Alcohol is often seen as the perfect post-race or post-ride treat. Whether it’s a cold beer after a hot summer ride or a glass of champagne after a big victory, alcohol and athletics are inextricably linked. But what effect does alcohol have on human physiology and performance?
There are numerous tales of high-profile athletes abstaining from alcohol as they prepare for a big goal—Bradley Wiggins’ publicized abstinence during his run at the Tour de France is among the most famous. Inherently, it seems, we understand that too much alcohol will negatively impact many factors like weight, recovery, sleep, and, consequently, performance.
Indeed, the detrimental effects of alcohol, generally, on human physiology are well documented; in the short term it affects many aspects of metabolism, brain function, cardiovascular health, thermoregulation, and even skeletal muscle. (1)
What about when we imbibe less frequently or in small amounts? Are there subtle impacts to things like HRV, resting heart rate, and sleep quality that add up to significant detriments?
First, it’s worth noting that there are numerous factors that need to be taken into consideration when assessing how alcohol will impact an individual—everything from genetics to gender, from the amount of alcohol to the size and weight of the individual, among other factors. (2,3)
In terms of athletic performance, alcohol during an event has a host of impacts: It influences motor skills, disrupts hydration, and affects aerobic performance. Let’s hope you are not imbibing very often during events.
What’s more critical for athletes is how alcohol disrupts various aspects of the recovery process—which can, of course, have subsequent impacts on training and competition. (4,5)
Let’s take a closer look at how alcohol impacts various factors and functions that are involved in the recovery process.
Alcohol and muscle recovery
The effects of alcohol on recovery and sports performance is complicated. Many factors, including the timing of alcohol consumption after exercise and the recovery time required before your next training session or competition, not to mention the volume of alcohol consumed, all have an impact.
In general, the research suggests that alcohol may negatively impact immunoendocrine function, blood flow, and muscle protein synthesis (MPS). A 2014 study demonstrated that moderate alcohol consumption reduces the rate of muscle protein synthesis (MPS) following strenuous exercise even when co-ingested with protein. (6) The impact was significant—a 37% reduction of MPS.
The researchers, which included Dr. Louise Burke and Dr. John Hawley, two of the most prominent exercise physiologists, suggest that alcohol suppresses the MPS response in skeletal muscle and may, therefore, impair recovery and adaptation to training and even subsequent performances. And it appears the more you drink, the more alcohol disrupts MPS.
Other studies suggest recovery from skeletal muscle injury would be impaired for similar reasons. (7)
Other factors related to recovery, such as rehydration and glycogen resynthesis, are affected to a lesser extent.
A 2019 review study found that alcohol consumption following resistance exercise doesn’t seem to affect the majority of biological and physical measures. However, levels of cortisol were increased, and levels of testosterone and rates of muscle protein synthesis were decreased, which indicates that long-term muscular adaptations could be impaired if alcohol consumption during recovery is consistent. Likewise, muscle function doesn’t seem to be influenced by alcohol consumption during recovery. (8)
Alcohol and sleep
The impact of alcohol on sleep has been widely studied. Initially, alcohol acts as a sedative—the length of time it takes to fall asleep in subjects is reduced. However, many studies suggest that REM sleep is suppressed, with a longer delay to REM sleep and decreased REM sleep in the first half of the night or, depending on how much alcohol is consumed, the entire night. (9)
Numerous studies demonstrate that after consuming alcohol, sleep in the second half of the night is disrupted, with increased wakefulness and/or stage 1 sleep. This pattern of initially feeling drowsy followed by a period of poor quality sleep can lead to a downward spiral. As the night progresses, it can create an imbalance between slow-wave sleep and REM sleep. The result is less restorative sleep and more slow-wave sleep. Thus, overall sleep quality decreases, which usually results in shorter sleep duration and more sleep disruptions. (10)
How much alcohol do you have to consume for it to negatively impact sleep? A 2018 study asked this question, comparing sleep quality (derived from HRV data) among subjects who consumed varying amounts of alcohol. They found that low amounts of alcohol (defined as fewer than two servings per day for men or one serving per day for women) decreased sleep quality by 9.3%. Moderate amounts of alcohol (two servings per day for men or one serving per day for women) decreased sleep quality by 24%. And high amounts of alcohol (more than two servings per day for men or one serving per day for women) decreased sleep quality by 39.2%. (11)
Wearable technology, in particular Whoop, has gathered large quantities of data that give a glimpse of how alcohol impacts HRV and sleep. Though the research is not peer-reviewed, it does add an extra layer of evidence that alcohol negatively disrupts sleep, HRV, resting heart rate (RHR), and your readiness to train and perform. See the story from Whoop: Pour Decisions: How Alcohol Negatively Affects Your Biometric Data.
