in a linear fashion with increasing dosage.
Improvements in performance, however, did not
follow the increasing levels of blood bicarbonate,
with the highest amount of work being per-
formed after a dosage of 300 mg · kg-^1 , although
there were no significant differences between
300, 400 or 500 mg · kg-^1.
In another approach to answering the question
of sodium bicarbonate and performance, Kinder-
mann et al. (1977) intravenously induced
metabolic alkalosis by infusing an 8.4% sodium
bicarbonate solution until the arterial pH
reached 7.5. They then had subjects exercise by
running 400 m, but found no difference in perfor-
mance when they compared them with perfor-
mance in a control run. Similarly, Wijnen et al.
(1984) found no differences in the fifth bout of an
interval exercise regimen on a bicycle ergometer
when NaHCO 3 was administered intravenously
in a dosage of 180 mg · kg-^1. Again, this was
despite finding a significant increase in pH in the
30 min prior to the exercise test. In a second stage
of this study (Wijnen et al.1984), the authors used
a higher dosage and found that a greater number
(80%) of their subjects performed significantly
better than in the control trial.
Exercise time
A further question to be asked is, ‘Over what
time period is sodium bicarbonate effective?’
The plethora of research papers examining the
ergogenic benefits of NaHCO 3 have used time
periods ranging from 30 s (McCartney et al.1983)
to 6 min (McNaughton & Cedaro 1991a).
McCartney and colleagues (1983) had six
subjects perform 30 cycle ergometer tests in a
control, an alkalosis and two acidotic trials, one
caused by ammonium chloride ingestion and a
respiratory acidosis trial caused by inhalation of
a 5% CO 2 mixture. There were small, but not
significant, differences in the amount of work
accomplished by the subjects. In the alkalotic
trial, the work accomplished was 101% of
control, suggesting a difference of 0.3 s (over a
30-s trial), not statistically different, but certainly
practically so!
We (McNaughton et al.1991) investigated the
effects of bicarbonate loading on anaerobic work
and maximal power output during exercise of
60 s duration. The dosage of NaHCO 3 used was
400 mg · kg-^1 body mass with a control and
placebo trial which were randomly assigned tobicarbonate and citrate 399
40Control Placebo 100 200 300 400 500
Level of bicarbonate ingestion (mg)Blood bicarbonate (mM)3020100Fig. 29.3Bicarbonate levels in the blood after the ingestion of different levels of sodium bicarbonate, before and
after exercise. , before exercise, , after ingestion; , after exercise. From McNaughton (1992a).