"Anaerobic threshold": problems of determination and validation

Abstract

Despite the popularity of the concept of "anaerobic threshold" (AT), the noninvasive detection criteria remain subjective, and invasive validations of AT have been based on lactate data of arterial, mixed venous, venous, and capillary blood samples without any concern for the possible lactate differences from these sources. Eight normal subjects underwent two exercise tests on a bicycle ergometer. The protocol consisted of 3 min of rest, 3 min of 0 work load, and a 20 W/min ramp (1 W/3 s) until exhaustion. Simultaneous arterial and venous blood samples were drawn during the second test. Noninvasive gas response data were measured using a computerized breath-by-breath stress test system. Threshold phenomenon of the lactate accumulation was not found. The arterial lactate levels increased continuously after the start of the exercise ramp. The rise in venous lactate lagged behind the rise of the arterial lactate by about 1.5 min, and therefore venous lactate was not considered suitable for AT detection. Four independent exercise physiologists determined AT from the gas response data. The reviewer variability (avg range 16%) of AT for a given subject was representative of AT values reported for untrained and trained individuals (40-70% maximum O2 consumption). We concluded that 1) AT is not detectable using invasive methods (arterial and venous lactates); and 2) the noninvasive gas response determination has such a large range of reviewer variability that it is unsuitable for clinical use.

Cardiopulmonary exercise testing as a risk assessment method in non cardio‐pulmonary surgery: a systematic review

“…Whether lactate appears suddenly or if there is gradual accumulation over a period of time is debated [16][17][18][19][20][21]. If this former hypothesis were correct it would make the VAT less relevant (in contrast to LAT) in providing an accurate indication of the onset of anaerobic respiration.…”

“…The work rate at which AT occurs can then be derived (arrow). are several methods, using measures of physiological responses to lactate production, which can be employed to non-invasively estimate the transition from predominantly aerobic metabolism to predominantly anaerobic metabolism during exercise.Whether lactate appears suddenly or if there is gradual accumulation over a period of time is debated [16][17][18][19][20][21]. If this former hypothesis were correct it would make the VAT less relevant (in contrast to LAT) in providing an accurate indication of the onset of anaerobic respiration.…”

Maximal and submaximal oxygen uptake efficiency slope: influence of cardiorespiratory variables and maximal dynamic strength

“…In turn, RE is defined as the oxygen consumption demanded for a given running speed [7]. While these cardiorespiratory parameters are closely associated with aerobic fitness, the detection of the VT and the RCP may be biased by several factors including the different methods of detection and the experience of the evaluators [8][9][10]. On the other hand, the RE measurement demands at least an additional experimental session, mainly when two or more speeds will be tested or when the individual has a low fitness level.…”

Reproducibility of lactate markers during 4 and 8min stage incremental running: A pilot study

“…4 Furthermore, lactate clearance rate appears limited at workloads approaching LT. 5 Lactate response is influenced by the blood sampling site, 6 in particular, venous blood has been seen to overestimate workload during short stage increments. 7 To characterise a curvilinear blood lactate response, various endurance markers and single summary statistics have been proposed.…”