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Alcohol After Training and Muscle: What the Studies Measured

10 min read

You finish a heavy session on Friday evening, and someone suggests the pub. Two hours later you are three pints in and wondering whether the drinks will cut into the work you put in.

You will hear both extremes on this. The research gives a narrower answer. In the studies covered here, muscle protein synthesis, the main short-term marker of muscle building, was measured after training at only one dose of alcohol, a high one. This guide covers what that trial found, how its dose compares with a night at the pub, what alcohol did not change, and how to plan your training around a night out.

24%
Lower muscle protein synthesis than protein alone, when alcohol was taken with protein
Parr 2014, 8 active men, 1.5g alcohol per kg
37%
Lower than protein alone, when alcohol was taken with carbohydrate instead of protein
Parr 2014, 8 active men
15
UK units of 8g in the trial dose for an average participant, the paper's 12 standard drinks (about 10g each)
Our calculation from Parr 2014 and the NHS unit size
14
Units a week the NHS advises men and women not to regularly exceed
NHS, Calculating alcohol units
Sources: Parr et al. 2014, PLoS One. NHS, Calculating alcohol units. The 15 units figure is our calculation from the trial dose and the NHS unit size.

What the research measured

Researchers study the hours after training by measuring myofibrillar protein synthesis, the rate at which your body builds the proteins that make muscle fibres contract. It is a short-term marker of the muscle building response, not a measure of muscle growth itself.

The main trial comes from Evelyn Parr and colleagues, published in PLoS One in 2014. Eight physically active men, average age 21, completed a hard session of leg extensions followed by cycling on three separate occasions, each time with a different recovery drink plan. In one, they drank 25g of whey protein straight after training and again 4 hours later. In another, they drank the same protein plus alcohol. In the third, they drank alcohol with carbohydrate instead of protein. Muscle biopsies taken 2 and 8 hours after training measured the synthesis rate between those two points.

Muscle protein synthesis rose above resting levels in all three conditions. Alcohol made the rise smaller. Compared with protein alone, synthesis was 24% lower when alcohol was taken with protein, and 37% lower when alcohol was taken with carbohydrate instead of protein. The 37% figure reflects both the alcohol and the missing protein. The authors concluded that alcohol suppressed the muscle building response and might impair recovery and adaptation to training.

A 2017 study by Anthony Duplanty and colleagues in the Journal of Strength and Conditioning Research put 10 resistance-trained men and 9 resistance-trained women through 6 sets of squats, followed by alcohol or a placebo. In the men, two signalling proteins that start muscle building, mTOR and S6K1, were less active 3 hours after the workout when the men drank alcohol than when they drank a placebo. In the women, the researchers found no such effect. The study did not measure muscle protein synthesis, and the sample was small, so the sex difference is an open question.

Muscle protein synthesis after training Relative to protein alone (100), 8 active men, Parr 2014 Protein only 100 Protein and alcohol 76 Carbohydrate and alcohol 63
Source: Parr et al. 2014, PLoS One, 8 physically active men, alcohol dose 1.5g per kg of body mass. Values are shown as a share of the protein-only result, from the 24% and 37% reductions the trial reported. Synthesis rose above resting levels in all three conditions.

Why the dose matters

The Parr dose was high. The alcohol was set at 1.5g per kg of body mass, drunk over 3 hours starting 1 hour after training. The men averaged 79kg, so the average dose was roughly 119g of pure alcohol. The NHS says a UK unit is 8g, so by our calculation that is about 15 units in one sitting. The paper reports the dose as 12 standard drinks, plus or minus 2, which works out at about 10g each.

The NHS advises men and women not to drink more than 14 units a week on a regular basis, and to spread drinking over 3 or more days if you regularly drink that much. The trial dose was about a week of that limit in one sitting. A pint of lower-strength lager at 3.6 per cent is 2 units. A pint at 5.2 per cent is 3 units. A 175ml glass of wine at 12 per cent is 2.1 units.

So three pints at 5.2 per cent comes to 9 units. That is below the Parr dose, but inside the range the wider review below tested for strength and soreness. No study here measured muscle protein synthesis at that level, so the synthesis findings tell you about heavy drinking straight after training.

A 2019 systematic review, a study that pools earlier studies, by Nemanja Lakicevic in the Journal of Functional Morphology and Kinesiology included 12 studies of alcohol after resistance exercise. The alcohol doses ranged between 0.6g and 1.5g per kg of body mass. For a 70kg man, the review puts that range at around 42g to 105g of alcohol, or 4.2 to 10.5 standard drinks of 10g. By our calculation, that is roughly 5 to 13 UK units. Doses scale with body weight, so heavier people received more. Only one study in the review, Parr, measured muscle protein synthesis, and it used the top dose. The lower doses were tested for strength, soreness and hormones.

