Caffeine In Sports Performance
by Patrick Traylor
Caffeine has long been considered as a substance capable
of enhancing physiological function (Jacobson 1987). As a
result of its reported ergogenic effect, the IOC has banned
the use of high levels of caffeine. At that time 15 mg ml-1
in urine was considered too much, this would be the equivalent
to 5-6 cups of coffee in 1-2h time period (Jacobson, 1989).
Caffeine is a trimethylxanthine compound that is not produced
by the human body and therefore athletes take caffeine supplements
in order to enhance their ability. I will look at a few studies
proving that caffeine has a positive effect of exercise ability
and also try to give a few reasons why caffeine may do this.
(1992) conducted a study with 32 subjects all of whom were middle
distance runners or county or national level. The results showed
that after the ingestion of caffeine the average 1500m times decreased
by 4.2s in comparison to a decaffeinated drink (P<0.005). Also
statistically significant increases in running speed were observed
after the ingestion of caffeine. The mean increase was 0.6kmh-1
which over a period of 1min would correspond to a distance of 10m.
VO2 data also showed a higher VO2 value during the caffeine-induced
run in comparison to the run without caffeine (P<0.025). Total
work performed during caffeine trails averaged 277.8±26.1kJ
whereas the mean total work during the placebo trial was 246.7±21.5kJ
(P<0.05) (Cole, 1996).
The evidence for beneficial effects of caffeine on performance
seems strong, and this is usually attributed to its stimulation
of adrenaline release which increases mobilization of fatty acids,
this resulting in a glycogen sparing effect (Graham, 2001). This
is countered by Raguso et al (1996) who stated that theophyllin,
structurally and pharmacologically similar to caffeine, failed to
alter either the rate of appearance or disappearance of FFA’s
or glycerol. There have been a few studies done on caffeine’s
on PRE and how it decreases it with the ingestion of caffeine (Doherty,
2005., Hudson et al. 2008). Graham (2001) proposed that this could
be due to stimulatory effects on the brain by an action on adenosine
receptors. This increases mental arousal and modifies the perception
of effort and therefore could allow the increase of exercise duration
Wiles (1992) showed that ingestion of 3g of caffeinated coffee
could enhance oxygen uptake and running performance in sustained
high-intensity exercise. These results are backed up buy numerous
studies (Costill, 1993., Jacobson, 1987). The method of how it enhances
the physiological system is still unclear and needs more research
done on it in order to provide a clear-cut definition.
Cole, K.J., Costill, D.L., Starling, R.D., Goodpaster, B.H., Trappe,
S.W., Fink, W.J. (1996). Effect of caffeine ingestion on perception
of effort and sunsequent work production. Int J Sport Nutr. 6.1,
Costill, D.L., Dalsky, G.P., Fink, W.J. (1978). Effects of caffeine
ingestion on metabolism and exercise performance. Med Sci Sports.10,
Doherty, M., Smith, P.M. (2005). Effects of caffeine ingestion
on rating of perceived exertion during and after exercise: a meta-analysis.
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Graham, T.E. (2001). Caffeine, coffee and ephedrine: impact on
exercise performance and metabolism. Can J Appl Physiol. 26, 103–109.
Hudson, G.M., Green, J.M., Bishop, P.A., Richardson, M.T. (2008).
Effects of caffeine and aspirin on light resistance training performance,
perceived exertion, and pain perception. J Strenght Cond Res. 22.6,
Jacobson, B.H. (1987). Caffeine - effect on health and athletic
performance. Excel. 4, 14-15.
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of caffeine. Br J Sports Med. 23, 34-40.
Raguso, C.A., Coggan, A.R., Sidossis, L.S. (1996). Effect of theophylline
on substrate metabolism during exercise. Metabolism. 45.9, 1153-60.
Wiles, J.D., Bird, S.R., Hopkins, J. (1992). Effect of caffeinated
coffee on running speed, respiratory factors, blood lactate and
perceived exertion during 1500m treadmill running. Br J Sports Med.