Anaerobic threshold

The spectrometer is also used to identify a patient s so-called anaerobic threshold, the point at which the oxygen supply to cells can no longer keep up with demands. A runner, for example, has a certain speed at which he or she can maintain a steady pace for long periods. Any significant pickup in momentum will usually lead to rapid fatigue... 

The anaerobic threshold is the point during strenuous exercise at which anaerobic metabolism and lactic acid production begin." Carbon dioxide production (Vc02,max) increases with exercise at about the same rate as VO2, until the subject s anaerobic threshold is reached. From that point on, VCO2 increases faster than VO2, and this change can be used to estimate the anaerobic threshold. A breath-by-breath plot of the ventilatory equivalents for O2 and CO2 also can be used to determine the anaerobic threshold. Anaerobic threshold is a measure of fitness in normal subjects, and aerobic training can delay the anaerobic threshold. T ... 

PATH-CHF (8) 2002 41 Dilated Cardiomyopathy NYHA III or IV QRS >120 PR >150 NSR Single blind, crossover comparison of optimized univentricular (LV only) versus biventricular pacing No difference between LV only and biventricular pacing in V02max 02 uptake at anaerobic threshold or 6MHWD. All parameters improved significantly versus baseline after 12 months. 

PATH-CHF II (12) 2003 69 LVEF <30% NYHA II-IV V02max <18 QRS>120 XT CO Single blind, crossover, stratified by baseline QRS Significant improvements in V V02max V02 at anaerobic threshold, and 6MHWD after 3 months... 

The lactate produced in the working muscle passes into the blood. Eventually, if strenuous exercise is continued, the concentration of lactate becomes so high that this fermentation can no longer continue. Glycolysis, and thus ATP production, stops. The muscle, deprived of energy, can no longer function. This point of exhaustion is called the anaerobic threshold. 

Both respiration rate and tidal volume (the amount of air moved per breath) increase with exercise, but above the anaerobic threshold the tidal volume no longer increases (remains at about 2 to 2.51). From that point, increases in ventilation require greater increases in respiration rate. A similar limitation occurs for stroke volume in the heart (limited to about 120 ml). 

Anaerobic threshold The transition between exercise levels that can be sustained through nearly complete aerobic metabolism and those that rely on at least partially anaerobic metaboHsm. Above the... 

During starvation, body fats replace dietary carbohydrates as a major source of energy. Metabolism of these fats yields organic acids such as acetoacetic acid. This causes a mild metabolic acidosis. In strenuous exercise, particularly in a trained athlete, fats are preferentially metabolized also, in exercise sufliciently strenuous to exceed the anaerobic threshold, lactic acid is released into the extracellular fluid in all subjects, both the trained athlete and the normal person. Fever and trauma such as extensive bums or major surgery result in tissue breakdown this catabolism results in the release of organic acids into the extracellular fluid. 

Maillefert (56) Maximum tolerated up to 60 mA 10 Hz (200 msec), duty cycle 20 sec on, 20 sec off Biphasic 1 hr each limb 5 days/wk for 5 wk Increased muscle volume Increased walk distance Increased V02max Increased anaerobic threshold Improved NYHA functional class... 

Contrary to studies that reported improvement in ventilatory indicators, Raastad et al. °" showed that the effect of co-3 fatty acids supplementation on cardiac output and peripheral blood flow on increasing aerobic performance did not show positive results. Well-trained soccer players supplemented with 5.2 g/day of fish oil (1.60 g/day EPA and 1.04 g/day DHA) for 10 weeks did not demonstrate an improvement in maximal aerobic power, anaerobic threshold, and running performance. However, supplemented subjects had significantly reduced plasma triglycerides and elevated plasma concentrations of EPA and DHA. 

Raastad, T, Hostmark, A.T., and Stromme, S.B., Omega-3 fatty acids supplementation does not improve maximal aerobic power, anaerobic threshold and running performance in well trained soccer players, Scand. J. Med. Sci. Sports, 1, 25-31, 1997. 

Wyss., V., Ganzit, G.R, and Rienzi, A., Effects of L-carnitine administration on VOj max and the aerobic-anaerobic threshold in noimoxia and acute hypoxia. Eur. J. Appl. Physiol. Occup. Physiol, 60, 1, 1990. 

Schubert, R., Schwoebel, H., Mau-Moeller, A. et al. (2012) Metabolic monitoring and assessment of anaerobic threshold by means of breath biomarkers. Metabolomics 8,1069. 

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