The ergogenic effect of sodium bicarbonate ingestion on trained male 400 and 800 metre runners

Wood, R.J., 'The ergogenic effect of sodium bicarbonate ingestion on trained male 400 and 800 metre runners', honors Thesis, The University of Western Australia, 1991.

The effect of sodium bicarbonate ingestion on certain blood variables and concomitant effect on performance was examined over two studies. The aim of the first study was to determine the magnitude and time course of changes to various blood variables following three doses of sodium bicarbonate, and therefore determine the appropriate time after ingestion for exercise to be performed. Ten male subjects (24.3 ± 4.1 years) were tested on three occasions, ingesting, in random order, either 0.2, 0.275 or 0.35 g.kg-1 sodium bicarbonate. Blood samples were drawn from the ear lobe at 7 points in time; before ingestion, and at 30, 60, 75, 90, 105, and 120 minutes post-ingestion. The blood samples were analyzed for pH, [HCO3-], pCO2, PO2 and base excess (BE). The results showed the blood pH, [HCO3-], and BE were significantly elevated from 30 to 120 minutes post-ingestion for all doses, with the peak blood levels occurring between 90 and 120 minutes post-ingestion. There was no significant difference between doses in the magnitude of blood changes.

The second investigation studied the possible ergogenic effect of bicarbonate ingestion. Ten highly trained male 400 and 800 meter runners (19.3 ± 1.8 years), were tested on two occasions. In a randomly assigned order, they ingested either 0.275 g.kg-1 sodium bicarbonate (NaHCO3) or a placebo (CaCO3) over 15 minutes. The 0.275 g.kg-1 dose in study one reached peak blood levels at 90 minutes post-ingestion. Therefore, in this study, the subjects completed a treadmill ergometer run at 90 minutes post-ingestion. This involved running at 18 km.hr-1 and 10% gradient, to volitional exhaustion. Blood samples were drawn pre-ingestion, 60 and 90 minutes post-ingestion, and at 4, 7, and 10 minutes post-exercise, and [HCO3], pH, BE, pCO2 and [La-] determined.

The ingestion of sodium bicarbonate resulted in elevated pre-exercise blood pH, [HCO3] and BE. Post-exercise blood pH, [HCO3], BE, and [La1] were significantly greater for the bicarbonate condition compared to placebo. The time to exhaustion was greater (p <0.05) following bicarbonate ingestion (121.2 ± 21.4 seconds) than following a placebo (114. ± 21.4 seconds). Post-exercise urine pH was measured and found to be significantly greater after bicarbonate ingestion (7.5 ± 0.4) than after the placebo (5.5 ± 0.3).

It was concluded that the ingestion of sodium bicarbonate had a significant ergogenic effect on the time to exhaustion for a maximal treadmill run, lasting approximately two minutes, for trained male 400 and 800 meter runners. The elevated post-exercise urine pH following bicarbonate ingestion indicated that it would be possible to detect the use of sodium bicarbonate using standard dope testing procedure.

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