Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests

• Autor(a) principal: Simões, Herbert Gustavo
• Data de Publicação: 1999
• Outros Autores: Campbell, Carmen Silvia Grubert, Kokubun, Eduardo, Denadai, Benedito Sérgio, Baldissera, Vilmar
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UCB
• Texto Completo: http://hdl.handle.net/123456789/156; https://repositorio.ucb.br:9443/jspui/handle/123456789/7354
• topic: Individual anaerobic threshold; Lactate minimum; Individual glucose threshold; Glucose minimum; Aerobic capacity evaluation

The equilibrium point between blood lactate production and removal (Laÿmin) and the individual an- aerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La)]b, catecholamine and cortisol concentra- tions, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc]b, this study investi- gated the [Glc] and [La)]b responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum (Glcmin) in addition to IAT and Laÿ min in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v3km); IAT and IGT ± 8 ´ 800 m runs at velocities between 84% and 102% of v3km; Laÿ min and Glcmin ± after lactic acidosis induced by a 500-m sprint, the subjects ran 6 ´ 800 m at intensities between 87% and 97% of v3km; endurance test (ET) ± 30 min at the velocity of IAT. Capillary blood (25 ll) was col- lected for [La)]b and [Glc]b measurements. The IAT and IGT were determined by [La)]b and [Glc]b kinetics during the second test. The Laÿ min and Glcmin were de- termined considering the lowest [La)] and [Glc]b during the third test. No di€erences were observed (P < 0.05) and high correlations were obtained between the veloc- ities at IAT [283 (SD 19) and IGT 281 (SD 21) m. á min)1; r = 0.096; P < 0.001] and between Laÿ min [285 (SD 21)] and Glcmin [287 (SD 20) m. á min)1 r = 0.77; P < 0.05]. During ET, the [La)]b reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol á l)1 at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glcmin as well as by IAT and Laÿ min.