Original articles   

The Journal of Sports Medicine and Physical Fitness 2001 December;41(4):456-62

Copyright © 2002 EDIZIONI MINERVA MEDICA

language: English

Acute versus chronic sodium bicarbonate ingestion and anaerobic work and power output

Mc Naughton L., Thompson D.

From the Department of Sport and Exercise Science University of Bath, Bath, England

Background. The aim of ­this ­study was to com­pare and con­trast the ­effects of ­acute ver­sus chron­ic sodi­um bicar­bo­nate inges­tion.
Methods. Participants: ­eight ­male, (­mean±SE): age, 20.8±0.4 yrs; ­height, 179.6±0.6 cm; ­body ­mass, 79.4±0.85 kg, Σ7skf, 48.6±4.8 mm, V.O2max=55.9±0.8 ml·kg-1·min-1) vol­un­teer sub­jects, ingest­ed NaHCO3 in ­either a ­dose of 0.5 g·kg-1 ­body ­mass acute­ly or the ­same ­dose dai­ly ­over a peri­od of six ­days in ­order to deter­mine wheth­er ­there ­were any dif­fer­enc­es in per­for­mance of 90 sec max­i­mal ­cycling ergom­e­try. Intervention: ­after sub­jects under­took an ­initial con­trol (C) ­test ses­sion, all ­were ­then ran­dom­ly ­assigned to one of two ­groups, ­acute or chron­ic NaHCO3 inges­tion. Subjects in the ­acute inges­tion (AI) ­group com­plet­ed ­their sup­ple­ment­ed ­test on day one, and ­then on the fol­low­ing day. Chronic inges­tion (CI) sub­jects com­plet­ed the ­test ­after one day of chron­ic inges­tion as ­well as fol­low­ing six ­days of bicar­bo­nate inges­tion. Following ten ­days ­rest, sub­jects repeat­ed the pro­to­col in the oppo­site ­group. Measures: ­blood sam­ples ­were tak­en pre- and ­postinges­tion, dai­ly, and pre- and ­postexer­cise and ­were ana­lysed for, pH, Base ­excess (BE), HCO3-, PO2, PCO2, Na+, K+, Cl-, and lac­tate.
Results. Both the chron­ic (CI) and ­acute inges­tion (AI) ­groups ­were sig­nif­i­cant­ly dif­fer­ent to the control (C) val­ue (p<0.001 and p<0.05, respec­tive­ly).
Conclusions. We ­would sug­gest ­using chron­ic inges­tion as a ­means to ­improve ­high inten­sity ­work rath­er ­than the ­acute inges­tion of sodi­um bicar­bo­nate. The inges­tion of sodi­um bicar­bo­nate, ­over a peri­od of six ­days, sig­nif­i­cant­ly ­improved ­work out­put two ­days ­after bicar­bo­nate inges­tion ­ceased.