What alcohol did not change

The review reported that force, power, muscular endurance, soreness and perceived exertion, how hard the effort felt, were unchanged after alcohol during recovery. In plain terms, in most of the studies reviewed, people who drank after training produced about the same performance in the tests that followed.

The review singled out two studies by Barnes and colleagues as exceptions. At 1g per kg, about 10 units for an 80kg man by our calculation, they found larger losses in peak torque, the maximum force a muscle produces, after alcohol, with the biggest drops at 36 hours. The review also reported that cortisol, a stress hormone, rose while testosterone, plasma amino acids and muscle protein synthesis fell after drinking.

None of the studies here randomised trained people to drink or not drink for months and then measured the muscle they built. In our view, that gap is the main limitation. Heavy doses lowered the short-term response, and the long-term effect is inferred rather than measured.

Where the evidence is thin

The samples are small, with 8 participants in the main trial. Parr tested only men, and Duplanty had only 9 women, which is why the sex difference needs more study. The only study that measured muscle protein synthesis used the top dose, so the evidence tells you little about how moderate drinking affects muscle building.

The evidence supports a claim about heavy drinking in the hours after training. It does not support a claim about all drinking at all doses, and it does not measure muscle gained over a training year.

A practical plan

These steps are ours, built from the studies above and NHS guidance. None of them were tested as a plan. In our view, you do not need to give up drinking to train well: keep heavy nights away from the sessions that matter, and keep your weekly total within the NHS limit.

1
Drink after your easiest session
The drop in the Parr trial was measured in the hours straight after hard training. If Friday night is the social one, make Friday a rest day or a light day, and move your heaviest lower-body work to a day you are not drinking.
2
Eat the protein anyway
In the Parr trial, protein taken with alcohol gave a 24% drop, against 37% with carbohydrate instead. The protein did not cancel the effect. Parr gave 25g of whey straight after training and again 4 hours later. A meal with protein before you go out was not tested, but it follows the same idea.
3
Watch the weekly total
The NHS advises no more than 14 units a week on a regular basis. Two pints of 5.2 per cent lager is 6 units, so two nights out at that rate comes to 12 of your 14 units. Count units rather than drinks, because strength varies widely.
4
Protect your sleep
A 2015 review by Mahesh Thakkar and colleagues reports that in healthy people without alcohol dependence, alcohol shortens the time to fall asleep and deepens sleep in the first half of the night, but disrupts sleep in the second half. In our view, finishing earlier leaves more of the night for undisturbed sleep.

Common mistakes

The first mistake is treating one drink as a ruined week. None of the studies here tested one drink. The second is the opposite error, using the finding that performance held up as proof that heavy drinking has no cost. Performance and muscle protein synthesis are two separate measurements, and the same review reported both.

The third mistake, in our view, is drinking heavily straight after your hardest session of the week. That is the scenario the Parr trial modelled most closely.

Frequently asked questions

Will two pints after the gym reduce my muscle gain?
No study here measured muscle protein synthesis at that dose. Two pints of 5.2 per cent lager is 6 units, about 48g of alcohol by our calculation. The falls of 24% and 37% came from about 15 units, and no study here measured long-term muscle gain.
Does a protein shake cancel out the alcohol?
Not in the Parr trial. Protein taken with alcohol still showed a 24% lower synthesis rate than protein alone. That was better than alcohol with carbohydrate, at 37% lower.
Are women affected in the same way?
Duplanty and colleagues found two muscle building signals were lower after alcohol in the men but not in the women in their study. The sample was 10 men and 9 women, which is too small to settle the question.
Should I skip my session the day after drinking?
The systematic review reported force, power and muscular endurance were unchanged after drinking in most studies, with two studies showing larger torque losses at 36 hours. In our view, train, but judge it on the day.
How many units is a standard drink in these studies?
The review defines a standard drink as 10g of alcohol, while the NHS says a UK unit is 8g. By our calculation, the Parr dose comes to about 15 UK units for an average participant. Checking the label beats estimating, because strength varies widely.

Bottom line

In the Parr trial, about 15 UK units after hard training lowered muscle protein synthesis by 24% with protein over the hours that were measured, though synthesis still rose above resting levels. A second study found lower muscle building signals in men. Across the review, short-term performance stayed mostly unchanged. None of the studies measured muscle protein synthesis after a pint or two, or measured muscle gained over months. Our advice: keep big nights away from your most important sessions and keep your weekly total within the NHS limit of 14 units.

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