pH of less than 6.8, whereas in the placebo group,
none was greater than a pH of 7.0. McKenzie
(1988) suggested using a pH of 7.0 as a baseline,
which would have captured 92% of the subjects
using NaHCO 3 in his study. Even though this
was the case in the McKenzie (1988) study, other
factors, such as vomiting, a high-carbohydrate
diet (results in metabolic alkalosis) (Greenhaff et
al.1987a, 1987b, 1988a, 1988b), a high-protein
diet (results in metabolic acidosis; Maughan &
Greenhaff 1991), a vegetarian diet and a low
glomerular filtration rate (Kiil 1990), can change
the alkalinity of the urine which normally ranges
from 4.5 to 8.2, thus giving a false positive result
(for a review, see Charney & Feldman 1989). It
would be virtually impossible to detect confi-
dently those who had used a buffering agent to
improve performance.
Conclusion
Several reviews on the use of substances to
induce metabolic alkalosis in order to improve
short-term maximal performance have been
written (Gledhill 1984; Heigenhauser & Jones
1991; Linderman & Fahey 1991; Maughan &
Greenhaff 1991; Williams 1992; McNaughton et
al.1993; Linderman & Gosselink 1994). Although
no firm conclusions can be drawn from the
plethora of research conducted, there does
appear to be some general agreement on a
number of factors. Firstly, both sodium bicarbon-
ate and sodium citrate are effective buffering
agents. Second, there is a minimum level of
NaHCO 3 or sodium citrate ingestion below
which no improvement in performance takes
place and this is approximately 200 mg · kg-^1
body mass; the optimum dosage would appear
to be only slightly higher, at 300 mg · kg-^1 body
mass. Dosages higher than 300 mg · kg body mass
do not appear to have any greater benefit to per-
formance. Higher dosages of sodium citrate may
be more effective than sodium bicarbonate, but
this has not yet been confirmed. Thirdly, these
buffering agents have no effect on performance
of less than 30 s but do enhance performance
between 1 and 10 min. Finally, these substances
may be effective in enhancing high-intensity
endurance performance but more work needs to
be conducted.Practical implications
Many substances used by athletes to improve
performance have been banned by such bodies
as the International Olympic Committee (IOC).
Presently, no ban exists for the use of sodium
bicarbonate or sodium citrate and they are hard
to detect. However, their use may be considered
a violation of the IOC Doping Rule which states,
at least in part, that athletes shall not use any
physiological substance taken in an attempt to
artificially enhance performance. An athlete may
attempt to legitimize the use of these substances,
however, by likening it to the use of carbohy-
drate loading. If athletes decide to use these
buffering agents, then they should do so for
short-term, high-intensity exercise only and
should use dosages of approximately 300 mg ·
kg-^1 body mass dose. The substances should be
taken in or with fluid, preferably water, and in
large quantities (0.5 l or greater). Subjects should
be made familiar with possible side-effects prior
to usage.References
Brooks, G.A. (1985) Anaerobic threshold: review of the
concept and directions for future research. Medicine
and Science in Sports and Exercise 17 , 22–31.
Bryant-Chase, P. & Kushmerick, M.J. (1988) Effects of
pH on contraction of rabbit fast and slow skeletal
muscle fibres. Biophysics Journal 53 , 935–946.
Charney, A.N. & Feldman, F. (1989) Internal exchanges
of hydrogen ions: gastrointestinal tract. In The Regu-
lation of Acid-Base Balance(ed. D.W. Seldin & G.
Giebisch), pp. 89–105. Raven Press, New York.
Costill, D.L., Flynn, M.G. & Kirwan, J.P. (1988) Effects of
repeated days of intensified training on muscle
glycogen and swimming performance. Medicine and
Science in Sports and Exercise 20 , 249–254.
Dennig, H., Talbot, J.H., Edwards, H.T. & Dill, B. (1931)
Effects of acidosis and alkalosis upon the capacity for
work.Journal of Clinical Investigation 9 , 601–613.
Dill, D.B., Edwards, H.T. & Talbot, J.H. (1932) Alkalosis
and the capacity for work. Journal of Biological
Chemistry 97 , 58–59.