Substances that speed up parts of the brain and body.
Adrenaline is a naturally occurring stimulant in the body, other unnatural sources are amphetamines and caffeine.
Benefits: Reduce fatigue, increase alertness & aggression, reduce reaction time suppress appetite, deaden pain of injury.
Side effects: Insomnia, high blood pressure & heart rate and body temp, strokes, addiction, heart & liver problems, increased risk of injury, death.
Sports: Sprinters, speed swimmers and cyclists, boxing, rugby.