To learn more about the importance of sleep and how it is particularly critical in the recovery process, listen to Fast Talk Episode 135: The Importance of Sleep, Monitoring Devices, and Changing Your Routine, with Dr. Shona Halson.
Alcohol and the immune system
Many athletes are notorious for being hypochondriacs, especially in the race season. Getting sick disrupts training, recovery, and competition, which is why it is important to understand how and to what extent alcohol can have a negative impact on immune system function.
The gastrointestinal (GI) system is the first point of contact for alcohol as it passes through the body. One of the most significant immediate effects of alcohol is that it affects the structure and integrity of the GI tract. (12)
Alcohol has been shown to alter the number of microbes in the gut microbiome. This abundance of microorganisms in the intestine aids in normal gut function and affects the maturation and function of the immune system.
Alcohol disrupts communication between these organisms and the intestinal immune system. Not only that, alcohol also damages epithelial cells, T cells, and neutrophils in the GI system, disrupting gut barrier function and facilitating leakage of microbes into the bloodstream. (12)
So, should you abstain?
There are many factors that influence how alcohol impacts an individual, including weight, gender, and genetics. Likewise, the volume and timing of alcohol consumption can drastically alter the effects it will have on sleep, immune function, and other biomarkers like HRV and RHR.
If you’re trying to peak in January for a big event, it would be best to abstain altogether to eke out every bit of performance from yourself. If it’s the off-season, but you don’t want to fall too far from where you’re at, drink in moderation (less than two drinks for men and one drink for women) and try to stop drinking four to five hours before going to bed.
References
- Vella LD, Cameron-Smith D. Alcohol, athletic performance and recovery. Nutrients. 2010 Aug;2(8):781-9. doi: 10.3390/nu2080781. Epub 2010 Jul 27.
- Alcohol metabolism: An update. Alcohol alert. National Institute on Alcohol Abuse and Alcoholism. 2007. Retrieved 2016 from http://pubs.niaaa.nih.gov/publications/AA72/AA72.htm
- Boyle, M, and Long, S. Personal Nutrition. Belmont, CA: Thomson/Wadsworth; 251-263, 2007.
- Barnes, M. Alcohol: Impact on sports performance and recovery in male athletes. Sports Med 44(7): 909-919, 2014.
- Koziris, L. Alcohol and athletic performance. American College of Sports Medicine Current Comment. April, 2000.
- Parr EB, Camera DM, Areta JL, Burke LM, Phillips SM, Hawley JA, Coffey VG. Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training. PLoS One. 2014 Feb 12;9(2):e88384. doi: 10.1371/journal.pone.0088384. PMID: 24533082; PMCID: PMC3922864.
- Barnes MJ. Alcohol: impact on sports performance and recovery in male athletes. Sports Med. 2014 Jul;44(7):909-19. doi: 10.1007/s40279-014-0192-8. PMID: 24748461.
- Lakićević N. The Effects of Alcohol Consumption on Recovery Following Resistance Exercise: A Systematic Review. J Funct Morphol Kinesiol. 2019 Jun 26;4(3):41. doi: 10.3390/jfmk4030041. PMID: 33467356; PMCID: PMC7739274.
- Colrain IM, Nicholas CL, Baker FC. Alcohol and the sleeping brain. Handb Clin Neurol. 2014;125:415-31. doi: 10.1016/B978-0-444-62619-6.00024-0. PMID: 25307588; PMCID: PMC5821259.
- Sleep Foundation. https://www.sleepfoundation.org/nutrition/alcohol-and-sleep
- Pietilä J, Helander E, Korhonen I, Myllymäki T, Kujala UM, Lindholm H. Acute Effect of Alcohol Intake on Cardiovascular Autonomic Regulation During the First Hours of Sleep in a Large Real-World Sample of Finnish Employees: Observational Study. JMIR Ment Health. 2018 Mar 16;5(1):e23. doi: 10.2196/mental.9519. PMID: 29549064; PMCID: PMC5878366.
- Sarkar D, Jung MK, Wang HJ. Alcohol and the Immune System. Alcohol Res. 2015;37(2):153–5. PMCID: PMC4590612.
