Stimulants.

Introduction.

Stimulants is a name given to several groups of drugs that tend to increase alertness and physical activity. The groups include pharmaceuticals such as amphetamines and the street drugs such as cocaine, and even caffeine.

 
Amphetamines

The stimulant most commonly abused by athletes, are amphetamines. Amphetamines are sometimes prescribed by physicians, often to counter the effects of narcolepsy, their availability makes them prime candidates for misuse. 

Amphetamines increase alertness and physical ability, by increasing the heart and respiration rates, increasing blood pressure, and decreasing appetite. Useful for athletes where power to weight ratios are important, such as power lifting, and even gymnastics.

Side effects include anxiety, blurred vision, sleeplessness, and dizziness. Abuse of amphetamines can cause irregular heartbeat and even physical collapse. 

 Amphetamines are psychologically addictive. Users become dependent on the drug to avoid the
"down" feeling they often experience when the drug's effect wears off. This dependence can lead a
user to turn to stronger stimulants such as cocaine, or to larger doses of amphetamines to maintain a
"high". 
  Brolamphetamine, a common amphetamine.

Caffeine

Caffeine, a mild stimulant, is the most widely used psychoactive drug in the world. It is present in soft drinks, coffee, tea, cocoa, chocolate and numerous prescription and over-the-counter drugs, it can also be bought over-the-counter in tablet form.. It increases norepinephrine secretion and enhances neural activity in numerous brain areas. Tolerance occurs rapidly to the stimulating effects of caffeine.

  Caffeine, most people's pick-me-up.