Effect of an acute β-adrenergic blockade on the blood glucose response during lactate minimum test
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Data
2001-10-25
Autores
Júnior, Pedro Balikian
Neiva, Cassiano Merussi
Denadai, Benedito Sérgio [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sports Medicine Australia
Resumo
The aim of this study was to determine the relationship between blood lactate and glucose during an incremental test after exercise induced lactic acidosis, under normal and acute β-adrenergic blockade. Eight fit males (cyclists or triathletes) performed a protocol to determine the intensity corresponding to the individual equilibrium point between lactate entry and removal from the blood (incremental test after exercise induced lactic acidosis), determined from the blood lactate (Lacmin) and glucose (Glucmin) response. This protocol was performed twice in a double-blind randomized order by ingesting either propranolol (80 mg) or a placebo (dextrose), 120 min prior to the test. The blood lactate and glucose concentration obtained 7 minutes after anaerobic exercise (Wingate test) was significantly lower (p<0.01) with the acute β-adrenergic blockade (9.1±1.5 mM; 3.9±0.1 mM), respectively than in the placebo condition (12.4±1.8 mM; 5.0±0.1 mM). There was no difference (p>0.05) between the exercise intensity determined by Lacmin (212.1±17.4 W) and Glucmin (218.2±22.1 W) during exercise performed without acute β-adrenergic blockade. The exercise intensity at Lacmin was lowered (p<0.05) from 212.1±17.4 to 181.0±15.6 W and heart rate at Lacmin was reduced (p<0.01) from 161.2±8.4 to 129.3±6.2 beats min-1 as a result of the blockade. It was not possible to determine the exercise intensity corresponding to Glucmin with β-adrenergic blockade, since the blood glucose concentration presented a continuous decrease during the incremental test. We concluded that the similar pattern response of blood lactate and glucose during an incremental test after exercise induced lactic acidosis, is not present during β-adrenergic blockade suggesting that, at least in part, this behavior depends upon adrenergic stimulation.
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Palavras-chave
Beta adrenergic receptor blocking agent, Placebo, Propranolol, Adult, Beta adrenergic receptor blocking, Beta adrenergic stimulation, Clinical trial, Controlled clinical trial, Controlled study, Exercise, Exercise test, Glucose blood level, Human, Lactate blood level, Lactic acidosis, Male, Normal human, Randomized controlled trial, Acidosis, Lactic, Adrenergic beta-Antagonists, Adult, Blood Glucose, Double-Blind Method, Exercise, Heart Rate, Humans, Lactic Acid, Male, Propranolol, Reference Values, Sports
Como citar
Journal of Science and Medicine In Sport. Dickson: Sports Medicine Australia, v. 4, n. 3, p. 257-265, 2001.