by Reiley Bergin, CSCS and Courteney Benjamin, CSCS
NSCA Coach November 2015
Vol 3, Issue 4
Alcohol use is widespread in the realm of sports. Consumption ranges from the weekend warrior guzzling a beer after completing a 5-k run to elite athletes popping champagne in the locker room after a championship win. Alcohol is often used as a means of celebration or relaxation, and athletes frequently consume drinks without much thought of the acute and chronic effects on performance and health. Alcohol’s path to oxidation is complex, and both short- and long-term use affects most systems of the body. Factors such as genetics, gender, amount of alcohol ingested, body mass, and nutrition status help explain the large variance in effects that alcohol has within and across individuals (1,4). From an athletic performance standpoint, the acute use of alcohol can influence motor skills, hydration status, aerobic performance, as well as aspects of the recovery process; consequently, influencing subsequent training and competitions (2,9). Chronic alcohol use can lead to difficulty in managing body composition, nutritional deficiencies, and depressed immune function, resulting in increased risk of injury and prolonged healing and return-to-play (2,17). While the acute and chronic effects of alcohol are largely dose-dependent, chronic and heavy intake can increase one’s risk of long-term health effects such as cardiovascular disease, liver disease, and cancer (4). The drinking habits of athletes, as well as the effects of alcohol, are highly variable, making a one-size-fits-all recommendation difficult and impractical. Furthermore, current research on the effects of alcohol on athletic performance is limited due to ethical concerns. This article will discuss the available evidence related to alcohol and athletic performance.
Blood alcohol concentration increases upon ingestion of alcohol. Soon after, the acute side effects begin to take place, which can result in depression of central nervous system activity. While the effects are dose-dependent, this can lead to compromised motor skills, decreased coordination, delayed reactions, diminished judgment, and impaired balance (3,9). These effects on the body may not only contribute negatively to athletic performance, but may also increase an athlete’s risk for injury. The effects of low to moderate doses of alcohol on anaerobic performance and strength are equivocal, but an aid to performance is not evident (9). Conversely, research has shown that even small doses of alcohol ingested prior to exercise led to a decrease in endurance performance (10). It appears that alcohol may affect aerobic performance by slowing the citric acid cycle, inhibiting gluconeogenesis, and increasing levels of lactate (12). Additionally, the body preferentially metabolizes alcohol, thereby altering the metabolism of carbohydrates and lipids, which are the preferred energy sources during endurance exercise (12). Although alcohol may have been viewed as an ergogenic aid in the past (likely for psychological reasons), the scientific evidence shows that alcohol hinders athletic performance, and ingestion prior to training or competition should be avoided. Alcohol is currently a banned substance for National Collegiate Athletic Association (NCAA) rifle competitions, and the World Anti-Doping Agency (WADA) prohibits alcohol consumption during air sports, archery, powerboating, and automobile competitions on the basis of it being considered an ergogenic aid (11,18).
The ingestion of alcohol prior to or during exercise is not very common. However, the intake of alcohol following an event is a much more likely scenario. To recover properly from exercise, it is important to replenish glycogen, stimulate muscle protein synthesis (MPS), and restore fluid balance. Alcohol and the behaviors associated with intoxication can interfere with many aspects of the recovery process. Beverages containing greater than or equal to 4% alcohol can increase urine output, ultimately delaying recovery from a dehydrated state (15). Beer has been plugged as a post-workout recovery beverage because it contains carbohydrates and electrolytes, but in actuality, the typical beer does not contain nearly enough carbohydrates or electrolytes for proper recovery from a long workout with a large sweat loss. It is reasonable to conclude that the negative effects of alcohol consumption after a workout outweigh any potential beneficial effects. To adequately replace lost fluids, it is important for athletes to drink rehydrating beverages such as sports drinks, or consume water with salty foods, prior to alcohol consumption. If immediate alcohol intake is inevitable, athletes should strive to only consume small volumes of alcohol.
Replenishing glycogen stores is another essential component to recovery, especially when the turnaround between training and competition is short. It is unclear if alcohol consumption after exercise directly affects glycogen synthesis; however, alcohol can indirectly displace carbohydrate and protein intake (5). When protein-rich foods are displaced with alcohol during the post-exercise recovery period, MPS is not optimally stimulated, which can potentially inhibit muscle growth and repair. Furthermore, there is evidence for a direct effect of alcohol on MPS. Researchers have found that alcohol significantly decreases MPS even when adequate protein is consumed (13). This effect has been investigated on resistance exercises, as well as exercises commonly carried out in team sport training (6). Overall, when an athlete chooses to fill up on alcoholic beverages during the recovery period they are less likely to follow optimal nutrition guidelines for recovery, resulting in a prolonged recovery period, inadequate recovery before the next training session or competition, or lack of desired muscular adaptations.
