If You Booze After Exercise, Your Muscles Lose
Or at least you don't gain as much as you otherwise would.
A wee nip, or two, or three after competition is a common occurrence for college and professional athletes, runners, and intramural -- "beer league" -- sports players. Even gym rats are occasionally known to attend a happy hour post workout. While most have an inkling that boozing after intense physical activity isn't the wisest course of action, a new study published in PLoS ONE apprises us all of precisely how unwise it is. According to a team of Australian exercise scientists, imbibing alcohol after exercise impairs rates of protein synthesis in recovering muscles, a process key to repairing and rebuilding damaged muscles.
In the study, eight physically active young adult males completed a strenuous exercise regimen combining weightlifting, endurance cycling, and interval training on three separate occasions, with each separated by a two-week rest period. After each bout, researchers provided subjects with varying nutrition. In the first instance, subjects received two servings of 25 grams of protein immediately and four hours after exercise. In the second, subjects received the same levels of protein but also were given alcohol. In the third, subjects received carbohydrates instead of protein and were given alcohol. The alcohol dose -- which was intended to mirror levels of binge drinking reported among sports teams -- was administered as such: subjects consumed screwdrivers containing two shots of vodka (hopefully good vodka) every thirty minutes starting one hour after their workouts. So they got pretty hammered. In the non-alcoholic instance, subjects simply drank orange juice every thirty minutes.
Using muscle biopsies and blood draws to gather data, the researchers found that alcohol significantly reduced protein synthesis by 24% and 37% in the alcohol-protein and alcohol-carbohydrate treatments respectively, compared to the protein treatment. (See above graph. "Rest" is the rate of synthesis with no exercise or nutrition treatment whatsoever.) Scientists have previously speculated that alcohol inhibits post-workout protein synthesis, but the current study is the first to gauge the reduction in humans.
"Alcohol ingestion suppresses the anabolic response in skeletal muscle and may therefore impair recovery and adaptation to training and/or subsequent performance," the authors said of the results.
In the long term, "the athlete who binge drinks after training is likely to benefit less from strength training-induced muscle growth," lead researcher John Hawley added.
The researchers briefly expounded upon a theory to account for the impairment.
"Alcohol consumption generates oxidative stress and inflammation and the potential to disrupt endoplasmic reticulum homeostasis," they wrote. The endoplasmic reticulum is an organelle that folds proteins and ships them around the cell.
Something to note: the authors looked at the effects of binge drinking -- not moderate drinking -- on protein synthesis. Moderate alcohol intake likely wouldn't result in such a marked reduction, though that remains to be studied.*
Since most athletes care about their body to some degree, the authors hope that their evidence will prompt them to adopt more moderate drinking practices. Some studies have shown that, while athletes are healthier overall, they are more likely than the general population to drink to excess.
Source: Parr EB, Camera DM, Areta JL, Burke LM, Phillips SM, et al. (2014) Alcohol Ingestion Impairs Maximal Post-Exercise Rates of Myofibrillar Protein Synthesis following a Single Bout of Concurrent Training. PLoS ONE 9(2): e88384. doi:10.1371/journal.pone.0088384
*Section added 2/21