28 Nov, 2017

Caffeine Kick


In January 2004, caffeine was taken off the World Anti-Doping Agency (WADA) list of banned substances used in competitive sports, but earlier this year it was placed back on the WADA monitoring list, and may be put back on the list in 2018, once studies have been done this year. – BY CHRISTINE PETERS, REGISTERED DIETICIAN

Caffeine is the best known member of a family of naturally occurring stimulants found in leaves, nuts and seeds in over 60 plants, and dietary sources include tea, coffee, chocolate, soft drinks and energy drinks. Typically, these provide 20 to 200mg of caffeine per serving. The main source of caffeine in sports drinks, gels and supplements is guarana.

It's well-known that caffeine makes us more alert and delays sleep, and it's also popular among athletes, since it can improve performance in some sports. Caffeine has a complex range of actions on the body which have been extensively researched. It has several effects on skeletal muscle, and through some of these actions, caffeine may stimulate fat metabolism during aerobic exercise, ‘sparing’ glycogen stores and thus delaying fatigue.

However, other studies have found this effect to be short-lived and confined to certain individuals only. Caffeine has also been found to have other effects on the body that may influence athletic performance: It may affect the central nervous system, such as reduced perception of effort and enhanced recruitment of motor units, which may give athletes a ‘buzz’ and mask fatigue.

Caffeine Dose
Caffeine is rapidly absorbed, reaching peak concentrations in the blood within an hour after ingestion, and studies point to smaller amounts taken in throughout exercise being beneficial for performance, rather than one larger dose one hour prior to a bout of exercise. It’s also thought that as an athlete fatigues during exercise, they become more sensitive to small doses of caffeine. Looking at various studies, it seems that beneficial effects from caffeine occur at very modest levels of intakes (1 to 3mg/kg body mass or 70 to 150mg caffeine), when taken prior to or during exercise. (One cup of coffee can contain anywhere between 25 and 214mg caffeine.)

It is important to remember, however, that caffeine-loading is not good for all athletes. Like any drug, caffeine affects everyone differently. Some athletes will respond and receive a pronounced performance boost, whereas some athletes are non-responders, or may even experience disadvantageous side-effects that are detrimental to performance, such as tremors, increased heart rate, headaches and impaired sleep. However, contrary to popular opinion, caffeinated drinks do not dehydrate us, especially if we are used to caffeine.

In terms of long-term health, people often ask whether caffeine is safe. Right now, it appears that a moderate caffeine intake does not increase the risk of developing cardiovascular disease, osteoporosis or cancer, but as with most things, the most important thing to remember is everything in moderation! For the average healthy adult, moderate caffeine intakes pose no health risk, especially if we eat a balanced diet and enjoy regular physical activity.

About the Author
Christine is a registered dietician based in the Johannesburg area.

Christine Peters

Christine Peters

Registered Dietician |

Registered Dietician


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