Alcohol (ethanol) quickly crosses the blood-brain barrier and influences membranes, ion channels, enzymes, and receptors of neurons in the central nervous system. The effects of alcohol on the central nervous system include slowing nerve conductance, blocking release and synthesis of acetylcholine, decreasing serotonin turnover, increasing release of dopamine and glucose utilization in the brain. Temporarily alcohol stimulates noradrenergic system giving a boost of energy which is followed by a decrease of its activity associated with feeling of depression. In sport, alcohol may be consumed for its potential positive effects on psychological well-being, for reduction of tension and anxiety, enhancing effect of self-confidence and for promoting aggressiveness. For this reason alcohol is prohibited in-competition in sports such as archery, shooting and motorsports. Acting initially as a stimulant, alcohol ultimately depresses neurological function (impaired memory, visual perception, speech, motor co-ordination) in direct relation to blood alcohol concentration.