Alcohol and Training
This one will either hit home or strike a chord… Either way, the purpose of this piece is to highlight the science behind the impact of alcohol consumption on our physiology as it pertains to training and recovery.
Many sociocultural and socioeconomic factors influence drinking culture. Who are the people that surround you, where is it that you spend most of your time, and what kind of work do you do? It’s easy to assume someone that who works in a health-centric environment, trains all the time, and eats nutritious food may not find themselves developing a habit of consuming alcohol. Although, it’s not always the case.
Alcohol consumption is quite prevalent within gym culture and among individuals who consider themselves avid fitness enthusiasts. Of course, enjoying a few drinks in moderation can be appropriate for some—depending on alcohol tolerance, baseline health, and history of relationship to substances—one of the best ways to support your decision-making when it comes to alcohol consumption is to educate yourself on its effects. The more knowledge you have, the more you can properly evaluate the risks associated with its consumption based on your current goals and health status.
“How much is too much?”
Before diving into the nitty gritty details of alcohol and its effects on the body, it's important to establish what is considered light to heavy consumption. These measures can often be subjective based on the peers surrounding you and the environment you generally spend your time in.
A study 1995 study by Dawson and colleagues stated the following:
Abstainer: drinks less than 0.01 fl oz alcohol per day (i.e., fewer than 12 drinks in the past year)
Light drinker: drinks 0.01 to 0.21 fl oz alcohol per day (i.e., 1 to 13 drinks per month)
Moderate drinker: drinks 0.22 to 1.00 fl oz alcohol per day (i.e., 4 to 14 drinks per week)
Heavier drinker: drinks more than 1.00 fl oz alcohol per day (i.e., more than 2 drinks per day)
While consumption statistics have changed drastically over the past few decades—especially following the pandemic—, the classification listed above remains appropriate as a reference today.
It all starts with the liver.
The liver is the largest organ in the body. It is the metabolic crossroads of the body. Your liver also plays a huge role in providing your body with the proper energy it needs to perform. It is responsible for breaking down, balancing, and creating the nutrients from the blood that filters through it from your stomach and small intestine. Anything ingested in the body from glucose, amino acids, and lipids will be metabolized by the liver to convert into usable compounds for energy. The liver is also responsible for the detoxification of the body. Removing any harmful substances from the bloodstream and turning them into waste for excretion.
During exercise, you will experience a build-up of lactate in the body and ammonia within the bloodstream to some degree. The higher the intensity of your training, the more build-up you will experience. If the body is unable to remove these bi-products in a timely and efficient manner, the output of your physical effort will diminish drastically and fatigue will kick in quickly. As the front runner of detoxification, the liver plays a direct role in the removal of these bi-products. If your liver isn’t able to function at its best, your body won’t be able to recover during your training and between sessions.
“What does alcohol have to do with my liver and my training?”
This organ has a tremendous ability to regenerate itself which explains our ability to consume a few drinks here and there without damaging our liver permanently. Of course, heavy alcohol consumption over several years can lead to long-lasting liver damage or cirrhosis.
After one drink, your liver begins the process of metabolizing alcohol. It sends out an enzyme called alcohol dehydrogenase (ADH) which converts alcohol to acetaldehyde through the chemical process of oxidation. Acetaldehyde is highly toxic to the body, even in low concentrations. This explains why as the liver becomes progressively more damaged over time, it becomes increasingly challenging for the body to rid itself of this compound.
The length of time it will take your liver to completely metabolize alcohol will depend on your age, body weight, height, body composition, and sex. Generally speaking, the liver can process one ounce of alcohol within one hour. If an individual consumes more, the surplus of alcohol will accumulate in the bloodstream and other tissues until it can be metabolized.
Now that you understand the role of the liver in alcohol breakdown, let’s get into some specifics about how alcohol affects other factors related to your physical and mental performance.
Alcohol and your sleep.
Alcohol is a depressant, which means it can make you feel drowsy and help you fall asleep faster initially. It impacts GABA (gamma-aminobutyric acid) neurotransmitter receptors in your brain which promote relaxation and sleepiness. In the context of sleep specifically, GABA plays a huge role in the initiation of sleep and maintenance of sleep architecture, such as cycling through deep sleep and REM phases.
Sure, alcohol may help you fall asleep faster, but just because you pass out quickly it doesn’t mean you’re getting adequate sleep quality. Alcohol disrupts the natural sleep cycle, leading to poorer quality sleep overall. It interferes with the REM (rapid eye movement) stage of sleep, which is crucial for cognitive function, memory consolidation, and emotional regulation.
In terms of the quantity of sleep you get, the duration of your shut-eye time at night might be the same however you may experience more fragmented sleep overall (ie. you’ll be waking up more throughout the night). This can lead to feeling less rested and refreshed in the morning.
