Alcohol does have an impact on athletic performance, but the effect depends on the quantity consumed, genetics, demographics, and exercise being performed. This makes it difficult to make exact recommendations for alcohol intake. However, there are a few things to consider with alcohol intake on athletic performance. In addition, there are very few studies on the performance effects of alcohol because performing such studies would be considered unethical.
The metabolism of alcohol is complex. It is first converted to acetaldehyde, which is a poison and closely resembles formaldehyde. This acetaldehyde is converted into acetic acid radicals, which combine with coenzyme A to form acetyl CoA. The acetyl CoA enters the Krebs cycle, which is the basic power house of the human body. This is where it will be broken down into carbon dioxide and water to provide energy. There are several enzymes that are needed to break down alcohol into acetaldehyde and then again into the acetic acid radicals. Certain genetic difference could influence how quickly the enzymes work to break down alcohol and this could be why some people tolerate alcohol better than others.
Drinking the occasional alcoholic beverage might be okay for some people. Of course, it is always wise to completely avoid alcohol if you have a risk of alcoholism or are in recovery for alcohol or any other addiction.
Alcohol has an effect on many systems in the body, but most pronounced are the effects of alcohol on neural function, metabolism, cardiovascular physiology, thermoregulation, and the muscle growth.
Alcohol's effect on athletic performance:
Decreased strength output by inhibiting the calcium channel actions in the sarcolemma (cell membrane that incloses each muscle cell) and in turn this impairs muscle contraction. These effects on the muscle can also cause a decrease in sprint performance and decreased power.
It delays muscle repair and therefor can decrease recovery after exercise.
Alcohol has a diuretic effect and it acts as a vasodilator. This causes a loss of fluid both through urination and by evaporation on the skin. This can cause a decrease in aerobic performance due to the effects it has on temperature regulation and increase in fatigue.
It has a blood sugar lowering effect. This is of particular concern for any athletes with type 1 diabetes. It impairs the liver's ability to make glucose and release glucose into circulation.
Alcohol may impair the utilization of glucose for fuel during exercise.
Alcohol reduces central nervous system activity and can slow reaction time and fine motor skills. These effects can last for several hours after alcohol is consumed.
If you drink alcohol after exercise it can impair the inflammatory response of exercise. This may sound like a good thing, but it is not. This inflammatory response if natural and part of the body's process for adaptation to training and recovery and repair of tissue. If this process if impaired it can impair recovery and can decrease the benefits of that exercise session.
Increases the risk of nutrient deficiencies. This is because alcohol can inhibit nutrient absorption and chronic alcohol intake can increase the need for certain B vitamins and thus increase the risk of deficiency of those nutrients.
Disrupts sleep because it disrupts restorative sleep cycles by impairing the ability for the body to get into the REM sleep and stay there. Often drinking may also mean late nights, which can impair sleep even further.
Increases risk of injury and illness due to impairment of the immune system.
Drinking alcohol after a resistance training session can increase cortisol and decrease the testosterone to cortisol ratio. This can cause a decrease in the exercise response to training and a overall impairment of the body's ability to grow and repair muscle.
Tips for drinking in moderation:
Choose alcohol beverages that also contain polyphenols, antioxidant and other health promoting compounds such as red wine. Choose a red wine that does not also contain preservatives.
Choose hard alcohols that have been triple distilled. This will help decrease other harmful byproducts that can come in the distillery process. This is particularly important for those who have Celiac disease, wheat or barley intolerance, or an autoimmune disease.
Drink a glass of water per every alcoholic drink. Hopefully you are not drinking more than one or two, but if you are, make sure to drink lot of water to decrease the diuretic effects.
Drink an electrolyte drink before bed. Preferably one that is low sugar and does not contain artificial dyes.
Be the designated driver! This is an important job and it means you have a great excuse to say no to alcohol.
References:
1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257708/
2) http://hams.cc/metabolism/
3) https://www.nsca.com/education/articles/nsca-coach/the-effects-of-alcohol-on-athletic-performance/
4) https://www.niaaa.nih.gov/alcohol-health