Several years ago the well known exercise physiologist David Costill published his research on caffeine and the physical performance of long distance runners. This research has resulted in the faddish use of caffeine among some and a generally positive impression of caffeine that is not completely warranted. While caffeine may still be a fad among runners it has a long history of use among cyclists.
Although touted as an almost miracle performance enhancer make no mistake about it, caffeine is not for everybody. Caffeine is a powerful central nervous system stimulant whose effects diminish with increased usage; Larger and larger doses can become necessary to avoid withdrawal symptoms and sustain stimulation until you need a cup just to function normally. To avoid this habituation drink caffeine only during or before races and training. Many road cyclists limit their caffeine consumption to a bottle of coke diluted with water during training rides and the last half of longer races or a cup of drip coffee half an hour before shorter races.
Caffeine affects different people in different ways. For some it only causes uncomfortable 'nervousness', high blood pressure and stomach acid. A strong cup of coffee to someone who does not drink caffeine regularly can last all day and well into the night, leaving a groggy feeling the next day which can be remedied only with another cup. If you do drink more than a cup of coffee every day some cutting back would probably go far towards improving your riding quality. When a cup of coffee is no longer an option but a prerequisite for alertness and energy it is probably doing more harm than good. This is the negative side of drinking the stuff, moderation can be difficult.
Caffeine is also a powerful diuretic. This can mean serious health and performance dangers. Many riders do not drink enough fluids even without caffeine. For this reason it is best to avoid any form of caffeine during hot weather and drink more caffeine-free fluids than normal with any coffee, cola or tea. Remember, the fatigue caused by dehydration is indistinguishable from the normal fatigue of hard training.
With so many drawbacks why is caffeine so popular among endurance athletes in general and cyclists in particular?
The exact mechanisms of caffeine's effects are not well known but most likely due to altered levels of CNS neurotransmitters and the metabolism of circulating free fatty acids. Caffeine's primary benefit during exercise seems to be its effect on free fatty acid metabolism. When free fatty acids are used for fuel they spare glycogen, glucose and amino acids which would otherwise be metabolized. The net effect is to increase blood sugar (glucose) for use as muscle fuel. In other words, higher blood sugar levels for longer periods of time. This is also why coffee is popular among students. The brain functions exclusively on glucose, and higher blood sugar levels facilitate thinking. Among non-athletes the most popular effect of caffeine is not physical, but mental.
This stimulation, in the form of motivation, can be an advantage to an occasionally undermotivated athlete but be careful not to become too hyper before a race or ride. Excess stimulation can impair the ability to ride safely and intelligently.
The amount and type of caffeine consumed are significant determinants of its effectiveness. There are large qualitative differences between coffees, even though the total amount of caffeine might be similar. Better coffees are lower in acid, higher in caffeine and have a longer lasting effect. Ground coffees are generally preferable to canned or instant. Sodas are all basically similar except for taste, Coke and Mt. Dew (and Snapple) being the most popular among cyclists. Diet sodas are a good choice because of their fluid to caffeine ratio, taste, and lack of sugar. Tea is a popular choice among Europeans. I know one Belgian pro who rarely gets on his bike without a bottle full of Earl Grey and never drinks anything but water off the bike.
Along with the performance and health considerations of drinking caffeine there are ethical considerations to weigh. Caffeine is a stimulant and as such is banned in large quantities (6+ cups) by the UCI. There are those who would like to see caffeine banned completely, theorizing that this would place everyone on a more equal footing. Whether this is possible or not it is not at present seen as practical or desirable due, no doubt, to the popularity of caffeine among athletes and non-athletes worldwide.
(C) 1989, Roger Marquis (www.roble.net/marquis)