Effect of alkalosis on plasma epinephrine responses to high intensity cycle exercise in humans.
The purpose of this study was to determine the effects of alkalosis on epinephrine concentrations in response to a 90 s maximal exercise test. A group of ten healthy men ingested either a bicarbonate (BS) supplement (0.3 g x kg(-1) of body mass of sodium bicarbonate) or placebo mixture (P) prior to performing a 90 s maximal cycle ergometer test. An indwelling Teflon cannula was placed in the antecubital vein and blood samples were drawn at three times at rest separated by 10 min, immediately following the protocol, and at 2.5, 5, and 10 min post exercise to determine plasma epinephrine concentrations. Sodium bicarbonate ingestion significantly ( P<0.05) induced alkalosis both at rest [mean (SD) pH=7.42 (0.02) BS, 7.38 (0.02) P] and after the exercise protocol [pH=7.16 (0.02) BS, 7.12 (0.02) P]. Plasma epinephrine concentrations were not significantly different immediately post exercise between the two conditions [4.2 (0.6) compared to 4.2 (0.7) pmol x ml(-1) in BS and P, respectively]. Work performed and power output attained were not significantly different between the two treatment conditions [mean power=258.7 (35.1) W BS, 260.3 (35.4) W P; peak power=534.7 (61.6) W BS, 535.7 (54.4) W P]. The primary finding of this investigation was that orally-induced alkalosis does not significantly affect plasma epinephrine concentrations or performance following 90 s of maximal cycle exercise in untrained men.
Marx
James O
JO
Laboratory for Sports Medicine, The Pennsylvania State University, University Park, PA 16802, USA.
Gordon
Scott E
SE
Vos
Netty H
NH
Nindl
Bradley C
BC
Gómez
Ana L
AL
Volek
Jeff S
JS
Pedro
Jerome
J
Ratamess
Nicholas
N
Newton
Robert U
RU
French
Duncan N
DN
Rubin
Martyn R
MR
Häkkinen
Keijo
K
Kraemer
William J
WJ
D000136:Acid-Base Equilibrium / Q000502:physiology; D000328:Adult; D000471:Alkalosis / Q000503:physiopathology*; D001639:Bicarbonates / Q000008:administration & dosage; D001642:Bicycling / Q000502:physiology; D002648:Child; D004837:Epinephrine / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*
D001639:Bicarbonates; D019344:Lactic Acid; D004837:Epinephrine