Bibliography: leaves 230-255. The work described in this thesis was stimulated by the observation that during leg exercise, resting forearm lactate kinetics appear to resemble closely the blood-tissue exchange kinetics of inert gases that have been reported in many organs during inert gas inhalation. Two mathematical models of forearm lactate uptake were developed, and three series of experiments were conducted to investigate the contribution and impact of passive (inert-like) lactate movements to veno-arterial concentration differences in the resting forearm during leg exercise. The results are discussed.

Bibliography: leaves 230-255. / xv, 255 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The work described in this thesis was stimulated by the observation that during leg exercise, resting forearm lactate kinetics appear to resemble closely the blood-tissue exchange kinetics of inert gases that have been reported in many organs during inert gas inhalation. Two mathematical models of forearm lactate uptake were developed, and three series of experiments were conducted to investigate the contribution and impact of passive (inert-like) lactate movements to veno-arterial concentration differences in the resting forearm during leg exercise. The results are discussed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physiology, 2000

Thesis (Ph.D.) -- University of Adelaide, Dept. of Physiology, 2000. / Bibliography: leaves 230-255.

Thesis (doctoral)--Ludwig Maximilians-Universität zu München, 1979.

Thesis (doctoral)--Friedrich-Wilhelms-Universität, Bonn, 1903.

It is a well-documented finding that blood lactate concentrations at any given absolute or relative (% of maximum oxygen uptake; % VO₂ₘₐₓ) workload, are lower following endurance training. The search for the mechanisms responsible for lower blood lactate concentrations after training, however, has led to conflicting results, particularly when the possible causes of this finding have been investigated in humans. In this study, three questions related to the effects of endurance training on lactate metabolism were investigated.

Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Medicine, 1998. / During graded exercise, an intensity is reached where a subjects ability to remove lactate lags behind the rate of lactace production. The influence of body fluid shifts, during exercise of increasing intensity, on the pattern of the blood lactate response was studied. The maximal oxygen uptake (V02 max) was measured using a treadmill, on eleven subjects. Subsequently, lactate accumulation in venous blood was measured, in triplicate, up to an oxygen consumption greater than 90% V02max. During all exercise, oxygen consumption was measured using an online system. In addition, the blood samples at each workload were used to determine haematocrit (Hct) and haemoglobin (Hb) levels. The Hct and Hb values were used to calculate lactate accumulation (corrected for body fluid shifts) as opposed to the absolute or total lactate levels. The correction for body fluid shifts was done using two techniques. The one using haematocrit only and the other using both haematocrit and haemoglobin. The total and accumulated lactate levels were related to %V02max using two different models. Firstly, a lactate threshold (LT) was determined using the classic lactate turning point (LTP) concept, (ie. two straight lines fitted to the data points) . These Tines iii were computer generated. The intercept of the two lines (LT) was compared for total lactate against accumulated lactate (calculated using Hct alone and secondly Hct in combination with Hb. In the latter cases, both the LT intercepts were shifted slightly to the right (ie. to a higher % of V02max) . The average difference in LT when adjusting with Hb and Hct was 0,519 of %V02max (0,72% change) and when adjusting with Hct only was 1,17 of %V02 max (1,65% change). Secondly, an exponential curve was fitted by regression to the data (r=0.989+/-0.018). A substantial shift in the curve, both down and to the right, was obtained when adjusting total lactate to accumulated lactate. The %V02 max at a lactate concentration of 4 mmol/I was used to define the position of the curve. The difference when using Hct alone to calculate accumulated lactate corrected for fluid shift was - 9,20% of V02max (p<0.05), and when using Hb and Hct in combination, -8,71% of V02max (p<0,05) . It is concluded that expressing the lactate curve as an accumulated curve (corrected for body fluid shifts), rather than in absolute terms, significantly alters the construction of the curve during the exercise protocol used in this study. This is especially relevant when using the exponential model,

This study examines factors that determine blood lactate accumulation during exercise in order to examine the opposing theories that such accumulation occurs either as a result of muscle anaerobiosis or an "overflow" of oxygen-independent glycolysis.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Graduation date: 1993