title: Lactate release, concentration in blood, and apparent distribution volume after intense bicycling.
abstract: To study the release of lactate from muscle and its relationship to the blood lactate concentration during and after intense bicycling, young men cycled at 5.5 W kg(-1) body mass for 2 min to exhaustion or stopped after 1 min (nonexhaustive ride). The leg's release of lactate during and after each ride was taken from the measured blood flow and lactate concentrations in arterial and femoral-venous blood. Muscle biopsies were taken in separate experiments and analyzed for lactate. During the bicycling, 6 to 10% of the lactate produced was released to the blood. During exercise and for the first few minutes after, the rate of lactate release did not differ between 2 min exhaustive and 1 min nonexhaustive bicycling. The integrated release (exercise plus recovery) for the 1 min bicycling was 60 to 80% of the corresponding value of the 2 min exhaustive bicycling. In the late recovery, the blood lactate concentration was 3 to 5 times higher after 2 min exhaustive bicycling than after the 1 min nonexhaustive bicycling. There was thus a mismatch between the amount of lactate released and measured concentration in blood, reflecting a smaller distribution volume after the exhaustive bicycling. The blood lactate concentration may therefore not be a good measure of the lactate production and anaerobic energy release during bicycling.
authors.affiliation: National Institute of Occupational Health, N-0033-8149 Oslo, Norway. Jon.Medbo@stami.no
authors.forename: J I
authors.initials: JI
authors.lastname: Medbø
authors.forename: K
authors.initials: K
authors.lastname: Toska
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001706:Biopsy; D015992:Body Mass Index; D006801:Humans; D019344:Lactic Acid / Q000097:blood* / Q000493:pharmacokinetics; D007866:Leg / Q000098:blood supply / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*
chemical_list: D019344:Lactic Acid