Alcohol’s Effects on Exercise and Performance

Drink BeerAlcohol: What is it?

Ethyl alcohol, also known as ethanol, is found in beer, wine, and liquor. It is produced through the fermentation of yeast, sugars, and starches. Humans have consumed alcohol for many thousands of years, both intentionally and unintentionally.

Alcohol is a depressant that affects the human body in several different ways, and can have dire consequences if abused. It affects metabolism, neural function, cardiovascular physiology, thermoregulation, and skeletal muscle (1). Physiology, behavior, and impairment are progressively affected by a person’s blood alcohol content (BAC). This is the amount of alcohol that is circulating through the bloodstream. Impairment becomes progressively worse as BAC rises. This impairment includes the ability to concentrate and reason; it also affects vision, reflexes, speech, memory, motor skills, and organ function.

Further, alcohol consumption progressively affects behavior by causing mild euphoria, relaxation, decreased inhibition, amplified emotions, stupor, and even loss of consciousness. All of this happens because once the liver becomes unable to metabolize alcohol, it enters the bloodstream and is absorbed in other parts of the body such as the brain. This can be particularly dangerous because quickly drinking excessive amounts of alcohol will have a delayed effect. As the liver reaches its capacity for metabolizing alcohol, the leftover alcohol goes elsewhere. If a person stops drinking, his or her BAC will still continue to rise until the liver is able to catch up.

Effects at various BAC Levels:

.020 – Light to moderate drinkers begin to feel some effects

.040 – Most people begin to feel relaxed

.060 – Judgment is somewhat impaired

.080 – Definite impairment of muscle coordination and driving skills

.100 – Clear deterioration of reaction time and control

.120 – Vomiting usually occurs

.150 – Balance and movement are impaired. Here the equivalent of a 1/2 pint of whiskey is circulating in the blood stream.

.200 – Most people begin to experience blackouts

.300 – Many people lose consciousness

.400 – Most people lose consciousness and some die

.450 – Breathing stops. This is a fatal dose for most people.

Among active people, alcohol is the most commonly consumed drug (2). This remains true despite the detrimental effects it has on performance. Performance-wise, alcohol interferes with proper nutrition, recuperative sleep, hydration levels, muscle recovery, stress hormone levels, and the immune system.


Alcohol contains calories, but provides no nutritive function to the body. Yielding 7 kilocalories per gram, it is almost on par with the amount dietary fat yields (9 kilocalories per gram) (1). This is a reason why people who drink socially sometimes have trouble losing or maintaining their weight. The alcohol provides “empty” or non-nutrient containing calories.


Sleep is an important factor in recovery for active populations. Alcohol disrupts the Rapid Eye Movement (REM) and various other stages of sleep (3). It is during REM, or the deepest part of sleep that our bodies repair the damage incurred from training.


Alcohol also acts as a diuretic by inhibiting anti-diuretic hormone (ADH). Ingestion promotes excess urine production and evacuation very similar to caffeine. It has also been shown to act as a peripheral vasodilator. This increases the amount of fluid lost through sweat, on top of what is normally lost during exercise.

Disrupts muscle building

Muscle building is disrupted by alcohol due to the body’s prioritization of metabolization. Alcohol receives priority over the other nutrients the body requires most for recovery and growth after a hard workout. This reprioritization can also contribute to creating an environment of malnutrition which can eventually lead to other health problems such as osteoporosis.

Increases cortisol production

Alcohol ingestion also increases cortisol production (4). Cortisol is a stress hormone that is known to cause a variety of different problems such as inhibiting testosterone production, decreasing bone density, and increasing abdominal fat. Increased cortisol production also depresses the immune system causing it to function poorly and increases the likelihood of getting sick.

Decreased reaction time

Lastly, even days after consumption, alcohol can still cause neural and physical deficits (5, 6). Being hung-over brings more than just a headache. Cognitive ability may still be impaired, as well as reaction time.

Absorption of alcohol starts in the mouth and esophagus where small quantities immediately enter the bloodstream. It then continues in the stomach, and finally, most is absorbed in the small intestine. When someone drinks alcohol on an empty stomach, it is absorbed at a more concentrated level. To rid itself of alcohol, the body metabolizes alcohol in the liver in small quantities while the rest diffuses and circulates throughout the body and is excreted through other mediums such as sweat, urine, and breathing. Blood alcohol concentration peaks at about 40 minutes after drinking, drinks are absorbed within an hour, but it will take another 6 hours to metabolize the absorbed alcohol.

As a professional, it is important to stay mindful of the effects alcohol has on the human body. Clients are likely to ask questions surrounding its effects on performance as well as how it relates to weight loss, or lack thereof. Understanding how alcohol affects the body allows you to readily answer these questions appropriately as they relate to your individual clients.

  1. Insel P, Ross D, McMahon K, Bernstein M. Nutrition.4th ed. Sudbury, MA: Jones & Bartlett Publishers; 2011
  2. O’Brien CP, Lyons F. Alcohol and the athlete. Sports Med.2000; 29(5):295-300
  3. Roehrs T, Roth T. Alcoholic hangover and performance: a review. Alcohol Res Health. 2001;25(2):101-109
  4. Badrick E, Bobak M, Britton A, Kirschbaum C, Marmot M, Kumari M. The relationship between alcohol consumption and cortisol secretion in an aging cohort. J Clin Endocrinol Metab. 2008;93:750–57
  5. National Institute on Alcohol Abuse and Alcoholism. Alcohol’s damaging effects on the brain. Alcohol Alert. October 2004; 63. Accessed May 21, 2012.
  6. Lemon J. Alcoholic hangover and performance: a review. Drug Alcohol Rev. 1993; 12(3):299-314