Your blood alcohol content, or BAC, is expressed as a percentage that means milligrams of alcohol per 100 mg of blood, according to the University of Rochester in New York. Alcohol affects your central nervous system, reducing its activity. Alcohol's effects increase along with your BAC, such as trouble with fine motor coordination, advises Indiana University.
Buzz Zone
When your BAC is below 0.06 percent, you are in the "buzz zone," according to UR. You may experience higher self-confidence, increased energy, and a feeling of euphoria or well being. You may have minor memory and reasoning impairment and a lower than usual level of caution, according to IU.
Diminishing Return Zone
At 0.06 you reach "the point of diminishing returns," according to UR. As you pass this point, you start to feel alcohol's depressant effects including sluggishness, fatigue, loss of coordination and slurred speech. With a BAC of 0.07 to 0.09, your balance, vision, speech, reaction time and hearing are all slightly impaired. You still may feel euphoria, but your memory and reason are impaired, and your self-control and judgment are reduced, according to IU.
With a BAC of 0.10 to 0.125, your loss of judgment is significant, as is your motor coordination impairment. At this point you might slur your speech. Your reaction time slows and balance, hearing and vision are impaired. Your slower reaction times and decreased reflex responses are due to lowered heart rate, respiration rate and blood pressure, according to IU.
Control Loss
At a BAC of 0.13 to 0.15, you suffer lack of physical control. Your vision may be blurred and it may be hard to balance. Your euphoria may be replaced by dysphoria, meaning anxiety or restlessness, advises IU. With a BAC between 0.11 and 0.2, you may have emotional swings, ranging from boisterous to angry to sad, according to UR.
Danger Zone
After your BAC passes 0.21, you suffer a loss of understanding, may go into a stupor and may experience a "blackout," according to RU. At a BAC of 0.25 you likely need help to walk and may suffer complete mental confusion. You also might feel nausea or vomit, according to IU.
You can lose consciousness when you have a BAC of 0.3, and if your BAC reaches 0.4 or more you can go into a coma and may die due to respiratory arrest, according to IU. Death also is possible at a BAC of 0.3, according to UR.
