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Medicine & Science in Sports & Exercise: November 1994
Symposium: Mechanistic Basis of the Slow Component of JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 Kinetics During Heavy Exercise: PDF Only


This paper: 1) Reviews evidence for the location of the slow component of JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 kinetics either within the exercising limbs or alternatively at some site in the rest of the body, e.g., ventilatory, cardiac or accessory muscles. 2) Presents evidence in support of both the fast and slow components (i.e., <3 min and >3 min from exercise onset, respectively) of the exercise JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 response residing predominantly in the exercising muscle. For a pulmonary JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 slow component in excess of 600 ml O2·min−1, more than 80% could be attributed to an augmented JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 across the exercising limbs. 3) Assesses the potential for the lactate ion per se to exert a metabolic stimulatory effect in exercising muscle in the absence of the potentially confounding influences of changes in muscle temperature, H+, blood flow or O2 delivery. Within the surgically isolated, electrically stimulated canine gastrocnemius, square wave infusions that increased arterial blood [lactate] by ∼10 mM and intramuscular [lactate] to in excess of 9 mM did not increase muscle JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2. In summary, these investigations demonstrate that the exercising muscle is the predominant site of the JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 slow component. However, despite the close temporal association between changes in blood lactate and JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 during intense exercise, lactate itself does not mandate an additional JOURNAL/mespex/04.02/00005768-199411000-00007/ENTITY_OV0312/v/2017-07-20T222430Z/r/image-pngO2 demand in exercising dog muscle.

©1994The American College of Sports Medicine