose of this study was to examine the changes of blood ammonia concentration ([NH3]b) during endurance exercise of differing intensities on the cycle ergometer and to compare [NH3]b to the changes observed in the simultaneously monitored blood lactate acid concentrations ([la-]b) measurements. A group of 16 endurance-trained athletes participated in the first part of the study and performed exercise of 30 min duration in a randomized order at intensities of 85%, 95%, 100% and 105% of their individual anaerobic threshold (Th(an,ind); E85-E105) which had been determined beforehand by a cycle exercise test with stepwise increments in intensity. In the second part, 18 average endurance-trained sports students underwent exhausting intensive endurance exercise (IEE) with an intensity of 95% of Th(an,ind). An extensive endurance exercise (EEE) of the same duration at 85% of the Th(an,ind) was carried out 2 days later. The [NH3]b increased constantly with increasingly duration of all exercise. However, [la-]b only increased during exercise with intensities above the Th(an,ind) (E105). The increase of [NH3]b was higher with higher exercise intensities. At IEE, [NH3]b was significantly higher from the 30th min than at EEE, whereas [la-]b increased from the 5th min. In conclusion, [la-]b responded more sensitively to the intensity of exercise than [NH3]b, but it is conceivable that in the future measurements of [NH3]b could be used to advise on the duration of endurance training. At present, however, the lack of experience and lack of appropriate values still hinders the systematic use of [NH3]b measurements in the physiological monitoring of sports training.
authors.affiliation: Institute of Sports and Performance Medicine, University of the Saarland, Saarbrücken, Federal Republic of Germany.
authors.forename: A
authors.initials: A
authors.lastname: Urhausen
authors.forename: W
authors.initials: W
authors.lastname: Kindermann
mesh_terms: D000328:Adult; D000641:Ammonia / Q000097:blood*; D000693:Anaerobiosis / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D007773:Lactates / Q000097:blood*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*
chemical_list: D007773:Lactates; D000641:Ammonia