Disease relevance of Anaerobic Threshold

• During exercise, the level of oxygen consumption (VO2) above which aerobic energy production is supplemented by anaerobic mechanisms causing a sustained increase in lactate and metabolic acidosis is termed the anaerobic threshold [1].
• Among the 21 patients without previous myocardial infarction, the 12 with a low ischemic threshold, which occurred during the first three steps of the modified Bruce protocol, had an anaerobic threshold significantly lower than the other nine patients (13.1 +/- 1.5 versus 14.9 +/- 1.0 ml/kg per minute VO2, p less than 0.01) [2].
• Neither the symptom chest pain nor the degree of ST-depression showed a significant influence on the physical performance capacity and the lactate concentration at the anaerobic threshold [3].
• Effects of verapamil on the anaerobic threshold and peak oxygen consumption in effort angina pectoris [4].
• Recent studies have suggested beneficial effects of training in subjects with moderate or even severe left ventricular dysfunction by showing increased exercise tolerance or peak O2 consumption, anaerobic threshold, peak leg blood flow, peak central arteriovenous oxygen difference and decreased lactate accumulation [5].

High impact information on Anaerobic Threshold

• There were significant rises in exercise time (mean [SD] 13.2 [5.5] to 20.0 [6.2] min), maximum oxygen consumption (19.1 [7.0] to 25.0 [6.7] ml.min-1.kg-1), and anaerobic threshold (11.7 [3.6] to 15.4 [4.8] ml.min-1.kg-1) after 2 months of erythropoietin treatment [6].
• The thallium distribution in these muscles at peak exercise was the same as at the anaerobic threshold [7].
• There were no significant differences between the placebo and enalapril subgroups at any time with regard to peak VO2, exercise duration, or the VO2 at the anaerobic threshold [8].
• The anaerobic threshold in chronic heart failure. Relation to blood lactate, ventilatory basis, reproducibility, and response to exercise training [9].
• Thus, the anaerobic threshold can be considered to be an important assessment of the ability of the cardiovascular system to supply O2 at a rate adequate to prevent muscle anaerobiosis during exercise testing [10].

Chemical compound and disease context of Anaerobic Threshold

• These findings are consistent with the concept that the metabolic acidosis threshold is synonymous with an anaerobic threshold, i.e., the latter demarcating the VO2 above which the contracting muscles are not adequately supplied with O2 but below which they are [11].

Biological context of Anaerobic Threshold

• RESULTS: With a mean follow-up of 25+/-10 months, ejection fraction, heart rate, systolic arterial pressure, peak VO(2), VCO(2), the anaerobic threshold, minute ventilation, the ventilatory equivalents of oxygen and carbon dioxide, the half times of VO(2) and VCO(2) recoveries, and the circulatory stroke work and power predicted outcome [12].
• A simple test is described for identifying patients with abnormalities of muscle energy metabolism secondary to mitochondrial dysfunction, based on the venous lactate response to exercise at 90% of predicted work rate at the anaerobic threshold [13].
• VO2/t-slope correlated with the VO2 peak (r = 0.84, P<0.001), anaerobic threshold (r = 0.79, P<0.001), and T(1/2)VO2, a previously established estimate of recovery O2 kinetics (r = -0.59, P<0.001) [14].
• Factors (expired ventilatory volume, respiratory frequency, tidal volume, end-tidal CO2 tension, and heart rate) that may have affected RPE, maximal aerobic power, and anaerobic threshold (AT) were also statistically unchanged because of cycle day [15].
• Heart rate (HR), blood pressure (BP), oxygen uptake (VO2), minute ventilation (VE), and carbon dioxide production (VCO2) were evaluated at rest, 3.0 mph/0% grade, the gas exchange anaerobic threshold (ATge), 80% of placebo maximal O2 uptake, and maximal exercise [16].

