It’s normal to have a few beers every now and then, especially after a tough sparing session, right? The purpose of this article is to identify whether this sort of drinking is interfering with your training gains. In this article, we’ll explore what alcohol is, and what it does to your body. You’ll also learn how to identify the quantity of alcohol in different types of drinks, so you can figure out how much you’re consuming. We’ll touch on what can happen to your body if you drink too much alcohol too often, and we’ll finish by exploring how alcohol consumption can influence your adaptation to training. So, let’s get into it.
What is alcohol, and what does it do to your body?
Alcohol, otherwise known as ethanol, or ethyl alcohol (chemical formula: C2H6O) is relatively small molecule. After ingestion, it travels through the stomach and on to the small intestine, where it is absorbed into the blood. This alcohol rich blood makes it way to the liver, where the bulk of alcohol metabolism takes place, but it can also be broken down in other places like the pancreas and brain, in addition to the gastrointestinal track.
The first step in breaking alcohol down involves enzymes (alcohol dehydrogenase [ADH], cytochrome P450 and catalase), which convert it into acetaldehyde. Acetaldehyde is then metabolized by another enzyme (aldehyde dehydrogenase), and we are left with acetate. Acetate is then broken down into water and carbon dioxide, which is easily eliminated from the body through urine, sweat, and even our expired breath.
The rate in which we absorb, move around, metabolize, and excrete alcohol ultimately determines our blood alcohol content. The average 70 kg male has the capacity to metabolically remove about 170 to 240 grams (g) of alcohol per day, or about 7 g per hour. Interesting, those that metabolize alcohol faster may be more immune to hangovers, but more research is required to figure this out.
Alcohol influences many neurotransmitter systems in the body (to name a few: gamma-aminobutyric acid [GABA], glutamate, serotonin, dopamine, and acetylcholine). Neurotransmitters are chemical messengers that relay signals between neurons, and other body tissues, like muscles or glands. Depending upon the specific brain region and neurotransmitter involved, alcohol can cause suppression or enhancement in motor control, motivation, working memory, and attention (Bjork & Gilman, 2014). Of course, the extent of impairment is related to many factors, including how much you drink.
How to measure a drink
Alcohol is measured in units. This allows one to compare the amount of pure alcohol in different drinks, like beer, wine, or spirits. But confusingly, different countries assign different quantities to one unit. In the UK for example, one unit is equal to 8 g of pure alcohol, but a standard drink in America contains 14 g of pure alcohol. This number falls to 13. 6 g in Canada, and 10 grams in Australia.
The number of grams of pure alcohol in any drink can be calculated by multiplying the volume of the drink in millilitres (1 fluid ounce = 29.5 mL) by the alcohol content by volume (remember, 5 % = 0.05, 12.5 % = 0.125, 40 % = 0.40). Once you have this number, then multiply it by the density of ethanol in one gram of alcohol (0.789 g/cm3), and this gives you the pure alcohol content in grams. See the example below for specific calculations.
Here are some example:
Beer example: 1 beer bottle contains 355 mL (12 fl oz.). Let’s say that beer is 5.0 % (or 0.05) alcohol by volume. 355 x 0.05 = 17.75 g of alcohol. Next, multiply this number by the density of alcohol to arrive at the total amount of pure alcohol. 17.75 x 0.789 = 14.0 g pure alcohol per bottle of beer.
Wine example: 1 serving of wine is just under 150 mL (5 fl oz). Let’s say that wine is 12.5 % (or 0.125) alcohol by volume. 150 x 0.125 = 18.75 g of alcohol. Next, multiply this number by the density of alcohol to arrive at the total amount of pure alcohol. 18.75 x 0.789 = 14.8 g pure alcohol per glass of wine.
Spirit example (Vodka): 1 serving of vodka is about 45 mL (1.5 fl oz). Let’s say that your vodka is 40 % (or 0.40) alcohol by volume. 45 x 0.4 = 18.0 g of alcohol. Next, multiply this number by the density of alcohol to arrive at the total amount of pure alcohol. 18.0 x 0.789 = 14.2 g pure alcohol per shot of vodka.
The World Health Organization (WHO, 2014) reports that 50.1 % of the global alcohol consumed is in the form of spirits, followed by beer (34.8 %). Beer is the most consumed type of beverage in Canada (51 %), America (50 %), and the United Kingdom (37 %).
