Taken to its logical conclusion, we might just one day see runners competing on bicycles, boxers using swords, and broadjumpers wearing spring-loaded shoes. Using dope to enhance performance is not a new phenomenon. What is new is the number of substances now available to dopsters. A second class of stimulants are amines which imitate the action of adrenaline, the substance in the body which marshals energy reserves in times of emergency.
Concentrated caffeine constitutes a third class of stimulants, used to sustain endurance.
Among the negative effects of concentrated caffeine are raised cholesterol levels, metabolic changes, and sleeplessness. The problem with painkillers is that they don't kill pain, they mask it. Beta-blockers slow the heart, allowing more time for steady shooting of a bullet or arrow between beats. Taken in large doses, beta-blockers can be fatal. Since they decrease body fluid levels, diuretics are favoured by those who need to lower their weight quickly and temporarily.