Alcohol can reduce the health benefits of exercise, affect performance and recovery. Our body is always going through muscle protein synthesis by either building new proteins or breaking down proteins for muscle repair. With resistance exercise we stimulate muscle protein synthesis, which causes our body to repair and super compensate so we gain muscle.
In a study by Evelyn Parr, she looked at the rates of muscle protein synthesis post-exercise, so the participants would do a bout of exercise and then they’d consume alcohol. During the study muscle biopsies were taken to look at the changes in muscle protein synthesis. The studies showed when they consumed alcohol it reduced their muscle protein synthesis by 37%, which is a big reduction if we’re trying to look at optimising muscle recovery or even adaptation.
There were a few different groups in this study, the groups either consumed alcohol, alcohol and protein, or just protein. The results showed that even if you have alcohol and protein, your protein synthesis was still decreased by 24%. So that alcohol-induced reduction in muscle protein synthesis is going to have a significant effect on your recovery from that exercise, so you’re not going to get as good adaptations or as good results, and potentially it’s going to affect your next session as well.
In a separate study on the effect of the previous day’s alcohol ingestion on muscle function and performance. The participants did two lots of exercises two weeks apart, they do the testing procedure once, with no alcohol the night before, then again two weeks later where they’d consume alcohol the night before, and then exercise the next day.
In this study they controlled the amount of alcohol people have, so it’s standardized, participants were taking in 1.9 grams of ethanol per 1kg of fat-free body mass. This equalled out to roughly four standard drinks for males and around three standard drinks for the females. Then they tested a number of performance measures, comparing vertical jump and isometric mid-thigh pull – which is a maximal strength test, bicep curl test, which was a muscular endurance type test, and a high-intensity anaerobic threshold test on a cycle ergometer to time to exhaustion.
The vertical jump, bicep curl and the isometric mid-thigh pull didn’t show a lot of statistically significant difference the morning after, but there was a significant reduction in the time to exhaustion for the cycle ergometer test. So what they’ve shown is, having three to four standard drinks the night before is going to affect your ability to perform high-intensity exercise the next morning. Some exercise is better than no exercise, however it’s probably not going to be the maximal stimulus we can possibly get had we not consumed alcohol the prior evening.
A separate study measuring muscle damage and recovery had participants do 300 maximal, slow eccentric reps which caused a severe amount of DOMS, which they measured the effect of i.e. performance loss both with and without alcohol to compare results. They found that the greatest decrease was 36 hours after this exercise bout of 300 maximal eccentric reps. Performance had dropped around 31% for the group that didn’t have alcohol. For the group that did have alcohol, it was 40%, Which shows less recovery, but that performance decrement is going to take a longer time to recover from as well. This study relates well to any injuries if you’re performing a sport or where you sustain a soft tissue injury any alcohol after that, is going to affect your ability to recover in the long run.
In terms of trying to get the most of our training. If you’re a PT and clients are trying to optimize their results, alcohol is going to be detrimental to that i.e. If they’re coming in every week and they’re not recovering properly from their previous session, you’re not going to be able to give them as much work. So the less stimulus, the less results they’re going to get. It’s a trade-off. So is important to educate your clients about so they can moderate alcohol consumption, so it doesn’t affect their recovery and exercise stimulus, to achieve their health goals.
Fat loss or weight control is also a a very common goal that clients will have and alcohol affects that. There was a study done with overweight adults, that looked at intensive lifestyle intervention. The participants were going through an education process about losing weight and changing their lifestyle to do that. It was a longitudinal study over a number of years. Where they looked at some of the participants abstained from alcohol or continued their regular alcohol consumption. The group that abstained from alcohol lost 5% of their bodyweight in the first year of this study. The group that didn’t change their alcohol only lost on average 2.4%. So alcohol is going to affect the amount of weight loss.
There’s 29 kilojoules per gram of alcohol. So alcohol also is an energy source for our body and contributes to the amount of kilojoules we intake per day. Weight loss is a balance of energy in versus energy out. If we’re intaking more kilojoules than we’re expending, we’re going to gain weight. In one 150 ml of red wine, there’s roughly 578 kilojoules, In a can of beer there’s about 570 kilojoules, and any sort of shot of vodka, gin or whiskey has around 280 kilojoules. If you use a mixer that’s going to increase the kilojoules as well. So that can add up very quickly, especially if you’re on a night out. Your sleep quality is also going to be a lot poorer after alcohol, so that’s going to affect recovery, energy levels the next day, which can have a negative flow-on effect health wise. Abstaining from alcohol for a month or two can be a big drop in kilojoules which can help to lose weight.
Alcohol is a part of society, but it’s important to understand how it affects our recovery from exercise and contributes to our kilojoule intake so we can educate our clients about it, so they will be better off to make educated decisions and understand how it’s going to affect the outcomes of their health and fitness program.
References:
https://link.springer.com/article/10.1007/s00421-009-1311-3
https://journals.plos.org/plosone/articleid=10.1371/journal.pone.0088384&ref=popsugar.com&=___psv__p_5303184__t_w__r_www.popsugar.com%2Ffitness%2FOK-Drink-After-Working-Out-37812546_
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6309276/#:~:text=Alcohol%20intake%20was%20not%20associated,%25%20for%20consistent%2Dheavy%20drinkers.
https://www.researchgate.net/publication/353036224_Effect_of_previous-day_alcohol_ingestion_on_muscle_function_and_performance_of_severe-intensity_exercise
