PINES 10 questions, 10 experts: Alcohol in sport
Presented by PINES at ACSM’s 2018 Annual Meeting
Alcohol has a strong link with sport. Manufacturers and purveyors of alcoholic beverages sponsor many sporting teams or events, and the cultural rituals around competition are enmeshed with the consumption of alcohol. Most sport dietitians, physicians and other health professionals working with athletes find it difficult to educate athletes about alcohol due to the attitudes around drinking and the lack of objective, sports-related information. At this PINES session held at the American College of Sports Medicine’s annual meeting (Minneapolis, May 30, 2018), respected researchers answered some questions athletes commonly ask regarding alcohol and sport performance.
Given that most of the alcohol consumed in sport is probably consumed after sport, what effect does a big night or a hangover have on performance the next day?
Dr. Louise Burke, Head of Sports Nutrition, Australian Institute of Sport
Heavy drinking is common after athletic events. For example, research with rugby players suggests they consumed an average of 13 units of alcohol post-game, with a range of 1 to 30 units.* No surprise, this high intake impaired their aerobic performance. Given research reports results that are the average (mean) for the whole group, you can only imagine the range of impairment with intakes of 1 to 30 units (<1 to 22 beers)! Other studies have reported athletes were less able to do repeated sprints (think soccer, hockey) and jumps (think volleyball, basketball).
*One unit equates to 10 grams of alcohol. For example: 150 ml (5 ounces) wine equates to 1.5 units; 1 30 ml nip of hard (40%) alcohol is 1 unit; 375 ml (13 oz.) bottle of 4.8% alcohol beer is 1.4 units.
What does heavy alcohol intake after exercise do to rehydration and refueling goals?
Dr. Ron Maughan, Visiting Professor, St. Andrews University
In well-fed athletes, a modest amount of alcohol is unlikely to have a negative impact. Glycogen resynthesis is impaired to a small extent by alcohol, but in the real world of sports drinking, athletes who drink a lot tend to make poor food choices (too many high fat foods with little nutritional value). This can hinder optimal muscle glycogen replenishment. Ensuring a good meal before starting to drink alcohol is probably a good idea.
Alcohol is a diuretic; one unit (10 g) of alcohol stimulates the formation of 100 ml of excess urine. The alcohol content of beer is low and has been diluted by a lot of water, so dehydrated athletes can rehydrate effectively by drinking beer. Whiskey and other spirits cause more water loss than they contribute. Eating salty snacks or foods while drinking beer or other beverages increases thirst—and attenuates the diuresis that normally accompanies ingestion of large volumes of fluid.
What impact does alcohol prior to exercise have on heat tolerance/dehydration during exercise?
Dr. Doug Casa, Professor, University of Connecticut
Research suggests pre-exercise alcohol contributes to slower running performance across a wide range of distances. Anecdotes, more-so than much-needed research, link pre-event alcohol with poor sleep, under-hydration, reduced heat tolerance, and decreased cognitive function. Dr. Casa reported that one major summer road race had 20 to 25 heat injuries one year. The common denominators among those heat-stricken runners tended to be pre-event alcohol consumption.
What does heavy alcohol after exercise do to weight control/optimal body composition goals?
Dr. Barry Braun, Professor, Colorado State University
Ultra-athletes who do high amounts of exercise and need to consume many calories to match their high energy output might benefit from a few beers. But for most athletes, alcohol is a source of unwanted calories. Five beers add 450 to 1,000 calories (average is about 750)—and that’s not counting the pepperoni pizza or nachos that come along with the beer when your inhibitions are lowered. Needless to say, maintaining a desired body weight is difficult for athletes prone to late-night drinking and eating. Water, on the other hand, is a calorie-free beverage.
What does heavy alcohol intake after exercise do to protein synthesis and adaptation goals?
Dr. Stewart Phillips, Professor, McMaster University
For athletes, “bad” things happen during exercise and “good” things happens during recovery when the athletes rehydrate, refuel, and repair (consume protein) their muscles. Adding alcohol to the recovery diet slows down muscle protein synthesis and adaptation processes. Dr. Phillips says alcohol does not make his list of “best recovery practices” for athletes to follow. He’s not begrudging anyone a glass or two of wine, but notes habitual drinking could be problematic.
Running legend Jim Fixx’s answer to the question “Is beer good for runners?” is, “Sure, if it’s the other guy drinking it.” Competitive athletes want to hang out in the non-alcohol group, so they can take advantage of the other athletes’ poor judgment.
What does heavy post-exercise alcohol intake do to sleep?
Dr. Shona Halson Australia Institute for Sport, Senior Physiologist
Alcohol might help you fall asleep faster, but it disrupts your sleep cycles so you get less restorative sleep. Alcohol alters body temperature, which can affect how well you sleep. It also aggravates snoring (due to relaxed muscles and a lower breathing rate) and sleep apnea, so your bed partner also gets sleep deprived. Plus, you have to go to the bathroom more often in the middle of the night. None of this will enhance athletic performance.
What does heavy alcohol intake after exercise do to muscle soreness, injury and inflammation?
Matthew Barnes, Massey University, New Zealand
In a study which involved damaging the quadriceps muscles in one leg (with 300 eccentric contractions) and then having the athlete consume 1 gram of alcohol per kilogram body weight (7 units for a 70 kg athlete), the subjects were unable to generate as much force with the damaged leg, compared to consuming a non-alcoholic beverage after exercise. Yet, when given 0.5 g alcohol/kg (3.5 units for a 70 kg athlete)), there was no negative effect. Additionally, alcohol does not appear to affect female athletes the same way ti affects males when consumed after damaging exercise.
When athletes perform exercise to which they are accustomed to doing, the negative effects are less pronounced. That is, 90 kg (200 lb) rugby players, after getting battered up in a game, can drink 2.29 g alcohol/kg body weight (20 standard drinks) and still effectively perform a vertical jump! As for inflammation, players who are conditioned to both their sport and to drinking alcohol do not have a significant inflammatory response.
As a sport dietitian, how do I address alcohol intakes in male and female athletes?
Kerry Leech, Sports Dietitian, Australia
Each sport has its own culture around alcohol. For example, rugby players tend to be heavier drinkers than soccer players, and male athletes tend to drink more than female athletes (although this is changing). Limiting alcohol in locker rooms can reduced intake, as well as using educational tips like converting the calories in alcohol into fast-food equivalents. That is, did you know that a 6-pack of beer equates to about two Big Macs…?
Why isn’t there more research on alcohol and sport performance? What are the challenges?
Dr. Doug Casa, Professor, University of Connecticut
Having better research on the effect of alcohol on hydration and athletic performance would be very helpful, but few institutions approve such studies. Plain and simple, research that involves alcohol + heat + high humidity does not get approved!
In the limited number of alcohol studies that have gotten approval, the researchers quickly learned the study is not over after the exercise tests are done. They now have to deal with tipsy athletes after the testing. This means monitoring and being responsible for a rowdy group for several additional hours. That can be a challenge…
The remaining alternative way to research alcohol is to do retrospective studies on athletes who have already been drinking. For example, researchers could track how much alcohol a rugby team drinks post-event, or how many runners in the medical tent had consumed alcohol the night before the road race.
Summarized by PINES Secretary and Boston-area sports dietitian Nancy Clark MS RD CSSD.
