Physiological responses to cycling for 60 minutes at maximal lactate steady state.

Changes in physiological variables during a 60-min continuous test at maximal lactate steady state (MLSS) were studied using highly conditioned cyclists (1 female and 9 males, aged 28.3 +/- 8.1 years). To determine power at MLSS, we tested at 8-min increments and interpolated the power corresponding to a blood lactate value of 4 mmol/L. During the subsequent 60-min exercise at MLSS, we observed a sequential increase of physiological parameters, in contrast to stable blood lactate. Heart rate drifted upward from beginning to end of exercise. This became statistically significant after 30 min. From 10-60 min of exercise, a change of +12.6 +/- 3.2 bpm was noted. Significant drift was seen after 30 min for the respiratory exchange ratio, after 40 min for the rate of perceived exertion using the Borg scale, and after 50 min for % VO(2)max/kg and minute ventilation. This slow component of VO(2)max may be the result of higher recruitment of type II fibers.

[1]  C. Reggiani,et al.  Sarcomeric Myosin Isoforms: Fine Tuning of a Molecular Motor. , 2000, News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society.

[2]  R. Woledge,et al.  Possible effects of fatigue on muscle efficiency. , 1998, Acta physiologica Scandinavica.

[3]  T. Barstow,et al.  Effect of increased muscle temperature on oxygen uptake kinetics during exercise. , 1997, Journal of applied physiology.

[4]  T. Swensen,et al.  Noninvasive estimation of the maximal lactate steady state in trained cyclists. , 1997, Medicine and science in sports and exercise.

[5]  R. Beneke,et al.  Maximal lactate steady state during the second decade of age. , 1996, Medicine and science in sports and exercise.

[6]  R. Casaburi,et al.  Influence of muscle fiber type and pedal frequency on oxygen uptake kinetics of heavy exercise. , 1996, Journal of applied physiology.

[7]  L V Billat,et al.  Use of Blood Lactate Measurements for Prediction of Exercise Performance and for Control of Training , 1996, Sports medicine.

[8]  B. Sjödin,et al.  Comparison of Blood Lactate Concentrations Obtained During Incremental and Constant Intensity Exercise , 1996, International journal of sports medicine.

[9]  S. V. von Duvillard,et al.  Determination of maximal lactate steady state response in selected sports events. , 1996, Medicine and science in sports and exercise.

[10]  D. Poole,et al.  The Slow Component of Oxygen Uptake Kinetics in Humans , 1996, Exercise and sport sciences reviews.

[11]  W. Willis,et al.  Mitochondrial function during heavy exercise. , 1994, Medicine and science in sports and exercise.

[12]  B. Sjödin,et al.  The validity and accuracy of blood lactate measurements for prediction of maximal endurance running capacity. Dependency of analyzed blood media in combination with different designs of the exercise test. , 1994, International journal of sports medicine.

[13]  A. Snyder,et al.  A Simplified Approach to Estimating the Maximal Lactate Steady State , 1993, International journal of sports medicine.

[14]  B Coen,et al.  Individual anaerobic threshold and maximum lactate steady state. , 1993, International journal of sports medicine.

[15]  T R Brown,et al.  Regulation of oxygen consumption in fast- and slow-twitch muscle. , 1992, The American journal of physiology.

[16]  T M McLellan,et al.  A comparative evaluation of the individual anaerobic threshold and the critical power. , 1992, Medicine and science in sports and exercise.

[17]  J D Veldhuis,et al.  Exercise Training at and above the Lactate Threshold in Previously Untrained Women , 1992, International journal of sports medicine.

[18]  W. Byrnes,et al.  A comparison of the oxygen drift in downhill vs. level running. , 1992, Journal of applied physiology.

[19]  W Schaffartzik,et al.  Contribution of exercising legs to the slow component of oxygen uptake kinetics in humans. , 1991, Journal of applied physiology.

[20]  E. Coyle,et al.  Fluid replacement and glucose infusion during exercise prevent cardiovascular drift. , 1991, Journal of applied physiology.

[21]  I. Jacobs,et al.  Incremental Test Protocol, Recovery Mode and the Individual Anaerobic Threshold , 1991, International journal of sports medicine.

[22]  Jan Svedenhag,et al.  Applied Physiology of Marathon Running , 1985, Sports medicine.

[23]  G. Heigenhauser,et al.  Effect of glycogen depletion on the ventilatory response to exercise. , 1983, Journal of applied physiology: respiratory, environmental and exercise physiology.

[24]  W. Kindermann,et al.  Comparison of Prolonged Exercise Tests at the Individual Anaerobic Threshold and the Fixed Anaerobic Threshold of 4 mmol·l-1 Lactate* , 1982, International journal of sports medicine.

[25]  W. Kindermann,et al.  Lactate Kinetics and Individual Anaerobic Threshold* , 1981, International journal of sports medicine.

[26]  N. Jones,et al.  Metabolism of infused L(+)-lactate during exercise. , 1979, Clinical science.

[27]  A. Chassain Méthode d'appréciation objective de la tolérance de l'organisme à l'effort: application à la mesure des puissances critiques de la fréquence cardiaque et de la lactatémie , 1986 .

[28]  A S Jackson,et al.  Prediction accuracy of body density, lean body weight, and total body volume equations. , 1977, Medicine and science in sports.

[29]  L G Ekelund,et al.  Circulatory and respiratory adaptation during prolonged exercise. , 1967, Acta physiologica Scandinavica. Supplementum.