title: Metabolic and blood catecholamine responses to exercise during alkalosis.
abstract: The effects of metabolic alkalosis on muscle lactate accumulation and plasma catecholamine concentrations were studied in six highly trained subjects during short-term ergocycle exercises to exhaustion (375 W). The studies were performed after oral administration of NaHCO3 (alkalosis) and CaCO3 (placebo). There was a significant increase in resting blood pH after NaHCO3 ingestion (7.35 +/- 0.02) compared to placebo (7.27 +/- 0.02). A longer endurance time was achieved during alkalosis (75.3 +/- 8 s) than during control (61.5 +/- 2 s), but similar blood pH and HCO3- levels were found at exhaustion in both treatments. Metabolic alkalosis resulted in higher elevation in muscle lactate concentration (31.7 +/- 4.6 mmol.kg-1 wet weight) compared to control (17 +/- 4 mmol.kg-1 wet weight). Despite longer exercise duration in alkalosis, plasma norepinephrine and epinephrine concentrations at exhaustion were reduced by 30 and 34%, respectively. These results indicate that alkalosis increased muscle lactate accumulation during exhaustive exercise. These changes were associated with a reduced blood catecholamine response to exercise.
authors.affiliation: Department of Physiology, INSERM U296, Faculty of Medicine, CHU Henri Mondor, Créteil, France.
authors.forename: P
authors.initials: P
authors.lastname: Bouissou
authors.forename: G
authors.initials: G
authors.lastname: Defer
authors.forename: C Y
authors.initials: CY
authors.lastname: Guezennec
authors.forename: P Y
authors.initials: PY
authors.lastname: Estrade
authors.forename: B
authors.initials: B
authors.lastname: Serrurier
mesh_terms: D000328:Adult; D000471:Alkalosis / Q000097:blood / Q000378:metabolism*; D002395:Catecholamines / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007773:Lactates / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism
chemical_list: D002395:Catecholamines; D007773:Lactates