Globally, the World Health Organization estimates that about 16 % of drinkers over 15 years of age engage in heavy episodic drinking. This is defined as 60 or more grams of pure alcohol (6 + standard drinks in most countries) on at least one single occasion at least monthly. In the United States, more than half of the adult population consume alcohol and about 5 % can be classified as heavy drinkers, which equates to more than seven standard drinks per week for women, and 14 for men (Esser et al., 2014).
Recommendations for alcohol are often expressed as units per day, or per week. But because the standard units differ by country, it’s probably easier to talk about grams of pure alcohol per day or week.
The United states recommends up to one drink per day for women, and twice that for men. For women, high risk drinking is considered 56 g or more of pure alcohol per day (about a bottle of wine), or 112 g/wk (about two bottles of wine). For men, high risk drinking is considered 70 g or more of pure alcohol per day (about 5 bottles of beer), or 210 g/wk (about 15 bottles of beer). If you’re at or above these numbers, your considered a heavy drinker. Finally, binge drinking is anything over 56 g in two hrs for women (a bottle of wine), or 70 g for men (5 bottles of beer) in the same time.
Example of recommendations in other countries
That’s 20 g/day (140 g/wk) in Australia, 27.2 g/d (190g/wk) in Canada, 16 g/d (112 g/wk) in the UK, and 14 to 28 g/d (0.5 to 1 fl oz/d) (196 g or 6.5 fl oz/wk) in the United States. Check out the drinking guidelines outlined by the International Alliance for Responsible Drinking here.
What happens to your body if you drink too much, or too often?
Alcohol related harm is related to the volume consumed, the pattern of drinking behavior (drinking whilst eating is not as bad as binge drinking through the night), and in rare occasions, the quality of alcohol consumed.
It may surprise you to learn that alcohol is an addictive psychoactive substance that is a component cause of +200 diseases/injuries, the most pressing of which include alcohol dependence, liver cirrhosis, cancers, and sudden injuries (WHO, 2014). In fact, heavy drinking has been linked with several diseases, many of which are outlined below.
- Neuropsychiatric conditions including epilepsy, depression, anxiety
- Gastrointestinal diseases including liver cirrhosis, pancreatitis
- Alcohol has been identified as carcinogenic and related to cancers of the mouth, nasopharynx, pharynx, oropharynx, laryngeal, oesophageal, colon, rectum, liver, breast, pancreas
- Intentional injuries like suicide, and unintentional ones.
- Cardiovascular disease including ischaemic heart disease and ischaemic stroke, hypertension, atrial fibrillation and haemorrhagic stroke.
- Fetal alcohol syndrome and preterm birth complications.
- Diabetes mellitus
- Infectious disease including pneumonia and tuberculosis
Separate from the toxic effect that alcohol exerts on organs and tissues, it can also cause harm in other ways. For example, intoxication leading to impairment of physical coordination, consciousness, cognition, perception, and behavior must also be considered, in addition to dependence, whereby the drinker’s self-control over their own behavior is impaired.
How does alcohol influence exercise performance?
Let’s assume that you, like most of us, are not a heavy drinker. Maybe you just go out with your team for a few drinks after a hard training session. Below, we’ll explore the possible influence this sort of drinking have on your performance.
A few studies have looked at the influence of drinking alcohol on recovery from exercise. For example, Haugvad et al., (2014) studied the influence of alcohol consumption on recovery from lower body resistance training. In this study participants consumed either no alcohol, a low alcohol dose (0.6 to 0.7g/kg, or about 2 to 4 shots of vodka for a 70-kg male) or a high dose (1.2 to 1.4 g/kg, or about 4 to 7 shots of vodka) after resistance training. Muscle strength was assessed shortly after alcohol ingestion, and again 12 and 24 hours later. The researchers found that strength and power were not impaired after consuming low or high doses of alcohol, but cortisol was higher and the testosterone-cortisol (T:C) ratio was lower after the high-dose of alcohol. A lowered T:C ratio may be associated with overtraining and lowered physical performance.
