As their name implicates, these drugs stimulate our central nervous system. These drugs stimulate the brain to reduce tiredness while increasing alertness, competitiveness and aggressiveness. They can enhance explosive power and endurance performance because one can exercise more strenuously and is less sensitive to pain.

The stimulants comprise several different groups of substances:

are used in sports to enhance endurance, sharpen reflexes and reduce tiredness. The health risks to the athlete are considerable as evidenced by several amphetamine-linked deaths during arduous effort. Amphetamine-induced heatstroke and cardiac arrest are two major catastrophic events. In addition, amphetamines are known to produce dependence.

is the most potent naturally occurring stimulant and probably the most addictive agent known. Its misuse is linked to its euphoric effects and a feeling of decreased fatigue. Its increasing use as a recreational drug highlights the lifestyle pressures faced by some players. In fact, cocaine accounts for about one-third of all positive doping controls in football.
Cocaine users usually feel an initial "rush" or sense of well-being, of having more energy and being more alert. This effect quickly wears off, often leaving the user feeling more "down" or depressed than before. Contrary to popular belief, cocaine does not really enhance performance, whether on the job, in sport, at school or during sex.

Ephedra alkaloids
are naturally occurring stimulants obtained from ephedra plant species. Ephedrine is likely to be misused for its stimulant effect but it could also be inadvertently ingested because of its wide availability in over-the-counter medications mainly as a decongestant and in numerous nutritional and dietary supplements as an energy stimulant and anorexic agent. Research shows that isolated use of ephedrine, pseudoephedrine and phenylpropanolamine at dosages typically found in medications has only an inconsistent, and probably insignificant, ergogenic benefit for power, endurance, strength and speed.

You should know about the dangers and pitfalls of using stimulants.