Blood lactate during constant-load exercise at aerobic and anaerobic thresholds

Abstract

Venous blood lactate concentrations [1ab] were measured every 30 s in five athletes performing prolonged exercise at three constant intensities: the aerobic threshold (Thaer), the anaerobic threshold (Than) and at a work rate (IWR) intermediate between Thaer and Than. Measurements of oxygen consumption (VO2) and heart rate (HR) were made every min. Most of the subjects maintained constant intensity exercise for 45 min at Thaer and IWR, but at Than none could exercise for more than 30 min. Relationships between variations in [1ab] and concomitant changes in VO2 or HR were not statistically significant. Depending on the exercise intensity (Thaer, IWR, or Than) several different patterns of change in [1ab] have been identified. Subjects did not necessarily show the same pattern at comparable exercise intensities. Averaging [1ab] as a function of relative exercise intensity masked spatial and temporal characteristics of individual curves so that a common pattern could not be discerned at any of the three exercise levels studied. The differences among the subjects are better described on individual [1ab] curves when sampling has been made at time intervals sufficiently small to resolve individual characteristics.

Accuracy of neuro-fuzzy logic and regression calculations in determining maximal lactate steady-state power output from incremental tests in humans

“…In addition, previous studies have pointed out that periods longer than 1-5 min are required to reach a steady state of LA (Foxdal et al 1996;Hughson et al 1987;Oyono-Enguelle et al 1990;Stegmann et al 1981;Uhrhausen et al 1993). Measurements based on LA further assert the finding that LA does not reflect the metabolic activity of working muscles as previously described by Na¨veri et al (1997), Jorfeldt et al (1978), Karlsson and Jacobs (1982), and Foster (1995) who compared lactate (La -) concentrations in skeletal muscle to LA of healthy subjects and patients with congestive heart failure.…”

“…The fixed LA threshold (Beneke and von Duvillard 1996;Foxdal et al 1996;Heck et al 1985;Mognoni et al 1990;Oyono-Enguelle et al 1990) 2. The threshold of the LA deflection point (Aunola and Rusko 1992;Haverty et al 1988;Ribeiro et al 1986) 3.…”

Effect of Thiamine Pyrophosphate on Levels of Serum Lactate, Maximum Oxygen Consumption and Heart Rate in Athletes Performing Aerobic Activity

“…The first drop of blood was discarded; the second one was applied to the reactive strip to be immediately read by an Accusport ® analyser (Total Perfomance Inc, Mansfield, USA) at a wavelength of 660 nm. 19 It took 60 s for this instrument to determine the enzymatic and photometric measurements of the capillary blood sample. The analyser's effectiveness has been reported and validated previously.…”

Critical velocity as a predictor of anaerobic threshold in swimming

“…Foi também verificado que a velocidade correspondente ao LAn poderia ser mantida durante 50 minutos ou mais de corrida (Stegemann & Kindermann, 1982). A maior eficiência para o treinamento aeróbio parece ocorrer com intensidade de treinamento correspondente ao LAn, conforme demonstrado em natação (Maglischo, Maglischo, Smith, Bishop & Hovland, 1984), em cicloergômetro (Denis, Dormois, Castells, Bonnefoy, Padilla, Geyssant & Lacour, 1988;Denis, Dormois & Lacour, 1984;Denis et alii, 1982) e em esteira rolante (Pierce, Weltman, Seip & Snead, 1990). Verificou-se também que o LAn apresenta uma especificidade ao tipo de exercício, maior do que para o V02max> sugerindo que o primeiro é um indicador das adaptações musculares periféricas (Pierce et alii, 1990).…”

“…Assume-se, frequentemente que o LAn é demarcado pela maior intensidade de exercício que pode ser realizada sem aumento da concentração sangüínea de lactato, ou seja, o equilíbrio dinâmico máximo do lactato sangüíneo ([Lac]Sssmax) (Oyono-Enguelles, Heitz, Paterson & Smith, 1990).…”