These findings are in general agreement with a series of experiments done by Barnes et al., in that lower alcohol doses of about 0.5 g/kg appear to have no significant influence on recovery of strength following exercise-induced muscle damage (Barnes et al., 2011). However, in a series of experiments this same research group observed that higher doses (1 g/kg of alcohol) consumed after muscle damage can slow recovery of strength (Barnes et al., 2010a, 2010b), possibly owing to reduced neural drive (Barnes 2012).
More recently the same research group, but lead by McLeay this time (McLeay et al., 2016), examined the influence of drinking on recovery from exercise-induced muscle damage in females. The team found that 0.88 g/kg of alcohol (about 2 to 4 shots of vodka for a 60 kg female) consumed after exercise-induced muscle damage did not affect recovery. This raises questions of whether the researchers gave a high enough alcohol dose to delay recovery. There could also be an oestrogen-related protective effect, or enhanced clearance of alcohol that may aid females in recovery from exercise-induced muscle damage. In any case, more research is required to explore the influence of alcohol on recovery from exercise-induced muscle damage in females.
What happens to my performance if I drink alcohol before exercise?
Low to moderate doses of alcohol do not positively influence performance, and probably hurt endurance performance, although the influence of alcohol consumption on strength measures requires clarification. In a study by Popovic et al., (2016), participants consumed 1.5 g/kg of alcohol (whiskey) in water, then completed a maximal aerobic test to exhaustion. The researchers found no significant reduction in cycling performance or peak oxygen consumption.
Alcohol ingestion after exercise may have several other negative effects that may ultimately influence your adaptation to training. For example, alcohol consumption may decrease the quality and duration of sleep (Roehrs et al., 2001). It may also influence hydration and body composition. Specifically, alcohol consumption increases urinary output through the inhibition of vasopressin (antidiuretic hormone), and the more hydrated you are, the greater the effect (Hobson & Maughan, 2010). What’s more, consuming higher doses of alcohol (0.92 g/kg, or about 3 to 4 shots of vodka for a 70 kg male) after exercise may delay the time it takes you to rehydrate, which may impair recovery, but doses less than 0.49 g/kg (about 1 to 2 shots) can probably be consumed without any negative effect on rehydration (Sherreffs et al., 1997).
With regards to nutrition, if you’re replacing your post-workout meal with alcohol, then you’ll probably slowdown the replacement of muscle glycogen, which may negatively influence your recovery (Burke et al., 2003). Also, the excess calories can make it harder to control body composition. Alcohol, or ethanol contains about 7 kcal per gram, whereas fats and protein have about 4 kcal/g, whilst fat has about 9 kcal per gram. But unlike fats, protein and carbohydrates, alcohol cannot be stored. Rather its metabolites remain dissolved in body water until elimination.
Alcohol consumption post-exercise may also impair immune function. Specifically, it may negatively influence the repair of skeletal muscle following injury (common in MMA sparring) by increasing blood flow at the site of injury, and may even increase your susceptibility to illness and infection (Messingham et al., 2002; Szabo & Mandrekar, 2009; Pedersen & Hoffman-Goetz, 2000).
Alcohol consumption may also negatively influence protein synthesis. Some researchers have suggested that consumption of alcohol can eliminate contraction-induced increase in skeletal muscle protein synthesis (Steiner & Lang 2015). Similarly, Parr et al., (2014) observed reduced rates of myofibrillar protein synthesis following strenuous exercise, even when co-ingested with whey protein and carbohydrates, suggesting suppression of anabolic response and recovery. It seems that high levels of repeated alcohol consumption after exercise may interfere with the benefits of resistance exercise by decreasing muscle protein synthesis and repair.
Taken together, these findings suggest that post-exercise alcohol consumption in high doses (>1 g/kg, may have a negative influence on your adaptation to training).
Conclusions: Can I optimize my adaptation to training, and still drink?
The effects of alcohol can be beneficial or harmful, depending on how much and how often you drink. There is little research in humans, but so far it appears that low to moderate doses (about 0.5 g/kg, or about 2 to 4 shots of vodka for a 70-kg male) have little to no influence on protein synthesis and protein balance. But high doses (greater than 1 g/kg, or about 4 to 7 shots of vodka) and chronic alcohol abuse will probably slow tissue recovery, impair protein synthesis, and lower your long-term adaptation to training, and that means less gains from training. Remember, alcohol is a poison.
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