On the long-term side of things, chronic consumption of alcohol around your sleep schedule can worsen preexisting sleep disorders or promote their development. This includes insomnia, nightmares, and sleep apnea.
Sleep, in general, is arguably the most important factor in determining your success rate in training and performance (that includes mental performance in your day-to-day). If your brain isn’t recovering, you best believe your body isn’t getting the recovery it needs either. If you value the work you put into your training, consider how alcohol consumption could be affecting the quality of sleep you’re getting.
Alcohol and Muscle Protein Synthesis.
Muscle protein synthesis (MPS) is the process by which cells in muscle tissue build new proteins, specifically those that makeup muscle fibers. This process is essential for muscle growth, repair, and maintenance. MPS occurs in response to various stimuli, with exercise and dietary protein intake being two primary factors that regulate its activity.
Given MSP is a crucial component of improving one’s strength and fitness, you can’t deny that alcohol consumption of any level could be impacting your training results.
In order for MSP to occur, your body needs to translate dietary protein into amino acids using a key regulator of MPS called the mTOR (mammalian target of rapamycin) signaling pathway. Consuming any level of alcohol will interfere with your body’s ability not only to put these amino acids to use in MSP and other metabolic processes but also to create amino acids in the first place. The dietary protein you’ll be consuming will be breaking down before your body can even start to make use of it. Therefore, you won’t be getting the necessary building blocks for muscular repair and growth post-training.
On the hormone side of things, alcohol suppresses testosterone and increases the secretion of cortisol which creates an unfavorable environment for muscle protein accretion. Testosterone activates signaling pathways for MSP to occur so if your baseline diminishes due to alcohol levels, your body won’t be able to facilitate proper muscle repair and growth. Testosterone also plays a big role in the metabolism of protein. Knowing that alcohol accelerates protein breakdown and interferes with protein synthesis as a whole, it makes sense that these processes would be heavily impacted by lower testosterone due to alcohol being present in the bloodstream.
Alcohol and Cortisol Levels.
Touching on cortisol for a hot second here as it’s not necessarily the devil in all cases. In this specific scenario, it’s definitely not doing you any favours.
Intentionally raising your cortisol levels through training and eating are controlled ways to help your body regulate this naturally occurring hormone. However, spiking your cortisol with the consumption of alcohol will only negatively impact your overall ability to recover and regulate your nervous system. Cortisol gets released as part of a stress response. Since alcohol triggers inflammation and oxidative stress in the body, it’s only normal for your system to respond by releasing more cortisol to fight it off.
On the sleep side of things, melatonin is essential for a restful night of quality sleep. The relationship between melatonin and cortisol acts more as a seesaw—if one goes up, the other comes down. Or, in this case, it can’t go up. Consuming alcohol naturally raises cortisol levels so although you might feel you can easily fall asleep as mentioned earlier, your body isn’t producing the appropriate amount of melatonin to regulate sleep architecture and sleep quality.
“Should I drink at all if I have serious training goals?”
Managing your consumption comes down to two major things:
What does your baseline health look like? What do your general health markers reflect? (ie. cortisol, blood glucose, insulin sensitivity, cholesterol, liver enzymes)
What are your training goals? (ie. looking to improve fitness vs looking to quality for the next Olympics as a triathlete)
These two points above will be the main determining factors as to what your consumption should look like to support your lifestyle choices and overall health. It’s very much a personal choice whether or not to abstain from alcohol entirely or to allow yourself the occasional drink. Making an informed decision based on the science is a great place to start.
Citations:
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.
Haugvad A, Haugvad L, Hamarsland H, Paulsen G. Ethanol does not delay muscle recovery but decreases testosterone/cortisol ratio. Med Sci Sports Exerc. 2014 Nov;46(11):2175-83. doi: 10.1249/MSS.0000000000000339. PMID: 24658221.
Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. Alcohol and sleep I: effects on normal sleep. Alcohol Clin Exp Res. 2013 Apr;37(4):539-49. doi: 10.1111/acer.12006. Epub 2013 Jan 24. PMID: 23347102.
Maher JJ. Exploring alcohol's effects on liver function. Alcohol Health Res World. 1997;21(1):5-12. PMID: 15706758; PMCID: PMC6826796.
Trefts E, Williams AS, Wasserman DH. Exercise and the Regulation of Hepatic Metabolism. Prog Mol Biol Transl Sci. 2015;135:203-25. doi: 10.1016/bs.pmbts.2015.07.010. Epub 2015 Aug 5. PMID: 26477916; PMCID: PMC4826571.
Dawson DA, Li TK, Grant BF. A prospective study of risk drinking: at risk for what? Drug Alcohol Depend. 2008 May 1;95(1-2):62-72. doi: 10.1016/j.drugalcdep.2007.12.007. Epub 2008 Feb 19. PMID: 18243584; PMCID: PMC2366117.