Alcohol and Driving: Why it’s Not Safe to Drink and Drive Published Dec. 7, 2020 By Guy Leahy Health Promotion Flight KIRTLAND AIR FORCE BASE, N.M. -- During the holidays there always seems to be a renewed focus on preventing drunk driving…this year is no different. In 2018, 10,511 American lives were lost due to drunk driving. In 2019, New Mexico recorded 107 drunk driving fatalities (5th highest in the nation). Deaths from drunk driving are especially tragic, as such deaths are 100% preventable. How does the body handle alcohol once consumed? Alcohol is a toxin, so your body starts to eliminate alcohol as rapidly as possible. Once ingested, alcohol leaves the stomach and small intestines, and is transported to the liver via the portal vein. A small amount of alcohol is detoxified in the stomach, but the liver is the primary site. Once there, the liver uses two enzymes (enzymes are proteins which accelerate chemical reactions) to detoxify the alcohol to harmless products. This process is known as metabolism, and the products are called metabolites. The first step in liver alcohol detoxification occurs when an enzyme known as alcohol dehydrogenase (ADH) interacts with alcohol to oxidize it. The primary metabolite of alcohol oxidation is acetaldehyde. This product is fairly toxic, and is responsible for the “hang-over” effects (headaches, nausea, increased heart rate, etc.) of consuming alcohol. The second step is when the liver uses a second enzyme, acetaldehyde dehydrogenase (ALDH) to metabolize acetaldehyde to an inactive metabolite called acetic acid. Acetic acid is eventually converted to carbon dioxide and water. Most alcohol ingested is metabolized by this process. A small amount (5%-10%) escapes the liver, and circulates throughout the body as an active drug. This alcohol is eventually eliminated via breathing (this is the basis for breathalyzer tests,) and in the urine (alcohol is a strong diuretic). The liver contains enough ADH to metabolize all the alcohol in one standard drink. This equals one 12 oz beer at 5% alcohol by volume (ABV), one 5 oz wine at 12% ABV, or a 1.5 oz liquor at 40% ABV within 1-2 hours. However, more than one drink of alcohol will completely saturate the available ADH, so this excess alcohol will not be metabolized by the liver, and accumulates in the blood and tissues. This accumulation raises the blood alcohol content (BAC). The legal limit for BAC is .08. However, some impairment is seen at a BAC of .02 and in 2018, 1,878 fatal crashes involved drivers with a BAC of .01-.07. It doesn’t take much alcohol to exceed a BAC of .01%. For example, one drink consumed by a 170 lbs. male raises BAC to .02% and may take approximately one hour to return to a BAC of .0%. If the same individual consumes two drinks, BAC rises to .05% and may take about 3 hours to return to .0%. For a 150 lbs. female, the results will be similar for one drink, but for two drinks, BAC increases to .06%, and it will take 4 hours to return to .0% BAC. At a BAC level of .05, drivers have a reduced ability to track moving objects, difficulty steering, and a reduced response to emergency driving situations. Such drivers may also exhibit lowered alertness, impaired judgement and a loss of small muscle control (such as focusing your eyes). Being a responsible driver is simple; if you are drinking, do not drive. Ways to be a responsible driver include: Plan your safe ride home before you start the party and choose a non-drinking friend as a designated driver. If someone you know has been drinking, do not let that person get behind the wheel. Take their keys and arrange a sober drive home. If you drink, do not drive for any reason. Call a taxi, ride hailing service, or a sober friend. If you’re hosting a party where alcohol will be served, make sure all guests leave with a sober driver. Always wear your seatbelt - it’s your best defense against impaired drivers. If you see an impaired driver on the road, contact local law enforcement. Your actions could help save someone’s life.