Increased hepatic gluconeogenesis: the secret of Lance Armstrong's success.
Enormous amounts of lactic acid are produced during endurance sport by muscle cells. This metabolite is thought responsible for the muscle pain and the fatigue during sport. Its internal removal from the body by enzymatic conversion depends mainly on the capacity of the hepatic gluconeogenesis that converts lactic acid to glucose. The extraordinary sportive results of the racing cyclist Lance Armstrong did us realize that a high capacity of hepatic gluconeogenesis was the basis of his success, because it might have provided him with less pain complaints caused by lactic acid and with an extra source of energy from lactic acid. This enhanced gluconeogenesis can be due to his heavy training program. At the age of 12-13 years he daily swam 10,000m and cycled 32km. In later years as cyclist his training labour was also more than normal. A constitutional increased gluconeogenesis cannot be excluded, because as a boy of 12 years he became already fourth in 1500m free style swimming in a contest for swimmers from whole Texas. The last argument for an increased gluconeogenesis is that Armstrong in October 1996 suffered from an extensively disseminated testicular tumour. This large tumour load caused that in the tumour the oxidative (=aerobic) energy generation changed into a fermentative (=anaerobic) one. This resulted in a high increase of lactic acid that putted up the gluconeogenesis in the liver. We think that this stimulated, high level gluconeogenesis remained high in the following years, when Armstrong restarted cycling, that it provided him with extra energy from lactic acid and with fewer complaints due to the exercise, and that thus this was the basis of his success.
Bongaerts
Ger P A
GP
Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands. G.Bongaerts@mmb.umcn.nl
Wagener
D J Theo
DJ
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology*; D005943:Gluconeogenesis / Q000502:physiology*; D006801:Humans; D008099:Liver / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D017288:Pain Threshold / Q000502:physiology*