Anatomical context of Anaerobic Threshold

• In 17 naive subjects, carotid body O2 chemosensitivity was tested repeatedly during exercise above the ventilatory anaerobic threshold (VAT) using 2 breaths of O2 [17].
• Ventilation is abnormal before anaerobic threshold, and predicts subsequent lactate rise, suggesting that skeletal muscle is the origin of excessive ventilation [18].
• The study was conducted for 10 weeks with pre and post values obtained for cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, maximal oxygen consumption (VO2max), ventilatory anaerobic threshold (VAT), percent body fat, and dietary composition of macronutrients and polyunsaturated to saturated fat (P:S) ratio [19].

Associations of Anaerobic Threshold with chemical compounds

• To estimate the anaerobic threshold by gas exchange methods, we measure CO2 output (VCO2) as a continuous function of O2 uptake (VO2) (V-slope analysis) as work rate is increased [10].
• But most conveniently, changes in gas exchange caused by the physical-chemical event of buffering of lactic acid by bicarbonate can be used to detect the anaerobic threshold during exercise [1].
• The glycogenolytic action of epinephrine may play an important role in determining peak exercise capacity since glycogen stores are increasingly utilized at work rates above the anaerobic threshold [20].
• Each patient was investigated in rest-recumbent (RR) and rest-sitting (RS) positions and during an uninterrupted, graded, submaximal exercise test (up to the anaerobic threshold) before treatment, and with a similar protocol 75 minutes after treatment with captopril or placebo on the same morning [21].
• The training group showed a significant improvement of aerobic capacity measured by anaerobic threshold VO(2) (14.67 +/- 3.03 versus 17.08 +/- 3.35 ml/kg/minute, P < 0.001) [22].

Gene context of Anaerobic Threshold

• PAI activity decreased during maximal (from 6.6 [2.51] AU/ml to 2.0 [2.00], p < 0.05) and anaerobic threshold (5.0 [2.07] to 0.2 [0.22], p < 0.01) tests but not during aerobic threshold test (7.0 [3.69] to 4.5 [2.93], p = 0.123) [23].
• Inspiratory muscle performance relative to the anaerobic threshold in patients with COPD [24].
• To evaluate the role of heredity in the pituitary responses to exercise-related stress, serum ACTH, beta-endorphin, cortisol, GH, and PRL responses to a thirty-minute treadmill exercise at individual anaerobic threshold were evaluated in nine pairs of male monozygotic twin athletes [25].
• The anaerobic threshold during graded exercise (GXT, AT1) was determined as the exercise level initiating a curvilinear increase in ventilation (VE), and during prolonged exercise (PXT, 40 min, AT2) as the maximal exercise level where still a steady state for VE can be reached [26].
• Power outputs that are below the anaerobic threshold (theta an) may be sustained for prolonged durations, whereas power outputs that are greater than theta an result in a significant reduction in the tolerable duration to fatigue [27].

Analytical, diagnostic and therapeutic context of Anaerobic Threshold

• Comparison of the training group and control group after 12 weeks showed a significant difference relating to VO(2max) (24.31 +/- 4.61 versus 21.21 +/- 3.88 ml/kg/minute, P = 0.01) and anaerobic threshold VO(2) (17.08 +/- 3.35 versus 13.66 +/- 2.82 ml/kg/minute, P < 0.0001) [22].
• Doppler echocardiography was used to assess diastolic function in 40 patients with hypertrophic cardiomyopathy and to relate it to the patients' symptoms, anaerobic threshold and maximal oxygen consumption during cardiopulmonary exercise testing [28].
• The 6 (10.2%) patients dying within 100 days of transplantation were more likely to have reduced aerobic capacity (peak VO(2) <60% predicted and VO(2) at anaerobic threshold [VO(2)-AT] <50% predicted peak VO(2)) compared to survivors (4/6 vs. 7/53, P <.01) [29].
• Measurements during bicycle ergometry consisted of O2 uptake at the anaerobic threshold and of maximum O2 uptake [30].
• Noninvasive determinations of the anaerobic threshold. Reliability and validity in patients with COPD [31].

References