control during the dosing phase and throughout
the exercise. At the start of the final exercise
phase, pH in the bicarbonate treatment group
was about 7.41, while the control was 7.34 and
the acidic treatment was 7.19. At exhaustion, the
pH was 7.34, 7.26 and 7.14, respectively.
A number of studies in the early 1980s sug-
gested that ingestion of sodium bicarbonate
could be effective in performance enhancement.
Wilkes et al.(1983), conducting a field type study,
examined six well-trained competitive 800-m
runners and compared the effects of sodium
bicarbonate, placebo (calcium carbonate) and
control treatments. The substances were both
given over a 2-h period in a dose of 300 mg · kg-^1
body mass and water was taken ad libitum
(average intake was 504 ml). Each subject com-
pleted their normal 30-min warm-up prior to the
race. Each runner completed all three protocols,
thus acting as his own control. In the bicarbonate
condition, runners were 2.9 s faster, on average,
than in the control condition (P<0.05), while the
control and placebo results were not significantly
different. Control, placebo and bicarbonate mean
times (min : s) were, respectively, 2 : 05.8, 2 : 05.1
and 2 : 02.9. While not particularly fast, the
difference between control and bicarbonate
(2.9 s) might mean the difference between first
and last place within a race.
In work from our own laboratory, Goldfinch et
al.(1988) saw improvements in 400-m race per-
formance due to ingestion of sodium bicarbonate
in six competitive, trained runners. The experi-
mental design was similar to that of Wilkes et al.
(1983), but with a major difference: the bicarbon-
ate dose was 400 mg · kg-^1 body mass. This was
done deliberately in order to eliminate ambigui-
ties around dose size. The control, the calcium
carbonate placebo or the experimental treatment
were given over a 1-h period in a low-energy
drink to try to disguise the taste. Each of the sub-
jects ran as part of a two-man competitive race to
simulate, as closely as possible, real competition.
The mean time of the bicarbonate ingestion
group was 56.94 s, and was significantly better by
1.25 s (P<0.005) than the control and placebo,
which were not different from each other. The
time difference was equivalent to approximately
a 10-m distance at the finish, again enough to
warrant a first or last place finish.
A number of studies have also shown
NaHCO 3 loading to be ineffective in delaying
fatigue or improving performance. Katz et al.
(1984) exercised eight trained men at 125% of
their predetermined V.
o2max.in either a bicarbon-
ate or control condition. Bicarbonate was given
in a dose of 200 mg · kg-^1 body mass, while the
placebo consisted of NaCl. No significant differ-
ence between the two conditions was noticed. In
the bicarbonate condition, subjects cycled for
100.6 s, while with the placebo, the time to
exhaustion was 98.6 s. These results are of inter-
est, since even though pH and base excess (which
is the measure of extra base above normal, princi-
pally bicarbonate ions) after correction for
haemoglobin content (Guyton & Hall 1981) were
significantly elevated following ingestion of
sodium bicarbonate, no improvement in perfor-
mance was seen. In other words, the bicarbonate
increased the amount of buffer available to the
body, but this was not used. The pH values seen
after exercise in this experiment were lower in
the control condition, possibly suggesting the
subjects could have worked harder in the experi-
mental condition, thus utilizing the extra buffer
available. In another study from the same labora-
tory, Horswill and colleagues (1988) found no
difference in performance when subjects per-
formed four bouts of intense, 2-min sprint exer-
cise. Again, the levels of blood bicarbonate were
significantly elevated in two of the conditions
tested prior to the performance tests, as was
pH, but again this increased buffering capacity
did not result in improved performance by the
subjects.
A number of practical problems have arisen in
the study of sodium bicarbonate loading due to
the nature of the experimental paradigms used.
That is, there is no single method employed by
researchers in order to detect any benefit. While
this is a natural process in research, from a practi-
cal sporting point of view it is a hindrance, as ath-