Beyond the energy storage and MPS implications, alcohol can also negatively affect sleep, recovery from injury, and the production of hormones associated with muscular growth (2). Athletes need adequate sleep to aid in recovery and to be able to perform at their best, both physically and mentally. Ingestion of alcohol before going to bed may help induce sleep, but has been shown to disrupt restorative sleep cycles throughout the night, decreasing quality of sleep (7). To compound this, when athletes enjoy a night out drinking, they may stay out later than normal, reducing their duration of sleep. These two factors combined may impact recovery, energy levels, and performance in upcoming training and competitions. When athletes experience soft tissue injuries, the body employs
an inflammatory response. Alcohol has been shown to limit the inflammatory response via an increase in the production of anti-inflammatory molecules and a decrease in pro-inflammatory molecules (2). In addition to an imbalance of the inflammatory response, alcohol also acts as a vasodilator, increasing blood flow to the injured area, which could possibly increase the severity of the injury and prolong the recovery (2). Therefore, consumption of alcohol is generally not recommended if an injury has recently occurred.
There are a number of hormones that affect muscle growth. For example, cortisol stimulates protein breakdown while testosterone increases protein synthesis. In recreationally trained athletes, research has found that high doses of alcohol intake after resistance exercise increased cortisol levels and decreased the testosterone-to-cortisol ratio, which can interfere with the adaptive process of long-term resistance training (8). Additionally, alcohol decreases testosterone secretion; therefore, excessive intake during the recovery period should be avoided for athletes striving for muscular hypertrophy or for those with hormonal imbalances (4).
The effects of alcohol do not simply wear off when signs of intoxication are gone. Heavy drinking can lead to an array of symptoms commonly referred to as a hangover. Athletes are not immune to hangovers, which can influence their training and competitions. The hangover symptoms produced by alcohol have many intra-individual variances. However, the main effects of hangovers include electrolyte imbalance, hypoglycemia, gastric irritation, vasodilation, and sleep disturbances (14). These effects cause an array of physical symptoms, which may leave an athlete feeling drained and unable to train as hard as normal. Research has shown an approximate 11% decrease in aerobic capacity in those exercising with a hangover (12). Effects of a hangover on anaerobic performance remain unclear, but overall it is probable that athletes training or competing without a hangover will enjoy a competitive edge over their hungover opponents.
There is evidence supporting health benefits from moderate alcohol consumption, but regular heavy consumption and binge drinking can take a toll on the body. Athletes are susceptible to the health effects associated with excessive alcohol consumption, which can also affect performance. Alcohol is calorically dense, providing seven calories per gram, with a standard drink in the United States containing 14 grams of alcohol (16). If other substances are present, such as soft drinks and sugar-based beverages, the caloric value of an alcoholic drink rises even higher. As a general reference, the following are common drink sizes and their average alcohol content: 12 oz of beer (5% alcohol), 5 oz of wine (12% alcohol), and 1.5 oz of 80-proof distilled spirits (40% alcohol) (16). The calories from alcoholic beverages can add up fast and contribute a significant amount of calories to an athlete’s overall caloric intake. Additionally, behaviors associated with heavy drinking, such as irregular eating patterns and increased consumption of unhealthy foods, may lead to increased caloric intake. Over time, this combination can affect an athlete’s body composition.
Heavy intake of alcohol can also lead to nutritional deficiencies. Athletes require a sound nutrition plan to promote optimal athletic performance, and may already be at a higher risk of nutritional deficiencies than their non-athlete counterparts due to the physical demands of training. Alcohol affects absorption and utilization of many nutrients. Excessive alcohol intake can reduce the intestine’s ability to absorb nutrients such as vitamin B12, thiamin, and folate. Additionally, liver cells can become inefficient at activating vitamin D and the metabolism of alcohol can destroy vitamin B6 (4). Nutritional deficiencies present many different problems to athletes and can have serious health and performance implications. In addition, long-term misuse of alcohol is associated with a higher risk of developing cardiovascular disease, liver disease, and cancer (4). It can also compromise the immune system and increase susceptibility to illness (2).
Overall, the effects of alcohol vary dramatically from person to person with many different contributing factors. The effects of alcohol on athletic performance vary depending on quantity, demographics, and type of exercise. Therefore, it is difficult to determine specific recommendations, but it is suggested that athletes follow the same recommended guidelines for safe and responsible drinking as the general public. Binge drinking is never recommended due to the side effects that interfere with desired athletic adaptations. The cumulative effects of binge drinking episodes may leave an athlete unable to perform at the expected or desired level. After an athletic event, athletes should be encouraged to follow recommended nutrition and hydration guidelines for recovery prior to alcohol consumption.
This article originally appeared in NSCA Coach, a quarterly publication for NSCA Members that provides valuable takeaways for every level of strength and conditioning coach. You can find scientifically based articles specific to a wide variety of your athletes’ needs with Nutrition, Programming, and Youth columns. Read more articles from NSCA Coach »
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